Golf III 1.8 GL: Engine fall into a coma

Hi!
I have a Golf III 1.8 GL with ABS engine. For two months now I have had big problems with my engine and the car has been in and out of
Volkswagen auto repair ten times without finding the problem. This has become very irritating and I have now decided to do the work myself.
The problem is that sometimes when I start the engine it falls into a coma for about 15 minutes. The engine idles around 400 rpm and it will not respond to the throttle at all. After a while it starts to responds and I can start driving my car. When I have driven the car some miles a ticking noise from the vents occur.
The auto repair has changed the timing belt, the lambda sond, the distributor, the ground cable to the engine and the rotor without even having noticeable effect. Also they have changed the ignition timing of the engine several times.
I suspect the problem is the hall-sensor. The auto-repair says the hall sensor either works or does not work at all so they think it is not the hall sensor. For a while I also suspected the coil but I can not see how the coil can interference with the timing of the engine.
The problems occur particularly after a cold night and when the weather is wet.
Please help!
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In rec.autos.makers.vw.watercooled, sungam wrote:

The hall sensor would tell the engine control unit when to fire in the cycle. If that were intermittent, you would get irregular and rough running at best, and not just a slow idle.
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Would be great to know what year you got. From 1985 to 1992 VW used 2 different FI system and each had minor differences within each!

http://www.autoforumz.com/Volkswagen-Golf-III-GL-Engine-fall-coma-ftopict113283.html
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He said it was a Golf III 1.8 GL with an ABS engine so it can't be '85-92. It's probably the 1.8 that non-US A3s got.
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"noway9" wrote:
> > > Would be great to know what year you got. From 1985 to 1992 > VW used 2 > > different FI system and each had minor differences within > each! > > He said it was a Golf III 1.8 GL with an ABS engine so it > can't be '85-92. > It's probably the 1.8 that non-US A3s got.
It is a 1993 modell bought from Germany. I live in Norway :)
It seems to me that the engine has a serious ignition timing problem. Sometimes when I start the engine it will hardly run - it just idles at low rpm (500 or so). Then after 10 to 20 minutes it starts to reponds on the trottle. After two or three minutes more with some backfires now and then I can start driving the car but the engine performance is weak. The engine becomes stronger and stronger while I am driving and in a short period the engine is behaving "normal". Then after 5 to 10 minutes ticking noise from the valves occur and stay there for the rest of the trip.
The sympthomes I guess can be caracterized as "changing/unrealible igniting timing". In paricular the problem occur if the weather is cold, wet and/or misty.
I suspect the problem could be the hall sensor, but I do not know for sure. Could it be a bad knock sensor or wear of the axel to the rotor shaft?
Please help.
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If worse when damp, I suspect ignition. New plug wires and new distributor cap and rotor should do it but specifically go out to the car at night with a spray bottle and in the dark mist over the engine's plug wires and distributor and if you see arcing, that's the problem part. Are any of those parts fairly old?

I would think a flaky Hall sender would be more likely to cause the engine to stall completely and then maybe later start up again but I wouldn't expect that to just cause general rough running.
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i don't know much, but when my coil went out on my 85 gti...it died all together....If you had a faulty coil..i would assume it would be the same..or make the engine skip. but i don't think that would be your problem as you said you have a smooth idle problem, (again i'm no car expert) have you check the vacume hoses and all related componets?
Another thing i know from personal experience...when i replaced the lifters on my 85 gti, i goofed the timeing up, and basicly did the exact same thing as you described in no responce to the pedal. Maybe that would shed some light? I know you said the garage replaced your belt, distributor and such. Maybe you should go back to basics, make sure everything is tdc and go from there.
As your sensors, could be a sensor too. My 95 jetta had a problem, and i could never ever find out what caused it. It would just lose power when it warmed up for no reason. I redid the head, and valve steam seals..never corrected the problem.....unfortunatly I didnt have the money to take it somewhere to diagnose the problem. 200 dollars for 1 sensor was not something i wanted to do a trial and error on. Hopefully this help in some fasion with my experiences.
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What do your spark plugs and wires look like? The ticking noise could be related but first see what kind of condition the spark plugs are in. When was the last time you change plugs and wires?

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Where in the world are you? It looks like you have a Digifant III engine, like what we got down here...
Most advice you will get in this forum will not apply directly to your engine, as it did not sell in the US or Canada.
In that engine, I would replace the coolant sensor first. Its cheap and easy to change. If that does not fix it, there are three known failure spots on that inyection system:
-The Coil selfdestructs around 60.000 miles or 8 years. Always. All cars down here had the coil replaced if older than 1998. I would also replace the rotor and distributor cap, as they are most likely original and worn out by now.
-There is a relay in the fuse box labeled '30'. Its the relay that gives power to the ECU, the inyectors and sensors. They fail due to vibration and get high resistance. First you get erratic idle. Then hesitation. Never completly dies, making it hard to diagnose. If yours is BLACK, replace it with one that is WHITE. Its a re-engineered version and lasts much longer. Down here they cost around US$30.
-The idle stabilization box (round metal thing besides the throttle body) get oily and sticks. Take it out and clean is with carb cleaner.
Hope this helps. I HATE that inyection system. There is very little documentation avaliable and it gives horrble throttle response.
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Ok, if you want to look at the problem yourself, I can try to explain it works :) Your car is equipped with Monomotronic fuel injection system, which is somewhat funny: a very primitive hardware and a very smart ECU. Yankees call it "throttle body injection" :)
First, what tells the ECU itself? Any errors?
Second, I would look at the obvious - air leaks. Your symptoms do not suggest it, but anyway... There are only two places where it could happen: the rubber "basement" of the injector unit (it cracks sometimes). Just swing the injection unit with your hand and look. The second place to look is two thin plastic tubes (the ends of them), which are comming from the back of the injection unit and going to the coal container which is located under the air filter box.
The next (most probable) thing is the sensors and wiring. There are not much of them, and the most are monitored by the ECU. 1. Coolant temperature sensors, located on the upper coolant eee... "tube" :) If you disconnect the plug, ECU will think "it's cold" and rpm's will rise to ~1100. Just try it when your car starts to behave funny. If nothing is happening, then the cause is probably somewhere else.
2. The injector, or more likely the plug and wires. If tou look at the injection unit, then there are three plugs on it: if you stand in front of the car, then left (or passenger side) the is a stepper motor (idle stabiliser) with a plug on it, then in the middle is a brown plug for injector and air temperature sensor, and finally right (driver side) - a trottle body potentiometer with a plug on it. It happends sometimes (I had this problem last week), that the wire just breaks off inside the plug, but stays semi "connected" most of the time. So, just "wiggle" the connector with your fingers sideways, try to pull the wires etc while the engine is running. If your engine dies, then you found it. My car also started to behave funny, idling at ~500rpm, jumping rpm's, "jerking" and so on. But only sometimes, once every two of three days. No ECU errors, nothing. The problem was a broken wire in the injector plug.
3. Throttle body potentiometer, the most expensive part after the ECU (400 euros or so :( It it basically the only information source, from which ECU knows how wide the throttle is open. Check the plug and wires.
4. Coal container. Unlikely causing a trouble, but you can temporarily "disconnect" it by taking those two thin plastic tubes off, and then somehow "hermetising" the holes.
5. Lambda. No problem there as it was changed.
6. Stepper motor used for idle stabilization. I can't imagine it causing such problems.
That's all, as I said, the Monomotronic is a very primitive thing.

Hmm... doesn't look like they know what they are doing :)
I would say - check your wires and plugs. Wiggle what you can, pull what you can and so on.
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"draugaz" wrote:
> > > > The problem is that sometimes when I start the engine it > falls into a > > coma for about 15 minutes. The engine idles around 400 rpm > and it will > > not respond to the throttle at all. After a while it starts > to > > responds and I can start driving my car. When I have driven > the car > > some miles a ticking noise from the vents occur. > > Ok, if you want to look at the problem yourself, I can try to > explain > it works :) Your car is equipped with Monomotronic fuel > injection > system, which is somewhat funny: a very primitive hardware and > a very > smart ECU. Yankees call it "throttle body injection" :) > > First, what tells the ECU itself? Any errors? > > Second, I would look at the obvious - air leaks. Your symptoms > do not > suggest it, but anyway... There are only two places where it > could > happen: the rubber "basement" of the injector unit (it cracks > sometimes). Just swing the injection unit with your hand and > look. > The second place to look is two thin plastic tubes (the ends > of them), > which are comming from the back of the injection unit and > going to the > coal container which is located under the air filter box. > > The next (most probable) thing is the sensors and wiring. > There are > not much of them, and the most are monitored by the ECU. > 1. Coolant temperature sensors, located on the upper coolant > eee... > "tube" :) If you disconnect the plug, ECU will think "it's > cold" and > rpm's will rise to ~1100. Just try it when your car starts to > behave > funny. If nothing is happening, then the cause is probably > somewhere > else. > > 2. The injector, or more likely the plug and wires. If tou > look at the > injection unit, then there are three plugs on it: if you stand > in > front of the car, then left (or passenger side) the is a > stepper motor > (idle stabiliser) with a plug on it, then in the middle is a > brown > plug for injector and air temperature sensor, and finally > right > (driver side) - a trottle body potentiometer with a plug on > it. > It happends sometimes (I had this problem last week), that the > wire > just breaks off inside the plug, but stays semi "connected" > most of > the time. So, just "wiggle" the connector with your fingers > sideways, > try to pull the wires etc while the engine is running. If your > engine > dies, then you found it. > My car also started to behave funny, idling at ~500rpm, > jumping rpm's, > "jerking" and so on. But only sometimes, once every two of > three days. > No ECU errors, nothing. The problem was a broken wire in the > injector > plug. > > 3. Throttle body potentiometer, the most expensive part after > the ECU > (400 euros or so :( > It it basically the only information source, from which ECU > knows how > wide the throttle is open. Check the plug and wires. > > 4. Coal container. Unlikely causing a trouble, but you can > temporarily > "disconnect" it by taking those two thin plastic tubes off, > and then > somehow "hermetising" the holes. > > 5. Lambda. No problem there as it was changed. > > 6. Stepper motor used for idle stabilization. I can't imagine > it > causing such problems. > > That's all, as I said, the Monomotronic is a very primitive > thing. > > > The auto repair has changed the timing belt, the lambda > sond, the > > distributor, the ground cable to the engine and the rotor > without even > > having noticeable effect. Also they have changed the > ignition timing > > of the engine several times. > > Hmm... doesn't look like they know what they are doing :) > > I would say - check your wires and plugs. Wiggle what you can, > pull > what you can and so on.
Now I have changed the coil and the cable from the coil to the distributor. Still the engine behave strange. I have also tried all the suggestions in the previous postings without finding the problem. Another strange thing I observed is that the engine lacks power at high rpm and around 5000 rpm the engine "shuts down" until it falls below "4000" rpm.
The temperature sensor has been changed by the auto repair and I have also changed the fuel filter just in case.
Thank you for all your suggestions so far, but I still need more help if anyone can help me.
I will have a look at the hall sensor this weekend.
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fuel pump relay maybe? I dunno. I will assume your fuel filter is good and the catalytic converter or exhaust is not clogged. I have a collasping rear muffler on my 91 Passat that really killed the power sometimes.
good luck with it! BTW I always vote for testing components before replacing them. ;-)
later, dave (One out of many daves)
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