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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22728
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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 Posted: Fri Jun 13, 2014 6:05 pm Post subject: Re: Misc. FI Issues |
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| tomf51 wrote: |
I have a '70 Squareback with FI and many issues seem to be turning up. I have gone thru all the checking values at the ECU plug an everything seems ok. Two oddball issues: 1, the MPS is an 051B and I believe its should be a "C" ( ECU is 021D ), and 2, I am only getting about 27 psi of fuel because I have a non-adjustable regulator. All of my current problems are when fully warmed-up, no power under load and occasional loud backfire. Any ideas?
Also, every time i look at it crosswise a wire will break at one of the connectors. I would like to rewire the harness but can't find where to source the ferrules (?) inside the connectors. Are they available?
Thanks |
Yes, your MAP should be a "C". If your car is a 1970, your ECU should be a C as well. If your regulator is non adjustable, you have the wrong regulator.
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tomf51
Samba Member
Joined: April 21, 2011
Posts: 34
Location: Calif.
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| Posted: Fri Jun 13, 2014 8:42 pm Post subject: |
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| Thanks, Tram. I was looking at the chart on the previous page and it shows 2 columns for the ECU. What is the diff between production number and part number? I have a correct regulator on order, but out of curiosity can pressure that is only 27 or even 26 psi cause issues? |
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Tram
Samba Socialist
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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: Fri Jun 13, 2014 9:51 pm Post subject: |
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| tomf51 wrote: |
| Thanks, Tram. I was looking at the chart on the previous page and it shows 2 columns for the ECU. What is the diff between production number and part number? I have a correct regulator on order, but out of curiosity can pressure that is only 27 or even 26 psi cause issues? |
Anything that's not right will cause issues. I'd be checking your temp sender resistance, though.
A big problem you are fighting is that your B MAP is meant to be used in concert with the A/B system pressure switch, which richens the mixture under partial and full load. The C and D MAP has that feature built into it and those systems eliminate the pressure switch.
And yes, there WAS a "D" MAP sensor. These were the original MAPs on early '71 cars. They were replaced with C units per VW when a D failed- and most of the Ds failed prematurely. I can't remember exactly, but I think the copper diaphragm in the D, while more sensitive, was too fragile.
Can you post a pic of your non- adjustable pressure regulator?
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tomf51
Samba Member
Joined: April 21, 2011
Posts: 34
Location: Calif.
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| Posted: Fri Jun 13, 2014 10:36 pm Post subject: |
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I purchased a used "c" MAP sensor on Samba but hasn't yet arrived. I will take picture of the regulator when the new one gets here. I bought the old one from Rockauto, and it was listed as a proper replacement, but I didn't notice the problem til it arrived.
Is it possible that my "D" ECU is correct for a '70?
Also, I'm looking for a "C" TVS. Any suggestions for obtaining that? I have resoldered every wire in the one I have and the metal channels and zigzags appear kind of thrashed. |
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tomf51
Samba Member
Joined: April 21, 2011
Posts: 34
Location: Calif.
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| Posted: Fri Jun 13, 2014 10:39 pm Post subject: |
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| Oh yes, I forgot. The temp sensor(1) seems to be OK. |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22728
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Fri Jun 13, 2014 10:41 pm Post subject: |
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| tomf51 wrote: |
I purchased a used "c" MAP sensor on Samba but hasn't yet arrived. I will take picture of the regulator when the new one gets here. I bought the old one from Rockauto, and it was listed as a proper replacement, but I didn't notice the problem til it arrived.
Is it possible that my "D" ECU is correct for a '70?
Also, I'm looking for a "C" TVS. Any suggestions for obtaining that? I have resoldered every wire in the one I have and the metal channels and zigzags appear kind of thrashed. |
I may have one- I'll look. D ECU isn't correct for a '70, but it may work OK.
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tomf51
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Joined: April 21, 2011
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Location: Calif.
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| Posted: Fri Jun 13, 2014 11:22 pm Post subject: |
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| The car has had periods where it's run really well, but less so in the summer heat. I'm practically in the desert and 105 is not that uncommon. Most times when it starts to run crappy I find a broken wire somewhere and it clears right up. This time I've had to do the full on system check. |
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ziconylo
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Joined: November 20, 2006
Posts: 88
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| Posted: Sun Jun 15, 2014 10:36 pm Post subject: |
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| Tram wrote: |
| With the engine at full operating temperature, pull the hose to the AAR off the air cleaner and plug it. Now drive the car and report back. |
hi.
i have done the test. nothing really changed.
But.. i have cloggediad pipe at iad for pressure switch and left it connected so that he has reading of atmosphere pressure at the car ran like kitty a little bit rich on idle 11.9.
while riding it is 12.5 - 13.5 what is quite reasonable. i didnt notice bad performance.
so the question is what is faulty? i tried another switch and situation was same. when i connected hose to the pressure switch while engine was on and simulated vacumm it agains started to waveing looping afr showed from14 to 18 ratio in quite regular cycle. Symptopms like air leak. so when pressure switch measure air it is like off with resistance 0. while vacum is on the resistance is 1 and pressure switch is on.
suming up when switch is on the engine loops. |
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Tram
Samba Socialist
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| Posted: Mon Jun 16, 2014 12:02 am Post subject: |
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Is it possible that your MAP sensor is not holding vacuum?
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ziconylo
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| Posted: Mon Jun 16, 2014 10:08 pm Post subject: |
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| Tram wrote: |
| Is it possible that your MAP sensor is not holding vacuum? |
i dont know how to check it.
i have 3 mps one with no epoxy ant two sealed. i will do some trials with them. |
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Bobnotch
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Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Tue Jun 17, 2014 8:01 am Post subject: |
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| ziconylo wrote: |
| Tram wrote: |
| Is it possible that your MAP sensor is not holding vacuum? |
i dont know how to check it.
i have 3 mps one with no epoxy ant two sealed. i will do some trials with them. |
Hook it up to a hand held vacuum pump, put a little vacuum on it, and see if it holds. If it looses vacuum right away, then it leaks. Or put a clean hose on it, and suck on the hose. Use your tongue to cap the end of the hose and see if it holds vacuum. If it doesn't, then it leaks. You're basically testing it like checking the vac advance on the distributor. It's not rocket science. 
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71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
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| Tram wrote: |
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ziconylo
Samba Member
Joined: November 20, 2006
Posts: 88
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| Posted: Sat Jun 21, 2014 7:10 am Post subject: |
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| Bobnotch wrote: |
| ziconylo wrote: |
| Tram wrote: |
| Is it possible that your MAP sensor is not holding vacuum? |
i dont know how to check it.
i have 3 mps one with no epoxy ant two sealed. i will do some trials with them. |
Hook it up to a hand held vacuum pump, put a little vacuum on it, and see if it holds. If it looses vacuum right away, then it leaks. Or put a clean hose on it, and suck on the hose. Use your tongue to cap the end of the hose and see if it holds vacuum. If it doesn't, then it leaks. You're basically testing it like checking the vac advance on the distributor. It's not rocket science. |
hi,
none of my mps is leaking by simple test.
i have just order vacum pump and see if it keeps ca 20inHg for minutes. let you know later.
i f
dont have proper gauge to check resistance on port 8 and 10 while changing vacuum - can you recommend any?
situation now with pressure switch non connected to iad simulates the situation for full load for engine.
btw.
when i set mps for correct afr on warm, engine cannot work on this setting when cold.
best regards,
jakub |
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KTPhil 
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Posts: 34021
Location: Conejo Valley, CA
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| Posted: Sat Jun 21, 2014 11:32 am Post subject: |
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| ziconylo wrote: |
dont have proper gauge to check resistance on port 8 and 10 while changing vacuum - can you recommend any?
situation now with pressure switch non connected to iad simulates the situation for full load for engine. |
Resistance of the coils will not change with vacuum. Check resistance just to find opens or shorts. To check readings under vacuum you would need an inductance meter which most home hobbyists lack. But if it holds vacuum and does not show shorts or opens, then it would only be a matter of adjustment to get it right. But you have to learn a lot before adjusting-- lots of interactions and subtleties to it-- and you can do more damage than good. |
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Mike Fisher
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Joined: January 30, 2006
Posts: 17970
Location: Eugene, OR
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| Posted: Sat Jun 21, 2014 11:45 am Post subject: |
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Tram adjusts my MAP w/small screw driver & 02 sniffer clipped to my tailpipe. It doesn't look that complicated! 
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69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
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ziconylo
Samba Member
Joined: November 20, 2006
Posts: 88
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| Posted: Sat Jun 21, 2014 2:30 pm Post subject: |
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guys i would like to make electronic calibration using inductance gauge and vacuum pump like 914 peter anderds did
http://members.rennlist.com/pbanders/manifold_pressure_sensor.hor
do you have values or at least ratio of inductance between inHg '0'; '4' and '15' which reflects idle , part load and full load?
unfortunately he has values only for porshe mps.
mine mps is early with pressure switch. pressure switch took over full load signaling to ecu.
Last edited by ziconylo on Sat Jun 21, 2014 2:47 pm; edited 1 time in total |
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Mike Fisher
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Location: Eugene, OR
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| Posted: Sat Jun 21, 2014 2:33 pm Post subject: |
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Good luck with that! 
_________________
https://imgur.com/user/FisherSquareback/posts
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Sat Jun 21, 2014 8:26 pm Post subject: |
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| ziconylo wrote: |
guys i would like to make electronic calibration using inductance gauge and vacuum pump like 914 peter anderds did
http://members.rennlist.com/pbanders/manifold_pressure_sensor.hor
do you have values or at least ratio of inductance between inHg '0'; '4' and '15' which reflects idle , part load and full load?
unfortunately he has values only for porshe mps.
mine mps is early with pressure switch. pressure switch took over full load signaling to ecu. |
If you have the "A" or "B" (68-69), then the pressure switch just goes between NO, and NC on the contacts. The MPS is just there to tell the ECU you have vacuum. I've never adjusted the early type before, so I can't help you there. Maybe Tram can give you some insight on that set up. I do know that the early versions (68-69) were nearly built proof, and didn't need much adjusting, if any at all.  The big key with those is to make sure you have no vacuum leaks.
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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ziconylo
Samba Member
Joined: November 20, 2006
Posts: 88
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| Posted: Sun Jun 22, 2014 2:52 am Post subject: |
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Hi Tram
I appreciate your help with B MPS - this is mine http://images64.fotosik.pl/1101/cd036d69c8331e37.jpg
I saw in your gallery a picture of mps dissambled and you use hexagon wrench. Does it work for B ECU?, do I need to dissasemble MPS?.
The outer screw - - can i set proper setting with this screw? - I doubt - when I make setting at fully warm up I cannot start when cold on this mps setting. How to overcome that? How do you set with AFR? I have it so should be simplier.
do you have any link to instruction?
regards
jakub |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22728
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Sun Jun 22, 2014 9:52 am Post subject: |
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| ziconylo wrote: |
Hi Tram
I appreciate your help with B MPS - this is mine http://images64.fotosik.pl/1101/cd036d69c8331e37.jpg
I saw in your gallery a picture of mps dissambled and you use hexagon wrench. Does it work for B ECU?, do I need to dissasemble MPS?.
The outer screw - - can i set proper setting with this screw? - I doubt - when I make setting at fully warm up I cannot start when cold on this mps setting. How to overcome that? How do you set with AFR? I have it so should be simplier.
do you have any link to instruction?
regards
jakub |
Jakub, let's see what your spark plugs look like first.
If the car runs well hot, but won't run cold, either the mix is still off, or you have an issue with a temp sensor or auxiliary air regulator... assuming that you have zero vacuum leaks.
To answer your question, though, on the A/B system the single screw in the MPS is the only adjustment. Is yours sealed?
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| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
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ziconylo
Samba Member
Joined: November 20, 2006
Posts: 88
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| Posted: Sun Jun 22, 2014 1:54 pm Post subject: |
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| Tram wrote: |
| ziconylo wrote: |
Hi Tram
I appreciate your help with B MPS - this is mine http://images64.fotosik.pl/1101/cd036d69c8331e37.jpg
I saw in your gallery a picture of mps dissambled and you use hexagon wrench. Does it work for B ECU?, do I need to dissasemble MPS?.
The outer screw - - can i set proper setting with this screw? - I doubt - when I make setting at fully warm up I cannot start when cold on this mps setting. How to overcome that? How do you set with AFR? I have it so should be simplier.
do you have any link to instruction?
regards
jakub |
Jakub, let's see what your spark plugs look like first.
If the car runs well hot, but won't run cold, either the mix is still off, or you have an issue with a temp sensor or auxiliary air regulator... assuming that you have zero vacuum leaks.
To answer your question, though, on the A/B system the single screw in the MPS is the only adjustment. Is yours sealed? |
Ok, will check spark plugs at weekend. But I have real time afr monitoring the mixture so I know what is exact mixture. At pressure switch off I got mixture like in high load at 12 at idle and its got leaner on higher rpms to 13.5-14.
Also will tell you what is the mps vacumm behaviour when get vacuum pump. Also will check iad inHG while on idle.
i have 3 mps. 2 are sealed and one is not. I am experimenting on non sealed.
I dont expect vacuum leak on AAAR. I check it closed and it was same behaviour. When close throttle engine dies - so no leak on mainfold.
I expect that vacumm signage of engine has changed and I need to adjust it via mps. But I am suprised that when make setting at warm I cannot start cold.
Initial tests on pressure switch and MPS shows no leak. I will do it with vacuum pump as these are more accurate. |
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