No start - 91 Passat - Please help before I set it on fire

Sorry for the length of this post, but I want to make sure anyone interested in helping has all the information I have...

I have a 1991 Passat with 287K km on it. I've been having problems with it for some time. Used to be, it would start without a problem, however if I drove it any distance I ran the risk of stalling and not being able to start again. Let it sit a while, car starts. A friend of mine worked in a VW service department up to the late 80's and we tried to pinpoint the problem. Finally, we gave up and brought it to the local dealership. The computer said it has a bad oxygen sensor and bad knock sensors. C$500 for parts and at least 3 hours at C$70 for labour. And that was just to clear the ECU so they could diagnose the problem.

It ran worse than ever once it came out of their shop, even though they only hooked it up to the computer. I managed to limp my way home, but the car hasn't started since.

I don't understand how the oxygen sensor or knock sensors have anything to do with starting. It's my understanding that they only have an effect on a running engine. Both parts are quite expensive, so unless someone can explain how they effect starting, I'm not replacing either until the car starts :)

The car turns over just great (although I've had to recharge the battery a few times). The starter motor is good, I replaced it not too long ago. The car sounds like it's really trying to start. When I'm trying to start it, it often (but not always) sounds like it's firing on one cylinder. Sometimes, when I'm first starting to work on it, it will start but it only runs for a few seconds and very poorly.

I think I've fixed the oxygen sensor problem, the ground connector on the cable from the oxygen sensor to the ECU was broken. I cannot find any other circuits that are broken.

We've attempted to correct the previous problem by adjusting the airflow sensor plate. Since it's been stuck in the driveway, I've spent a lot of time adjusting it and trying to start the car (1/4 turn, try to start car, 1/4 turn, try to start car ...). So, that's probably right out of whack at this point.

I've had the ignition wires on and off more times than I can count, doing various checks that have been suggested to me. I'm not sure anymore if they are still in the right place. Here's how they are placed on the distributor cap now:

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Reply to
Laurence MacKenzie
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Same thing happened to me - maybe. I was sure I had bad gas. I drained the tank and it was still the same after a refill. I had someone crank it while I felt the sensor plate with the boot off and it started and ran fine! With the boot off - so it could sense no air. I had the boot in my hand saying to myself the car can't run this way. The cold start injector was running all the time I unplugged it and I had my passat back. Good luck! -chris

Reply to
chris

The cold start valve has been disconnected for a while, that was one of my first thoughts too. It's warm enough here (20+ celsius) that it shouldn't operate anyways. I've also replaced the fuel with premium (93 octane) fuel from a reliable gas station.

I did try tak>Same thing happened to me - maybe.

Reply to
Laurence MacKenzie

check for air leaks , do you hear the fuel pump make noises for a second,when you turn on the key? it is the one under the car on the left side (I think) look and feel for vibration while some one turns over the engine. there may be a poor contact in the fuse panel-fuses #15 & #18 - If you can smell raw gass at the exhaust after cranking a while, the engine is flooding: leaking injectors good luck, karl

Reply to
Karl D.

Checked again for air leaks. Couldn't find any, followed vacuum lines all around car, re-checked boot and breather hoses. No problems. Is there somewhere in particular that's prone to problems that I should take a closer look at?

I thought I could smell fuel at the tailpipe, so I pulled the injectors and ran some of the fuel delivery tests in the Bentley book. Fuel is coming out of all injectors in an even cone-shaped pattern when the sensor plate is lifted. Fuel stops coming out when the sensor is dropped. The fuel comes out of each injector in equal amounts..

So the fuel pump is working. I don't know if it's delivering the right amount of fuel ... my high-tech fuel-measuring equipment consists of four empty Corona bottles ('cause they're clear) and some duct tape. Can't tell I'm Canadian, eh!? If anyone figures it's worth it, I can mark the bottles and run the test as detailed in the book but the fuel delivery system seems to be working.

I have a line on another 1991 Passat GL, 187K. I've started the car, it sounds like its running well (although so did mine when I bought it). I didn't take it for a drive, although he said it was drivable. The guy selling it (from his auto shop) tells me that the transmission does not shift into all gears. He says he couldn't figure out why. The ground under the car is saturated by ATF.

Otherwise, the car appears to be OK. There's a small rust spot on the body and a door is fairly badly rusted, but otherwise it seems fine. Did I mention that it starts (unlike mine...)?

The guy wants $900 for the car. I figure I can pull the transmissi>check for air leaks , do you hear the fuel pump make noises for a >second,when you

Reply to
Laurence MacKenzie

SNIP SNIP

So you want two that are not driveable? And what if you change over the trans and you still have two that are not driveable? Twice as much grief!

I vote you fix the one you have! Find a VW mechanic that can actually repair it. Ask others that own VWs where they take theirs.

You basically need three things:

  1. compression
  2. fuel (in proper amounts)
  3. spark (at the proper time)

Did you pull the spark plugs and "read" them? I have seen marginal ignition coils cause problems starting the engine too! I have seen a non-functioning cold start valve/injector cause the engine not to start!

good luck and let us know what you find!

later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Reply to
dave

Really stupid question, but is the cat plugged? Try dropping the damn thing and cranking it. I have a plugged cat and it did almost the same thing...

Good luck!

Reply to
ChaosReturned

I picked up the other one. I've had lots of problems with the first (red) one. It has over 280K km on it, while the new (silver) one just turned 200 (I mean just, I took a picture of the odometer when it rolled ... don't worry, I happened to be pulling in the driveway). The red one also had some body damage at the back end ... would have cost a fortune to fix.

All is going well with the new one. The transmission is still in limp-home mode. I tried swapping the Digimats and the speed sensors (on someone's suggestion). Neither fixed the problem. Wiring is secure. Gonna bring it to VW to get the fault codes (don't have a VAG-COM ... don't know anyone local who does - I'm St. Catharines, Ontario if anyone has one nearby).

Replaced the front pads and rotors. The parking brakes are FUBAR, but will be fixed shortly. Kinda weird, rear calipers work when actuated hydraulically (brake pedal) but not mechanically (parking brake). I ordered new calipers, but if anyone knows some trick to get the mechanical part working, I'd love to hear it. All I've done is replace the cables and work the lever on each of the calipers to loosen them up. The problem is on both sides.

Other than that, I can't find any problems with the new one. I didn't receive any kind of service history with this car, what kind of PM should I do before I start putting mileage on it?

Reply to
Laurence MacKenzie

look here

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later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Reply to
dave

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