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KTPhil
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Joined: April 06, 2006
Posts: 15905
Location: SoCal
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 Posted: Wed Mar 03, 2010 5:32 pm Post subject: |
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| Russ, do you have the test chart from the Bentley or Bosch manual scanned in your gallery/website? That would help him get started testing. |
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Russ Wolfe
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Joined: October 08, 2004
Posts: 25689
Location: Central Iowa
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| Posted: Wed Mar 03, 2010 5:38 pm Post subject: |
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Should be there someplace.
In the FI section.
I have been moving some stuff around lately. Trying to get the site a little more organized.
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Wed Mar 03, 2010 8:59 pm Post subject: |
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| KTPhil wrote: |
Do you have a manual? It should tell you how to check the two temp sensors, the throttle valve switch (TVS), and the manifold pressure sensor (MPS). It's not hard, but little things like temperature, whether the wires are connected or not when you test, etc. make all the difference in getting a correct reading, and not damaging the meter.
Best for this is a Bentley manual (brown for your year). |
Yes i do have my bentey manual  . And i got out the multimeter and theres something wrong with it, its old and doesnt want to work right. sooo... tomorow after school ill go to my FLAPS and see if they have one and then ill report back with some numbers.
Thanks |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Thu Mar 04, 2010 3:07 pm Post subject: |
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Ok, so i got a cheap multimeter today and i got some numbers however i dont really know how accurate it is. Im no electrician so its all a litttle confusing to me, everything was a little jumpy so it was hard to get a constant reading. This is what i found.
Temp sensor 2=133ohms?
Injectors=all read about 3ohms.
Pressure switch jumped too much to tell, as did the throttle valve switch.
Manifold pressure sensor=75 ohms?
Keep in mind this is with a warm engine.
And does anyone have tips for using a multimeter? Maybe i was using it wrong. The directions that came with it were not helpful at all.
Thanks |
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KTPhil
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Joined: April 06, 2006
Posts: 15905
Location: SoCal
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| Posted: Thu Mar 04, 2010 3:11 pm Post subject: |
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Power OFF for all resistnce measurements.
Unplug all conenctors of any device you are mesauring the resistance of.
Pay attention to the scale of the meter to correctly measure resistance.
If your measurements are jumpy, then either your connections to the meter or device are bad, or the device is damaged internally.
Despite all the wrong EFI information in Muir, his VOM troubleshooting steps are pretty well laid out. He gives a little tutorial on the VOM. Digital VOMs don't need zeroing, however. If your are e VOM novice, use Muir, not Bentley. |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Thu Mar 04, 2010 6:42 pm Post subject: |
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| KTPhil wrote: |
Power OFF for all resistnce measurements.
Unplug all conenctors of any device you are mesauring the resistance of.
Pay attention to the scale of the meter to correctly measure resistance.
If your measurements are jumpy, then either your connections to the meter or device are bad, or the device is damaged internally.
Despite all the wrong EFI information in Muir, his VOM troubleshooting steps are pretty well laid out. He gives a little tutorial on the VOM. Digital VOMs don't need zeroing, however. If your are e VOM novice, use Muir, not Bentley. |
Ok, so i read in the muir book and got a little more understanding of what im doing. I was able to get constant readings but i did'nt know what they ment so i took pictures of the meter on variouse objects i hope this helps.
This is at one of the injectors (its 02.8 if its hard to tell) they all read about the same. These pictures are with the engine warm, and the meter set up to ohms/con and the dial set to 200.
Next is 00.3 at the pressure switch (behind the right intake runners)
This is at temp sensor 2, it reads 147.9
Next is 00.2 at the throttle valve switch (right side of throttle body)
Finally is 94.3 at the manifold pressure sensor.
So these readings seem right? Again this is with the meter set at the 200 mark on the dial with the wires set at ohms and con.
And the engine was warm. I hope this helps.Thanks |
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raygreenwood
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Joined: November 24, 2008
Posts: 4980
Location: Des moines Iowa
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| Posted: Fri Mar 05, 2010 8:32 am Post subject: |
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A couple of things. Its worth it to right down what the readings are supposed to be. Then hook up the meter and read the part while you dial through teh range gates on the meter until you get the decimal points in the right place.
Next....forget the resistance reading of the throttle valve switch. There is nothing to read other than continuity...meaning does the switch open and close properly (on/off) and do all of the contact wipers cause an "on" function as the wiper arms slides over them.
The books are confusing people.....because the throttle valve switch is NOT a resistance based unit at all. Its just a switch. The resistance check is just to make sure that the resistance in the TVS...is not insanely high ....which usually denotes corrosion....which you can generally see anyway.
Do not hold either the sensor one or 2 in your hands while checking. They are that sensitive. Just your body heat causes a constant rate of drop in resistance.
The proper way to do this type of checking is to get a pair of clean female connectors that are removed from an old fuel injection harness plug....with about 2-3" of wire on the back of each connector. Crimp on one of the red butt connectors you find at radio shack. You will now find that teh pins on the ends of the probes from your volt meter will fit snugly in the ends of these butt connectors. Or you can crimp on small gator clips from radio shack.
The gist is that you need to connect up the meter, lay the temp sensors on a table and let them come to a stable temperature....then measure. Throw them in the freezer later and check the cold range (max resistance) then put them in the edge of a pot of boiling water to see lowest resistance range.
On the MPS....you need to measure the inner pair of the four pins and then the outer pair. record that. Roughly 98 ohms for one and about 300 for the other pair...IIRC.
The CHT at 70-80F will be about 2300 0hms give or take.
Also important is the resistance of the trigger points. Reagardless of what any book tells you....about 1.2 ohms is max on either trigger pair. And....the two triggers should be within about .2 ohms of each other. Here are some examples of what acceptable in trigger resistance:
Acceptable 1.2 ohms and 1.2 ohms (maxed out but balanced) the max range of variation would be a reading of 1.2ohms and 1.0 ohms
Good 1.0 ohms and 1.0 ohms (high but balanced and some room to age) max deviation readings would be like 1.0 to 1.2 or 1.0 to .8 ohms.
very good: .8 ohms and .8 ohms with max deviations of 1.0 and .8 ohms or .8 and .6 ohms.
Excellent: anything below .8 ohms and with both trigger pairs within .2 ohms of each other.
Also from what I remember...the presure switch is an on off diaphram unit switch...and NOT a variable resistance based switch. Please correct me if I'm wrong...but its just a switch. Ray |
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Russ Wolfe
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Joined: October 08, 2004
Posts: 25689
Location: Central Iowa
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| Posted: Fri Mar 05, 2010 9:49 am Post subject: |
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Yes, it is just a switch.
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Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey
Gary: OK. Ima poop. |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Sat Mar 06, 2010 2:37 pm Post subject: |
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| raygreenwood wrote: |
A couple of things. Its worth it to right down what the readings are supposed to be. Then hook up the meter and read the part while you dial through teh range gates on the meter until you get the decimal points in the right place.
Next....forget the resistance reading of the throttle valve switch. There is nothing to read other than continuity...meaning does the switch open and close properly (on/off) and do all of the contact wipers cause an "on" function as the wiper arms slides over them.
The books are confusing people.....because the throttle valve switch is NOT a resistance based unit at all. Its just a switch. The resistance check is just to make sure that the resistance in the TVS...is not insanely high ....which usually denotes corrosion....which you can generally see anyway.
Do not hold either the sensor one or 2 in your hands while checking. They are that sensitive. Just your body heat causes a constant rate of drop in resistance.
The proper way to do this type of checking is to get a pair of clean female connectors that are removed from an old fuel injection harness plug....with about 2-3" of wire on the back of each connector. Crimp on one of the red butt connectors you find at radio shack. You will now find that teh pins on the ends of the probes from your volt meter will fit snugly in the ends of these butt connectors. Or you can crimp on small gator clips from radio shack.
The gist is that you need to connect up the meter, lay the temp sensors on a table and let them come to a stable temperature....then measure. Throw them in the freezer later and check the cold range (max resistance) then put them in the edge of a pot of boiling water to see lowest resistance range.
On the MPS....you need to measure the inner pair of the four pins and then the outer pair. record that. Roughly 98 ohms for one and about 300 for the other pair...IIRC.
The CHT at 70-80F will be about 2300 0hms give or take.
Also important is the resistance of the trigger points. Reagardless of what any book tells you....about 1.2 ohms is max on either trigger pair. And....the two triggers should be within about .2 ohms of each other. Here are some examples of what acceptable in trigger resistance:
Acceptable 1.2 ohms and 1.2 ohms (maxed out but balanced) the max range of variation would be a reading of 1.2ohms and 1.0 ohms
Good 1.0 ohms and 1.0 ohms (high but balanced and some room to age) max deviation readings would be like 1.0 to 1.2 or 1.0 to .8 ohms.
very good: .8 ohms and .8 ohms with max deviations of 1.0 and .8 ohms or .8 and .6 ohms.
Excellent: anything below .8 ohms and with both trigger pairs within .2 ohms of each other.
Also from what I remember...the presure switch is an on off diaphram unit switch...and NOT a variable resistance based switch. Please correct me if I'm wrong...but its just a switch. Ray |
Ok, i got some new numbers today with a cold engine.
MPS=90ohms on the outer recepticles and 333 on the inner.
Crankcase Temperature sensor=530 ohms (shouldnt that be 300 ohms? So do i have a problem with this than?)
I also tried for the head temp sensor but unless im blind i couldnt find it where the book said it was. So i havent got that number yet. However is it possible that the crankcase temp sensor could be causing my cold start idle problems?
Thanks Again. |
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raygreenwood
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Joined: November 24, 2008
Posts: 4980
Location: Des moines Iowa
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| Posted: Sat Mar 06, 2010 3:55 pm Post subject: |
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Yes...unplug it and try again. I have found that about 50% of all D-jet vehciles either run factroy perfect with a good intake air temp sensor...or in one season or another....either very hot or moderatly cold....they run best in a particuolar season with the sensor disconnected. Don't worry, it simply causes a default setting. The sensor itself gives a range of 5-15% enrichment across the board as resistance is up.
The ECU has a range limit.....can't remember...but I think my engine quit reacting to the input at 800-1200 ohms.
It could be making you overly rich...and if your system runs slightly rich due to other reasons (fuel pressure, CHT, MPS setting or wiring resistances here and there).....it may be too rich to start. Ray |
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JSMskater
Samba Grease Gorilla
Joined: February 01, 2006
Posts: 5211
Location: Las Cruces NM
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| Posted: Sat Mar 06, 2010 4:17 pm Post subject: |
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just fyi people -- I asked Ev to add this link to the advanced FI sticky so it isn't lost. Ray has a lot of good info here 
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Wed Mar 10, 2010 5:12 pm Post subject: |
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This sounds stupid but i cant find the head temp sensor. According to the book its under the exhaust port on the drivers side head by cylinder 4, and i just dont see anything. Is it under the tin? How do i get to it. Does anyone have a picture?
Thanks |
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KTPhil
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Joined: April 06, 2006
Posts: 15905
Location: SoCal
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| Posted: Wed Mar 10, 2010 6:02 pm Post subject: |
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| It can also be located on top of the head. Look down near #4 cylinder from above, near the exhaust port. It screws straight down into the head. It is accessible through a 1" or so hole in the black tinware, maybe covered by a rubber plug/seal. A single wire comes out of it. It does not unplug from the sensor; there is a 6-12" pigtail wire coming out of the sensor leading to a connector-- unplug it there and then take a reading. |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Fri Mar 12, 2010 7:58 pm Post subject: |
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| KTPhil wrote: |
| It can also be located on top of the head. Look down near #4 cylinder from above, near the exhaust port. It screws straight down into the head. It is accessible through a 1" or so hole in the black tinware, maybe covered by a rubber plug/seal. A single wire comes out of it. It does not unplug from the sensor; there is a 6-12" pigtail wire coming out of the sensor leading to a connector-- unplug it there and then take a reading. |
So i found the head temp sensor and took it out and it looked really old and had like build up so i just decided to replace it. I got a new one today and installed it and the car does seem to run a little better. Next i think i need to check the fuel pressure. I dont have a fuel pressure gauge but instead of buying one i read in another thread that you can make one.
| Quote: |
| YOU NEED A FUEL PRESSURE GAUGE. don't rely on "feel". put the fuel pressure gauge on the T between the injectors, start the engine, and let it idle. then make the adjustment while watching the gauge. if you dont have a gauge you can make one at home depot for less than 15 bucks. using a regular water heater gauge and a brass nipple fitting. |
Does anyone have anymore insight on doing this? |
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Bobnotch
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Joined: July 06, 2003
Posts: 10694
Location: Kimball, Mi
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| Posted: Fri Mar 12, 2010 8:33 pm Post subject: |
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| volksjunky41 wrote: |
| KTPhil wrote: |
YOU NEED A FUEL PRESSURE GAUGE. don't rely on "feel". put the fuel pressure gauge on the T between the injectors, start the engine, and let it idle. then make the adjustment while watching the gauge. if you dont have a gauge you can make one at home depot for less than 15 bucks. using a regular water heater gauge and a brass nipple fitting. |
Does anyone have anymore insight on doing this? |
Yeah. I used a gauge type tire pressure gauge (made in china, and all brass), with a max of 60 psi from Tractor Supply Company that I paid 5 bucks for. I also picked up an 1/8th inch pipe coupler ($2), and a 1/8th inch large hose barb ($2). I used teflon tape on the threads, and screwed them all together, after I removed the tire portion of the tire gauge. I then added a piece of 5/16ths fuel hose and 2 screw drive clamps ($1). My fuel pressure testing gauge is complete, and it cost me about 10 bucks with the hose clamps.
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Sat Mar 13, 2010 6:48 pm Post subject: |
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| Bobnotch wrote: |
| volksjunky41 wrote: |
| KTPhil wrote: |
YOU NEED A FUEL PRESSURE GAUGE. don't rely on "feel". put the fuel pressure gauge on the T between the injectors, start the engine, and let it idle. then make the adjustment while watching the gauge. if you dont have a gauge you can make one at home depot for less than 15 bucks. using a regular water heater gauge and a brass nipple fitting. |
Does anyone have anymore insight on doing this? |
Yeah. I used a gauge type tire pressure gauge (made in china, and all brass), with a max of 60 psi from Tractor Supply Company that I paid 5 bucks for. I also picked up an 1/8th inch pipe coupler ($2), and a 1/8th inch large hose barb ($2). I used teflon tape on the threads, and screwed them all together, after I removed the tire portion of the tire gauge. I then added a piece of 5/16ths fuel hose and 2 screw drive clamps ($1). My fuel pressure testing gauge is complete, and it cost me about 10 bucks with the hose clamps. |
So today i was able to make a fuel pressure gauge using the gauge from a compressor paint spray gun and connected it there to the fitting between the injectors 1 and 2 and it shot right to 30 when the car started and stayed nice and steady, so fuel pressure seems to be in check. Also, the other day when i was at the vw shop getting my new head temp sensor i told the guy working there about my problem and he suggested checking the dwell at the points and not just the gap. Is there a way to do this without a tach/dwell meter like the muir book and bentley say to do. What exactly is the dwell? I know its measured in degrees but thats about it  .
Thanks |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Sat Mar 13, 2010 6:59 pm Post subject: |
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| Quote: |
You can test dwell with just a test lamp and a degree scale. On Type 3 engines it is a pita. But for the record, turn on the ignition and put your test light on the (-) of the coil and a ground. Rotate the engine until the light comes on and rotate until it just goes out (it does not matter which cylinder happens to be up at-bat). Make a reference mark to show where the crank pulley was, and rotate the engine until the light just comes on again. Divide the number of degrees the pulley turned by 2 and that thar's yer poor man's dwell. VW gives a generous range, shoot for 45* dwell (the optimum theoretical dwell) and you will have longer intervals between point adjustments.
Colin |
I just found this in another thread. However i dont have a degree scale on my pulley. What could i try?
Thanks |
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Russ Wolfe
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Joined: October 08, 2004
Posts: 25689
Location: Central Iowa
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| Posted: Sat Mar 13, 2010 7:13 pm Post subject: |
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That will not show you the dwell with the engine running. If you have a worn distirbutor, or worn breaker plate, etc.
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Gary: OK. Ima poop. |
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RyanRodman
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Joined: February 07, 2009
Posts: 443
Location: Gig Harbor, Wa
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| Posted: Sun Mar 14, 2010 7:30 pm Post subject: |
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| Russ Wolfe wrote: |
| That will not show you the dwell with the engine running. If you have a worn distirbutor, or worn breaker plate, etc. |
Do you think dwell is even something of concern? If the dwell is way off is it possible to cause such symptons as mine? |
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Russ Wolfe
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Joined: October 08, 2004
Posts: 25689
Location: Central Iowa
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| Posted: Sun Mar 14, 2010 8:23 pm Post subject: |
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If the breaker plate is worn in the distributor, the engine will not run right. But it may show up more when the engine is cold.
http://shop.ebay.com/?_from=R40&_trksid=p3907....Categories
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