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blues90
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Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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 Posted: Mon Aug 19, 2019 1:23 pm Post subject: FI HTS ? |
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There is a chart I think Donnie Strickland posted from Richard Atwell's site that shows the temps and ohm readings . Here is what I find. per the chart @68*F the resistance should be a new sensor 2300 ohm old sensor 2300 ohm.
The one in my car which is pretty old at least 20 years reads 2250 ohm @ 90*F using a thermometer engine cold I've seen it as high as 2272ohm. I have another just as old that I tested on hot water and @72 *F read 3000 ohm .
This tells me it's way rich on start up and all I know is the one in the car in 2 minutes went from 2272 ohm to 77.2 ohm after I stared the engine. Both are Bosch 0 280 030 003.
All I know it they should have a curve and the one I did test did yet it still starts out to high = rich.
I have replaced all the gaskets and runner boots and vacuum lines sealed the IAD rear cover and took apart the electric AAR and cleaned and lubed it so it now closes yet when I start it I still feel it's a bit rough for about the 2 minutes and I still have t have the air intake temp sensor unplugged or it will not have a steady idle also if I start it with the air temp sensor connected it runs fine until the 2 minutes pass then the idle drops 200 RPM and it has the erratic miss not one cylinder it's random meaning I can't isolate it to one cylinder which is why I call it random. It gets worse if I raise the RPM unless I unplug the air temp sensor.
I bought a new HTS not the one bus depot sells one that most other online VW parts sellers offer Uro parts 311906041A.
I'm thinking about just installing it and see if anything changes , I haven't tested it yet it does read lower @90*F by about 400 ohm which brings it pretty close to the graph .
This is the one issue that's been driving me nuts since 2009. I know what is working this seems to be the only thing I can find that is working yet out of spec from what I can find. Fact is changing all the vacuum lines and injector seals and runner boots didn't change a thing , not that they didn't need to be done from age alone.
Any thought's? |
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raygreenwood
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Joined: November 24, 2008
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Location: Oklahoma City
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| Posted: Mon Aug 19, 2019 9:16 pm Post subject: Re: FI HTS ? |
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The difference in 400-500 ohms is not heavily rich.
And...if you have to unplug the temp sensor 1 in some climates/seasons to idle well....this is indicating the need to make a tweak to the baseline fuel mixture at the MPS. Ray |
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Tram
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Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Mon Aug 19, 2019 9:36 pm Post subject: Re: FI HTS ? |
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Ratwell's site is for Bay Bus, which is L-Jet (or AFC) fuel injection anyways. Let me look in the K manual for D-Jet tomorrow.
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blues90
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Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Tue Aug 20, 2019 10:28 am Post subject: Re: FI HTS ? |
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| raygreenwood wrote: |
The difference in 400-500 ohms is not heavily rich.
And...if you have to unplug the temp sensor 1 in some climates/seasons to idle well....this is indicating the need to make a tweak to the baseline fuel mixture at the MPS. Ray |
All I'm going by is even as vague as the Bentley is the one spec they do offer in the test using the Bosch tester is the "reading about 2500 ohm" they mention 68*F same for the TS-1. When I read close to 2500 ohm @90*F makes me wonder. Plus I don't have a clue what the head temp is other than at start up.
As far as TS-1 it only reaches the lowest temp here when I drive of about 60*F and can reach 100*F and it acts the same way with TS-1 plugged in. TS-1 is close to 300 ohm cold and around 50 ohm hot. I've checked and it's not shorted internally each pin to the body of the sensor itself.
Before all this I never had this issue until 2009 and then I was using an MPS that wasn't the proper part number which I didn't even know till 5 years ago . it looked identical to the original and the proper one in the car now . Back then I didn't have a PC just books I had a spare that looked new so I used it worked fine . It's an E system. Even with the original way back in 95 trying to pass smog here it was running just a bit high at idle so I popped the black cap marked the slotted screw position and turning it either way just a hair made it run worse, it ran and idled great right where it was.
To be honest, I could care less if the TS-1 just plugs a hole and goes along for the ride with the plug hanging. What I do care about is running too rich or lean. The spark plugs I replaced with NGK were Bosch proper number less than 1500 miles looked dry /black /sooty. Did this when I did all the rest of the work in May . Plus it doesn't help that my fuel gauge sender is now far from steady< I just know when it stays near the red to get gas and even with a full tank I don't get many miles going by the trip odometer before it reads steady near the red zone. I never see black smoke out the exhaust . When it's near the red I usually get $20 worth 4 gallons and it's right near the half tank mark yet the next day turn on the key it will read over this or under . It used to read above the full mark filled now it's a bit under. Point is I have no idea what the actual millage is. Plus any time I plug the TS-1 in the RPM drops 200 RPM consistent add it the random miss and unsteady RPM rise from 1000 RPM to 2300 RPM then it rises smooth or rather has a smooth transition rather than like it's fighting itself. All this clears the instant I unplug TS-1 . If I plug in TS-1 , bring the idle up the 200 RPM and drive the car it seems fine since it now has a load on it. I just fear it's to lean. I even left the ohm meter on TS-2 to watch the ohm drop and see if at any time it goes open or shorts. All I see is it seems to drop fairly quick. |
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blues90
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Joined: March 14, 2009
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Location: Hollywood ,CA
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| Posted: Tue Aug 20, 2019 10:33 am Post subject: Re: FI HTS ? |
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| Tram wrote: |
| Ratwell's site is for Bay Bus, which is L-Jet (or AFC) fuel injection anyways. Let me look in the K manual for D-Jet tomorrow. |
Thanks Tram. I used that chart because it's the only one I could find seemed like at least a good reference point. Similar TS-2 HTS. I can't find what TS-1 is supposed to be either. |
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KTPhil 
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Posts: 34021
Location: Conejo Valley, CA
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| Posted: Tue Aug 20, 2019 3:13 pm Post subject: Re: FI HTS ? |
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Part numbers and nomenclature:
TS#1: 311 906 081A (intake air sensor)
TS#2: 311 906 041A (cylinderhead sensor)
Bosch # 0 280 130 012
Values are from Russ Wolfe's lost site, based on VW workshop manual values.
Last edited by KTPhil on Tue Aug 20, 2019 5:15 pm; edited 1 time in total |
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blues90
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Location: Hollywood ,CA
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| Posted: Tue Aug 20, 2019 4:34 pm Post subject: Re: FI HTS ? |
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on that chart @75*F it would be 2000 ohm @ 90*F it should be well below that. I assume the bottom line is 0 ohm and between that and 2000 is 1000 ohm . I divide 50 * x 4 and get 12.5 * making 75*F the middle just to break it down a bit. The one in my heap reads 2250 ohm @ 90*F. I'd say @ close to 115*F I should see 1000 ohm or close to it. I haven't checked TS1 in a while yet recall it reading above 300 ohm @ 75*F so it's way high on that chart , I need to check it again. Yet if it did then it should not lean it out when it plug it in and as far as I know it could be making it richer, I have no way to tell without a sniffer. All I do know is if TS2 is to rich and it idles yet not great if I plug in TS1 it's better yet only for a few minutes before the RPM drops from 1000 to 800 and begins the erratic miss the second I unplug TS1 it idles fine . I repaired the electric AAR since it was sticking so now once I start it as before the idle is 850 than after a few minutes it goes up to 1200 then I drive it till hot and have an 850 RPM in drive and 1000 in park this is with TS1 unplugged. Plug in TS1 and the idle always drops 200 RPM at idle hot or cold . If I can believe the brown Bentley it states TS1 is calibrated @68 *F it does not say what it should read. @ 68*F. After a few minutes TS1 drops real fast to below 100 ohm.
Last edited by blues90 on Tue Aug 20, 2019 5:21 pm; edited 2 times in total |
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KTPhil
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Location: Conejo Valley, CA
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| Posted: Tue Aug 20, 2019 5:15 pm Post subject: Re: FI HTS ? |
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VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
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blues90
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Posts: 1912
Location: Hollywood ,CA
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| Posted: Tue Aug 20, 2019 5:35 pm Post subject: Re: FI HTS ? |
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| KTPhil wrote: |
VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
Yes I've read that. what about TS1 which Bentley also has ass backward calling TS2 TS1. I recall adding over 500 ohms to TS2 before while having TS1 connected then if I unplugged TS1 it ran the same without the 500 ohm resister on TS2 so I was right back to where I started. If TS1 should read what the chart you posted states then I need to reduce the resistance of TS1 so I can't add resistance in series it needs to be in parallel meaning across TS1 terminals.
I think the important thing is how fast the 2 temp sensors react. I think if they drop to fast then it leans out well before the AAR has a chance to close which in itself makes the mix richer. I know my TS2 drops from 2272 to 77.5 ohms in 2 minutes. By then it's out of the picture and who knows what TS1 does it also drops fast yet seems out of spec if there is such a thing. Sure you can still get one if you have over $100 to spend and hope it reads different than the one I have. I don't have that sort of money to spend. I'd be better off to just get a set of carbs. Of course I've already spent more than I should have on fuel injected parts so it's a bit to late now. |
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raygreenwood
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Joined: November 24, 2008
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Location: Oklahoma City
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| Posted: Tue Aug 20, 2019 8:18 pm Post subject: Re: FI HTS ? |
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| blues90 wrote: |
| KTPhil wrote: |
VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
Yes I've read that. what about TS1 which Bentley also has ass backward calling TS2 TS1. I recall adding over 500 ohms to TS2 before while having TS1 connected then if I unplugged TS1 it ran the same without the 500 ohm resister on TS2 so I was right back to where I started. If TS1 should read what the chart you posted states then I need to reduce the resistance of TS1 so I can't add resistance in series it needs to be in parallel meaning across TS1 terminals.
I think the important thing is how fast the 2 temp sensors react. I think if they drop to fast then it leans out well before the AAR has a chance to close which in itself makes the mix richer. I know my TS2 drops from 2272 to 77.5 ohms in 2 minutes. By then it's out of the picture and who knows what TS1 does it also drops fast yet seems out of spec if there is such a thing. Sure you can still get one if you have over $100 to spend and hope it reads different than the one I have. I don't have that sort of money to spend. I'd be better off to just get a set of carbs. Of course I've already spent more than I should have on fuel injected parts so it's a bit to late now. |
Bentley only has it wrong...depending on the year of the Bentley 
At some point/year...TS-1 and TS-2 swapped positions.
The CHT...lets call it that....the late one mounted in the cylinder head....is sensitive and fast. It starts dropping in about a minute after running in 60-70-ish degree weather. Even faster if its 90F outside.
The D-jet system does not care about 50 or even 100 degree jumps in the scale....depending on where in the scale we are.....because you have to remember that the CHT is not the only thing starting at one point dead cold and affecting the fuel mixture.
You start the car at 73F outside....and its a race....the CHT is dropping about 100 ohms every 30 seconds or so. The TS-1 drops a little as air moves past it and slowly drops a little more...and then later rises because it picks up conducted heat. Meanwhile....the AAR is closing.
All of these affect fuel mixture. maybe 5-10% for TS-1....maybe 10% for TS-2 (CHT)....and an easy 25% or more for the AAR...because extra air causes a HUGE reaction from the MPS. It thinks the throttle is open.
By the time you get down to about 300-400 ohms in the CHT....it slows a little. The heads warm up fast but not that fast unless you are standing on it.
A few minutes later...you get into the last 200 ohms. The problem with teh cHT is that is "should" stop there...but does not. It continues down below 200....where its hard for it to come up higher to have any effect as you cool off...stop for soda...idle in the shade etc. At 200 ohms its maximum lean.
So...saying 3-5 minutes after start up that its running slightly rough....its not even warmed up yet.
And all of these little tweaks...10% here and there.....affect the vacuum signature. That affects the MPS...that affects the running. Ray |
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blues90
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Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Tue Aug 20, 2019 10:59 pm Post subject: Re: FI HTS ? |
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| raygreenwood wrote: |
| blues90 wrote: |
| KTPhil wrote: |
VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
Yes I've read that. what about TS1 which Bentley also has ass backward calling TS2 TS1. I recall adding over 500 ohms to TS2 before while having TS1 connected then if I unplugged TS1 it ran the same without the 500 ohm resister on TS2 so I was right back to where I started. If TS1 should read what the chart you posted states then I need to reduce the resistance of TS1 so I can't add resistance in series it needs to be in parallel meaning across TS1 terminals.
I think the important thing is how fast the 2 temp sensors react. I think if they drop to fast then it leans out well before the AAR has a chance to close which in itself makes the mix richer. I know my TS2 drops from 2272 to 77.5 ohms in 2 minutes. By then it's out of the picture and who knows what TS1 does it also drops fast yet seems out of spec if there is such a thing. Sure you can still get one if you have over $100 to spend and hope it reads different than the one I have. I don't have that sort of money to spend. I'd be better off to just get a set of carbs. Of course I've already spent more than I should have on fuel injected parts so it's a bit to late now. |
Bentley only has it wrong...depending on the year of the Bentley
At some point/year...TS-1 and TS-2 swapped positions.
The CHT...lets call it that....the late one mounted in the cylinder head....is sensitive and fast. It starts dropping in about a minute after running in 60-70-ish degree weather. Even faster if its 90F outside.
The D-jet system does not care about 50 or even 100 degree jumps in the scale....depending on where in the scale we are.....because you have to remember that the CHT is not the only thing starting at one point dead cold and affecting the fuel mixture.
You start the car at 73F outside....and its a race....the CHT is dropping about 100 ohms every 30 seconds or so. The TS-1 drops a little as air moves past it and slowly drops a little more...and then later rises because it picks up conducted heat. Meanwhile....the AAR is closing.
All of these affect fuel mixture. maybe 5-10% for TS-1....maybe 10% for TS-2 (CHT)....and an easy 25% or more for the AAR...because extra air causes a HUGE reaction from the MPS. It thinks the throttle is open.
By the time you get down to about 300-400 ohms in the CHT....it slows a little. The heads warm up fast but not that fast unless you are standing on it.
A few minutes later...you get into the last 200 ohms. The problem with teh cHT is that is "should" stop there...but does not. It continues down below 200....where its hard for it to come up higher to have any effect as you cool off...stop for soda...idle in the shade etc. At 200 ohms its maximum lean.
So...saying 3-5 minutes after start up that its running slightly rough....its not even warmed up yet.
And all of these little tweaks...10% here and there.....affect the vacuum signature. That affects the MPS...that affects the running. Ray |
Mine is a late 73 . The CHT in there now at 90 *F starts out at 2270 and nose dives to 77.5 ohm in 2 minutes if it ever see's 200 ohm it has to be a nano second if at all . If I at least try the new one it might at least have a more steady and slower drop , might is the key here. THis might give the AAR a bit more time to close. I need to see what the intake temp does as far as at the same temp to see what it starts at and how far and fast it drops down in ohms as it heats up. I know you are getting at adjusting the MPS , I'm just not ready to screw with it just yet not until I know how the other sensors act, I just don't see the point . It all worked just fine until 2009 I replaced every thing else that could be a vacuum leak and got nowhere. The only thing that helped was repairing the AAR so it closes. I even went as far as adjusting the spring so it would close faster we PMed about this . How long can a HTS live with decades of heat cycles before it just is garbage the air temp does not see even close to the temps and may last for decades with no ill affect. |
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Bobnotch
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Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Wed Aug 21, 2019 6:13 am Post subject: Re: FI HTS ? |
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| blues90 wrote: |
| How long can a HTS live with decades of heat cycles before it just is garbage the air temp does not see even close to the temps and may last for decades with no ill affect. |
I don't know. Most of the old ones I've ran into had the wire break off first. I've changed a couple, mostly trying to find a better sensor, but then I didn't know ant better. I've also ballasted a couple trying to richen up the system without digging into the MPS.
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Wed Aug 21, 2019 10:37 am Post subject: Re: FI HTS ? |
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| blues90 wrote: |
| raygreenwood wrote: |
| blues90 wrote: |
| KTPhil wrote: |
VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
Yes I've read that. what about TS1 which Bentley also has ass backward calling TS2 TS1. I recall adding over 500 ohms to TS2 before while having TS1 connected then if I unplugged TS1 it ran the same without the 500 ohm resister on TS2 so I was right back to where I started. If TS1 should read what the chart you posted states then I need to reduce the resistance of TS1 so I can't add resistance in series it needs to be in parallel meaning across TS1 terminals.
I think the important thing is how fast the 2 temp sensors react. I think if they drop to fast then it leans out well before the AAR has a chance to close which in itself makes the mix richer. I know my TS2 drops from 2272 to 77.5 ohms in 2 minutes. By then it's out of the picture and who knows what TS1 does it also drops fast yet seems out of spec if there is such a thing. Sure you can still get one if you have over $100 to spend and hope it reads different than the one I have. I don't have that sort of money to spend. I'd be better off to just get a set of carbs. Of course I've already spent more than I should have on fuel injected parts so it's a bit to late now. |
Bentley only has it wrong...depending on the year of the Bentley
At some point/year...TS-1 and TS-2 swapped positions.
The CHT...lets call it that....the late one mounted in the cylinder head....is sensitive and fast. It starts dropping in about a minute after running in 60-70-ish degree weather. Even faster if its 90F outside.
The D-jet system does not care about 50 or even 100 degree jumps in the scale....depending on where in the scale we are.....because you have to remember that the CHT is not the only thing starting at one point dead cold and affecting the fuel mixture.
You start the car at 73F outside....and its a race....the CHT is dropping about 100 ohms every 30 seconds or so. The TS-1 drops a little as air moves past it and slowly drops a little more...and then later rises because it picks up conducted heat. Meanwhile....the AAR is closing.
All of these affect fuel mixture. maybe 5-10% for TS-1....maybe 10% for TS-2 (CHT)....and an easy 25% or more for the AAR...because extra air causes a HUGE reaction from the MPS. It thinks the throttle is open.
By the time you get down to about 300-400 ohms in the CHT....it slows a little. The heads warm up fast but not that fast unless you are standing on it.
A few minutes later...you get into the last 200 ohms. The problem with teh cHT is that is "should" stop there...but does not. It continues down below 200....where its hard for it to come up higher to have any effect as you cool off...stop for soda...idle in the shade etc. At 200 ohms its maximum lean.
So...saying 3-5 minutes after start up that its running slightly rough....its not even warmed up yet.
And all of these little tweaks...10% here and there.....affect the vacuum signature. That affects the MPS...that affects the running. Ray |
Mine is a late 73 . The CHT in there now at 90 *F starts out at 2270 and nose dives to 77.5 ohm in 2 minutes if it ever see's 200 ohm it has to be a nano second if at all . If I at least try the new one it might at least have a more steady and slower drop , might is the key here. THis might give the AAR a bit more time to close. I need to see what the intake temp does as far as at the same temp to see what it starts at and how far and fast it drops down in ohms as it heats up. I know you are getting at adjusting the MPS , I'm just not ready to screw with it just yet not until I know how the other sensors act, I just don't see the point . It all worked just fine until 2009 I replaced every thing else that could be a vacuum leak and got nowhere. The only thing that helped was repairing the AAR so it closes. I even went as far as adjusting the spring so it would close faster we PMed about this . How long can a HTS live with decades of heat cycles before it just is garbage the air temp does not see even close to the temps and may last for decades with no ill affect. |
What you are describing.....is 100% normal.
Its a thermistor. Some may be a "little" faster or slower but not much.
And...about 75 ohms...is exactly where they all will end up. Its too low....but thats the profile especially in hot weather. In the winter you may get lucky and have it stop in the 125-175-ish range....but the fact of the mater is....most D-jet (I think there were some variations from year to year and system to system)...stop leaning out in the 150-200 ohm range from reading some of Brad Anders tech.
And I keep saying this....quit freaking out about working with the MPS. If your engine has high miles...it does not have the factory vacuum signature.
If your engine has been rebuilt...it does not have the factory vacuum signature.
If your engine does not have factory average compression....it does not have the factory vacuum signature.
If your engine has larger valves, a different cam, differences in ignition, differences in fuel pressure, has a different exhaust/muffler....it does not have the factory vacuum signature.
If your engine has low voltage...or a worn throttle plate with air seeping around it (and whose does not with a type 3)....you do not have the factory vacuum signature.
If you have the oil heated AAR and its less than absolutely perfect in function...you do not have the factory vacuum signature.
The MPS was set up based around a NEW engine vacuum signature. Yes...it has some variance range to paper over that....but its a narrow range.
Add to that....any variances in TS-1 and/or TS-2 and/or harness resistance......and you do not have the factory vacuum signature.
If any of the above applies to your engine....unless you are going to fix all of that....just adjust the damn MPS to fit the new vacuum signature.
I agree in principle...make sure the TS-1 and TS-2 are nominal. But outside of making sure the range is correct and they consistently do the same thing....just adjust the MPS. Ray |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Wed Aug 21, 2019 11:04 am Post subject: Re: FI HTS ? |
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| raygreenwood wrote: |
| blues90 wrote: |
| raygreenwood wrote: |
| blues90 wrote: |
| KTPhil wrote: |
VW called out a 10% margin on these readings as normal.
They also had a fix of adding a 250 ohm resistor in series to the head sensor to solve certain hot mixture problems, so a reading above these when hot may pose no problem, and might even solve them! |
Yes I've read that. what about TS1 which Bentley also has ass backward calling TS2 TS1. I recall adding over 500 ohms to TS2 before while having TS1 connected then if I unplugged TS1 it ran the same without the 500 ohm resister on TS2 so I was right back to where I started. If TS1 should read what the chart you posted states then I need to reduce the resistance of TS1 so I can't add resistance in series it needs to be in parallel meaning across TS1 terminals.
I think the important thing is how fast the 2 temp sensors react. I think if they drop to fast then it leans out well before the AAR has a chance to close which in itself makes the mix richer. I know my TS2 drops from 2272 to 77.5 ohms in 2 minutes. By then it's out of the picture and who knows what TS1 does it also drops fast yet seems out of spec if there is such a thing. Sure you can still get one if you have over $100 to spend and hope it reads different than the one I have. I don't have that sort of money to spend. I'd be better off to just get a set of carbs. Of course I've already spent more than I should have on fuel injected parts so it's a bit to late now. |
Bentley only has it wrong...depending on the year of the Bentley
At some point/year...TS-1 and TS-2 swapped positions.
The CHT...lets call it that....the late one mounted in the cylinder head....is sensitive and fast. It starts dropping in about a minute after running in 60-70-ish degree weather. Even faster if its 90F outside.
The D-jet system does not care about 50 or even 100 degree jumps in the scale....depending on where in the scale we are.....because you have to remember that the CHT is not the only thing starting at one point dead cold and affecting the fuel mixture.
You start the car at 73F outside....and its a race....the CHT is dropping about 100 ohms every 30 seconds or so. The TS-1 drops a little as air moves past it and slowly drops a little more...and then later rises because it picks up conducted heat. Meanwhile....the AAR is closing.
All of these affect fuel mixture. maybe 5-10% for TS-1....maybe 10% for TS-2 (CHT)....and an easy 25% or more for the AAR...because extra air causes a HUGE reaction from the MPS. It thinks the throttle is open.
By the time you get down to about 300-400 ohms in the CHT....it slows a little. The heads warm up fast but not that fast unless you are standing on it.
A few minutes later...you get into the last 200 ohms. The problem with teh cHT is that is "should" stop there...but does not. It continues down below 200....where its hard for it to come up higher to have any effect as you cool off...stop for soda...idle in the shade etc. At 200 ohms its maximum lean.
So...saying 3-5 minutes after start up that its running slightly rough....its not even warmed up yet.
And all of these little tweaks...10% here and there.....affect the vacuum signature. That affects the MPS...that affects the running. Ray |
Mine is a late 73 . The CHT in there now at 90 *F starts out at 2270 and nose dives to 77.5 ohm in 2 minutes if it ever see's 200 ohm it has to be a nano second if at all . If I at least try the new one it might at least have a more steady and slower drop , might is the key here. THis might give the AAR a bit more time to close. I need to see what the intake temp does as far as at the same temp to see what it starts at and how far and fast it drops down in ohms as it heats up. I know you are getting at adjusting the MPS , I'm just not ready to screw with it just yet not until I know how the other sensors act, I just don't see the point . It all worked just fine until 2009 I replaced every thing else that could be a vacuum leak and got nowhere. The only thing that helped was repairing the AAR so it closes. I even went as far as adjusting the spring so it would close faster we PMed about this . How long can a HTS live with decades of heat cycles before it just is garbage the air temp does not see even close to the temps and may last for decades with no ill affect. |
What you are describing.....is 100% normal.
Its a thermistor. Some may be a "little" faster or slower but not much.
And...about 75 ohms...is exactly where they all will end up. Its too low....but thats the profile especially in hot weather. In the winter you may get lucky and have it stop in the 125-175-ish range....but the fact of the mater is....most D-jet (I think there were some variations from year to year and system to system)...stop leaning out in the 150-200 ohm range from reading some of Brad Anders tech.
And I keep saying this....quit freaking out about working with the MPS. If your engine has high miles...it does not have the factory vacuum signature.
If your engine has been rebuilt...it does not have the factory vacuum signature.
If your engine does not have factory average compression....it does not have the factory vacuum signature.
If your engine has larger valves, a different cam, differences in ignition, differences in fuel pressure, has a different exhaust/muffler....it does not have the factory vacuum signature.
If your engine has low voltage...or a worn throttle plate with air seeping around it (and whose does not with a type 3)....you do not have the factory vacuum signature.
If you have the oil heated AAR and its less than absolutely perfect in function...you do not have the factory vacuum signature.
The MPS was set up based around a NEW engine vacuum signature. Yes...it has some variance range to paper over that....but its a narrow range.
Add to that....any variances in TS-1 and/or TS-2 and/or harness resistance......and you do not have the factory vacuum signature.
If any of the above applies to your engine....unless you are going to fix all of that....just adjust the damn MPS to fit the new vacuum signature.
I agree in principle...make sure the TS-1 and TS-2 are nominal. But outside of making sure the range is correct and they consistently do the same thing....just adjust the MPS. Ray |
I understand what you are saying. My original MPS worked until I screwed with the adjustment. When I rebuilt the engine in 97 and it now has 36,000 on it it ran fine even with the same type of MPS yet it was not the proper part number it still ran fine until 2009 and all I did was injector seals and fuel lines and put the heat exchangers back on and changed the plugs right after that it began this garbage. That was why I joined Samba to see if I could find answers.
How am I to know if I did try to adjust the MPS if it's to rich or to lean ? Plus this MPS has a hex adjustment screw so it needs to be open since this is the place it allows the MPS to see pressure change it does not have the full load stop just one adjustment so I need a hollow hex key . That chart posted in this post if correct tells me my air temp sensor is to high in ohm via temp so by plugging it in I may very well be making it even richer and I don't know if it is running lean or rich now , I suspect rich because the old spark plugs were dry black sooty and the fuel millage is not good. Yet I keep reading you can't go by the plugs these days.
I just don't want to make things worse and for all I know the crappy fuel we have might be the reason things changed . It does not have the stock exhaust hasn't since 95 yet that didn't make it run worse it ran the same and it ran great. Don't you think it's possible the really old head temp sensor might be starting to rich and dropping to fast . We only have at best 50 degree temp change winter to summer and it acts the same way all year round.
One thing I want to add. I placed a vacuum gauge teed into the MPS line , when I plug in the air temp sensor the vacuum rises and falls once I unplug it the vacuum is steady so it does affect the MPS vacuum quite a bit the rise and fall is screwing with the vacuum the MPS reads. |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Wed Aug 21, 2019 2:58 pm Post subject: Re: FI HTS ? |
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found this chart
I checked the TS1 or air temp sensor @88*F it reads 230 ohm so by this chart it's within spec.
TS2 in the car now reads 1994 ohm by the chart it's above what it should be checked the new one same temp and it is within spec if the chart is correct.
Doesn't really solve the issue, what it does is tell me the old TS2 is telling the ECU the engine is colder than it really is. Also TS2 read at near the same temp at least within 10 degrees now reads 1994 ohm and before it read 2270 ohm so it seems to change at close to the same temp reading . Has anyone had one that changed resistance at near the same temp?
This web site does show the VW part numbers that should be on these cars along with the chart.
Link to web page
http://bowlsby.net/914/Classic/zTN_Man13.pdf |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Wed Aug 21, 2019 4:26 pm Post subject: Re: FI HTS ? |
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| blues90 wrote: |
found this chart
I checked the TS1 or air temp sensor @88*F it reads 230 ohm so by this chart it's within spec.
TS2 in the car now reads 1994 ohm by the chart it's above what it should be checked the new one same temp and it is within spec if the chart is correct.
Doesn't really solve the issue, what it does is tell me the old TS2 is telling the ECU the engine is colder than it really is. Also TS2 read at near the same temp at least within 10 degrees now reads 1994 ohm and before it read 2270 ohm so it seems to change at close to the same temp reading . Has anyone had one that changed resistance at near the same temp?
This web site does show the VW part numbers that should be on these cars along with the chart.
Link to web page
http://bowlsby.net/914/Classic/zTN_Man13.pdf |
Yes....I have had many at or near that same temp...and yes...they all change a little with age...and no...its not really that important.
And...unless you are using a REALLY good meter with perfect connections...your reading can vary a bit. Remember this is a resistance to ground.
How well the sensor is grounded through its threads...and how well your meter is grounded to the head...changes the reading. The quality of the connection to the harness and teh quality of the connector matters a bit too.
I say its not really that important...because the ECU does not really have the resolution to adjust that fine. Its not supposed to be a "linear" gradation where the ECU sees a one ohm change and gives it another .001% tweak of fuel enrichment.
Also I have replaced the TS-2 before...with a simple potentiometer and just going in 200 ohms steps over 7-8 minutes...eventually arriving at about 150 ohms and normal running...the engine does not know the difference.
Also....for the sake of argument...lets say it really is a smooth linear graph line. Lets say that you have a range of 100 ohms to 2300 ohms and the ECU gives you 10% more fuel between 2300 and 100. That means that every 230 ohms you get 1% more fuel reduction.......do you ...should you....expect even, smooth running from this?
Let me tell you why you can't get smooth or rough running from this factor alone.
The #1 reason....its only 10% of the total fuel mixture. The other 90% is made up of the baseline of the fuel mixture adjustment from the MPS. The TS-1 is another 10%. The TVS or full load switch...can be a whopping 10-15% EXTRA...any time its activated....and a vacuum leak or AAR being open can mean another 10-20% extra......and the TS-2 has no control of any of that. They can happen right in the middle of that nice smooth linear transition.
And...if your MPS is adjusted wrong...say by 10%....that means the fuel given at any point in that nice smooth transition from theTS-2...is already 10% too rich or lean at any given ohm reading.
Back to the MPS.
You either have the early A MPS with a slotted screwdriver adjustment from teh outside and no diaphragm.....or a B series MPS with the outside allen key...which does not require a hollow allen key to adjust because you adjust it and then pull teh key out and test drive. Or you have a C or later E that uses both a hollow allen key to hold the bushing still while you adjust the diaphragm with a slotted screwdriver and you also do not leave the key or screwdriver in in.
How do you tell if its lean or rich?....turning the screw in is lean and out is rich to start with. Go in 1/8th or 1/10th increments at a time.
I keep telling people this but they just have not worked on D-jet enough to understand.
For the most part you do not need a wide band or sniffer unless you are doing very fine tuning and its near impossible to do on the stock muffler unless you have a bung welded in in just the right position or an old school probe that goes about 16" up the exhaust pipe.
Unless your MPS is grossly off like just after a bench calibration or when slaving a different part # in....you can pretty much get basic adjustment done like tuning a single barrel carb by ear.
1. find out what your TS-1 and Ts-2 maxes out to in perfect weather. Then disconnect them and install a fixed resistor at that ohms level...so changing resistance while test driving and tuning do not get you chasing fuel mixture.
2. Make sure its fully tuned...timing, idle and valve adjustment
3. Tweak it, drive it on a set coarse...and keep an eye on head and oil temps.
4. Tweak it until it runs the best and smoothest and has normal idle. You are usually 98% of the way there at this point.
5. Let it cool off. Then re-start it. Does it act or smell lean or rich? Give it a quick...very small tweak in either direction you think it needs it. Then let it cool down completely...test for restart.
Keep an eye on time and ambient conditions. If the weather or ambient heat changes radically...wait until tomorrow.
The key is to get it starting normally....and get it driving its best. Then if needed ...tweak it back or forward...maybe a 10th of a turn...until it runs cool and starts and shifts well.
Tune the MPS for PERFORMANCE first. Then start checking the exhaust.
The problem is that using an exhaust probe on these engines was never really done except at idle. With whats going on inside of the muffler thats all you can really do.
And...generally if it was running well and staying cool and the idle mixture shows OK on a long probe type sniffer....thats pretty much on for factory tuning.
People say...thats not accurate....and I say in response...."and ignoring the fact that the MPS needs SOME adjustment and instead swapping MPS after MPS in and out looking for a different result from an engine that no longer has a factory vacuum signature IS an accurate method?
Yes...actually...if you have made sure everything PHYSICAL is right...plugs, no vacuum leaks, compression, valve adjustment, wiring harness, ignition, timing and advance, voltage, fuel pressure and stability....and then you start this process....getting to run its best with the MpS when the sensors are fixed....is pretty damn spot on. Ray |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Wed Aug 21, 2019 7:36 pm Post subject: Re: FI HTS ? |
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Ray ;
My meter is accurate and I have two they agree , took the reading on the head and the sensor body and to ground all read the same.
I don't know what to say , sounds like a lot of testing and driving. That's not something very easy to do here. Perhaps I could drive to all the junk yards to see if I can find an original carb setup and see if i can fine tune this thing before I find them and which one wins.
Just kidding, not about driving around here , it's insane here. I'm just going to try the new head temp sensor just to see if it has any affect hoping better then go from there.
It may be true that the ECU does not see all the ohm input from the temp sensors yet since my HTS reads a different ohm reading at the same temp then something has to be wrong with it . I know the sensors ohms are on a curve per temp . I just have to at least try to see if the new one changes anything. I also need to clean the PCV and make a new gasket since now the 2 cap breather is movable with all the work I did trying to get the PCV to IAD hose off and the new one on. I've done everything else. Might go back to points since the pertronix is now 23 years old and I was told by pertronix they can fail not only by not working yet can also cause a miss besides since the condenser mounts on the left side on one of the vacuum can screws I don't want to be pulling the dist out on the side of the road here which is the only way to get at that screw . |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Thu Aug 22, 2019 2:59 pm Post subject: Re: FI HTS ? |
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| blues90 wrote: |
Ray ;
My meter is accurate and I have two they agree , took the reading on the head and the sensor body and to ground all read the same.
I don't know what to say , sounds like a lot of testing and driving. That's not something very easy to do here. Perhaps I could drive to all the junk yards to see if I can find an original carb setup and see if i can fine tune this thing before I find them and which one wins.
Just kidding, not about driving around here , it's insane here. I'm just going to try the new head temp sensor just to see if it has any affect hoping better then go from there.
It may be true that the ECU does not see all the ohm input from the temp sensors yet since my HTS reads a different ohm reading at the same temp then something has to be wrong with it . I know the sensors ohms are on a curve per temp . I just have to at least try to see if the new one changes anything. I also need to clean the PCV and make a new gasket since now the 2 cap breather is movable with all the work I did trying to get the PCV to IAD hose off and the new one on. I've done everything else. Might go back to points since the pertronix is now 23 years old and I was told by pertronix they can fail not only by not working yet can also cause a miss besides since the condenser mounts on the left side on one of the vacuum can screws I don't want to be pulling the dist out on the side of the road here which is the only way to get at that screw . |
Oh for sure! There ia w nough differene in CHTs just buying 10 of the same thing. Its worth while to swap one in and see if it helps.
Also....for what seems to be messing with yours....you MIGHT try one of the factory extenders for the TS-2. It will not really prevent it from dropping down to where its gokng to drop in ohms.....but it greatly slows it down.....like 2-3X slower warm up on the CHT.
That with a ballast resistor may fix everything for you.
Driving and adjusting is not actually that hard. Set up for it....pick a route with some stop and go and a mile or so of 45 mph or higher.....and you can finish it quick like an hour or so or do it over a few days. Ray |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Thu Aug 22, 2019 5:49 pm Post subject: Re: FI HTS ? |
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| raygreenwood wrote: |
| blues90 wrote: |
Ray ;
My meter is accurate and I have two they agree , took the reading on the head and the sensor body and to ground all read the same.
I don't know what to say , sounds like a lot of testing and driving. That's not something very easy to do here. Perhaps I could drive to all the junk yards to see if I can find an original carb setup and see if i can fine tune this thing before I find them and which one wins.
Just kidding, not about driving around here , it's insane here. I'm just going to try the new head temp sensor just to see if it has any affect hoping better then go from there.
It may be true that the ECU does not see all the ohm input from the temp sensors yet since my HTS reads a different ohm reading at the same temp then something has to be wrong with it . I know the sensors ohms are on a curve per temp . I just have to at least try to see if the new one changes anything. I also need to clean the PCV and make a new gasket since now the 2 cap breather is movable with all the work I did trying to get the PCV to IAD hose off and the new one on. I've done everything else. Might go back to points since the pertronix is now 23 years old and I was told by pertronix they can fail not only by not working yet can also cause a miss besides since the condenser mounts on the left side on one of the vacuum can screws I don't want to be pulling the dist out on the side of the road here which is the only way to get at that screw . |
Oh for sure! There ia w nough differene in CHTs just buying 10 of the same thing. Its worth while to swap one in and see if it helps.
Also....for what seems to be messing with yours....you MIGHT try one of the factory extenders for the TS-2. It will not really prevent it from dropping down to where its gokng to drop in ohms.....but it greatly slows it down.....like 2-3X slower warm up on the CHT.
That with a ballast resistor may fix everything for you.
Driving and adjusting is not actually that hard. Set up for it....pick a route with some stop and go and a mile or so of 45 mph or higher.....and you can finish it quick like an hour or so or do it over a few days. Ray |
I've tried a ballast resistor , even a variable pot at least with the CHT on this car. It didn't help , I know it's supposed to keep the temp sensor from dropping to low yet mine already starts out to high and as I said at the same temps it reads higher and lower after a drive then I let it cool down 24 hours or more take reading yesterday and it was almost 800 ohms less . I didn't catch this before , I would just take a reading to see what it read never did it 2 days in a row . I recall changing it with another I had in the car when I was fighting this in 2009 and the one in the car now helped some I checked that one I removed back then reads over 3000 ohm at 80*F they are not the same bosch number yet are both used in a T3 . Two are Bosch 003 and this one 012. None of the ones available now are Bosch the one I got is what VW said was the proper # 311 906 041A Ero parts makes it it reads what it should and from the way the car runs after starting cold it seems to rich and I say this because once 2 minutes pass I know the ohms have dropped and it runs better. Still runs worse with the air temp plugged in yet it runs better when first started with the air temp plugged in until the HTC dives it's about a 2 minute window. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Thu Aug 22, 2019 7:28 pm Post subject: Re: FI HTS ? |
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| blues90 wrote: |
| raygreenwood wrote: |
| blues90 wrote: |
Ray ;
My meter is accurate and I have two they agree , took the reading on the head and the sensor body and to ground all read the same.
I don't know what to say , sounds like a lot of testing and driving. That's not something very easy to do here. Perhaps I could drive to all the junk yards to see if I can find an original carb setup and see if i can fine tune this thing before I find them and which one wins.
Just kidding, not about driving around here , it's insane here. I'm just going to try the new head temp sensor just to see if it has any affect hoping better then go from there.
It may be true that the ECU does not see all the ohm input from the temp sensors yet since my HTS reads a different ohm reading at the same temp then something has to be wrong with it . I know the sensors ohms are on a curve per temp . I just have to at least try to see if the new one changes anything. I also need to clean the PCV and make a new gasket since now the 2 cap breather is movable with all the work I did trying to get the PCV to IAD hose off and the new one on. I've done everything else. Might go back to points since the pertronix is now 23 years old and I was told by pertronix they can fail not only by not working yet can also cause a miss besides since the condenser mounts on the left side on one of the vacuum can screws I don't want to be pulling the dist out on the side of the road here which is the only way to get at that screw . |
Oh for sure! There ia w nough differene in CHTs just buying 10 of the same thing. Its worth while to swap one in and see if it helps.
Also....for what seems to be messing with yours....you MIGHT try one of the factory extenders for the TS-2. It will not really prevent it from dropping down to where its gokng to drop in ohms.....but it greatly slows it down.....like 2-3X slower warm up on the CHT.
That with a ballast resistor may fix everything for you.
Driving and adjusting is not actually that hard. Set up for it....pick a route with some stop and go and a mile or so of 45 mph or higher.....and you can finish it quick like an hour or so or do it over a few days. Ray |
I've tried a ballast resistor , even a variable pot at least with the CHT on this car. It didn't help , I know it's supposed to keep the temp sensor from dropping to low yet mine already starts out to high and as I said at the same temps it reads higher and lower after a drive then I let it cool down 24 hours or more take reading yesterday and it was almost 800 ohms less . I didn't catch this before , I would just take a reading to see what it read never did it 2 days in a row . I recall changing it with another I had in the car when I was fighting this in 2009 and the one in the car now helped some I checked that one I removed back then reads over 3000 ohm at 80*F they are not the same bosch number yet are both used in a T3 . Two are Bosch 003 and this one 012. None of the ones available now are Bosch the one I got is what VW said was the proper # 311 906 041A Ero parts makes it it reads what it should and from the way the car runs after starting cold it seems to rich and I say this because once 2 minutes pass I know the ohms have dropped and it runs better. Still runs worse with the air temp plugged in yet it runs better when first started with the air temp plugged in until the HTC dives it's about a 2 minute window. |
If 200 ohms ballast makes it run poorly even when cold....and even if 3000 makes it run poorly even if it starts well enough...thats overall fuel mixture being off....MPS.
There is one quick and simpler way to tell which way to go. I do not recommend driving this far in this condition....but put in the the best CHT you have.
Before you start the experiment....with a GOOD gauge....dial the fuel pressure back 3 psi. That reduces available fuel across the whole range by 10.71% (at 28 psi its right at 3.57% per 1 psi of fuel pressure).
Start the car stone cold and see how that drives. You will get a little less atomization at 25 psi but it should run fine. See if it warms up normally and drives smoother.
If it does....the answer is NOT to keep it with fuel pressure too low...but to tweak the MPS. Ray |
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