weird fuel starvation problem - 1989 Jetta

Hey Guru's

I have a 1989 Jetta and I've been having a strange problem.

I start the car, it idles fine, although smells a little rich, and drives fine for a few miles. Then, it will slowly decrease RPMs and I'll lose speed. Depressing the accelerator does no good. Sometimes makes it worse. If I do nothing but let my foot off the gas, it will slowly die. If I depress the clutch and let it idle, it will slowly die. Sometimes it will actually come back to life, but that's rare.

Now, If I turn the ignition off and back on while its sputtering and dying, it acts acts fine. It will drive for another mile or so before it repeats this problem.

I have had 2 mechanics here in Memphis look at it. One mechanic replaced both fuel pumps and the fuel filter and removed/cleaned/reinstalled the gas tank. This helped for a day. The other mechanic replaced a 'control module' located under the hood right in front of the winshield on the driver's side. This worked for about a week.

I've filled the tank with new gas (it was on 1/4 tank) and still have the problem. I have NOT used any store-bought additives.

I've also replaced the spark plugs/wires/distributor cap/rotor.

All replacement parts were purchased NEW from German-parts distributors and all are German.

I am at a loss here. Its a great car and I just want it to run right.

Any thoughts on what else I should look at ?

-Chris E.

Reply to
Chris Etzel
Loading thread data ...

Look at the coil area in the dark. If the weather is foggy, or you generate your own mist with a fine sprayer, all the better.

If you see arcing, that could account for unburned fuel.

Reply to
Tom's VR6

Well. I had a very similar problem and it was the 02 sensor.

Reply to
Dave

Are you going to fix it yourself? If so get a Bentley repair manual and a Digital Volt Ohm Meter. I think you could do a better job at fixing it than guessing. ;-)

I will assume that a "tune-up" has been done correctly esp. the ign. timing. That the engine is an 8V, and everything is in good shape. And BTW I only recommend BOSCH distributor rotors!!! I have seen too many cheap ones stump a mechanic. lol

Guessing at the problem....it could be: Bad wiring or usually broken ground wires at the engine intake manifold or cyl head coolant pipe. Fuel Pressure Regulator Oxygen Sensor or wiring Air Flow Box Coolant Temperature Sensor (for the Fuel Injection) Possibly even bad injectors Weak Ign. Coil or ???

Someone had a good site for diagnosing but I don't recall it offhand. Hey Guru's

Reply to
One out of many Daves

Try removing the gas cap, then driving, and see if that changes anything.

Reply to
gary556

I'm not a guru, but if your car is a plain 1.8 liter 8 valve gas engine with Digifant II ignition (not a Jetta GLI, or diesel), I have a suggestion

- Open the air filter housing and take out the air filter

- Does the air filter smell strongly like gas? Is it falling apart in your hands

- If so, your fuel pressure regulator may be the problem

A fuel pressure regulator sells for about $70 (aftermarket) and is fairly simple to replace. If you have a mechanic with Digifant ignition experience, it should take them no more than 20 minutes to install. If you want to do it yourself, I suggest you get a hold of a Bentley service manual for your car. The fuel pressure regulator replacement procedure is described on chapter 5, page 83

If the source of your problem was the fuel pressure regulator, you will notice the difference right away. Your car will sound better and run stronger than it has in a long time

It also would not hurt to ask your mechanic to take a can of Gumout and clean the throttle valve intake, idle air stabilizer valve, and emission control valve

Good luck

-- datatechnic

-----------------------------------------------------------------------

View this thread:

formatting link
Send from
formatting link

Reply to
datatechnic

Digifant II ignition (not a Jetta GLI, or diesel), I have a suggestion:

simple to replace. If you have a mechanic with Digifant ignition experience, it should take them no more than 20 minutes to install. If you want to do it yourself, I suggest you get a hold of a Bentley service manual for your car. The fuel pressure regulator replacement procedure is described on chapter 5, page 83.

the difference right away. Your car will sound better and run stronger than it has in a long time.

the throttle valve intake, idle air stabilizer valve, and emission control valve.

Reply to
wolfsburgnut

Gotta ask. Was the original bolt that holds the fuel line entry at the engine intake ever replaced? It has a tiny screen as part of the bolt. The replacement should NOT have the screen in it. Its a gotcha with rust problems in the fuel system delivery.

Reply to
Jonny

Perhaps your ignition coil is on its way out.

Reply to
Papa

I removed the Gas Cap (It didn't cost me anything to try it) today and it seemed to run a little better. No stalling on the way home.

I am going to drive it a little more and see if that helps. A 15 minute ride from downtown to midtown isn't a good indicator.

I also found the hose from the Air-Idle stablizer is collapsing pretty easily. I'll be replacing that too since squeezing it even a little bit causes the car to choke and stall.

Ordering a Bentley manual tomorrow.

Also, I've had two posts suggesting ignition coil, which will be next to test. If they're not too terribly expensive I'll probably just replace it anyway.

Thanks so much for the helpful suggestions. I'll let you know what I find out.

-Chris

Reply to
Chris Etzel

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.