Random engine stall

Car info: 1998 NB GL 5Sp TDI
Symptoms: Random engine stalling
Corrective measures:
1. Replace fuel filter
2. Replaced Relay 109 (with offical VW grey relay)
There are no DTC's and when the engine is running the car runs well with not performance issues.

The problem is a randon engine stall. Once the engine dies its a matter of letting the car sit for a few minutes and it can be restarted. The car can run for 2 or 3 consequtive days without a stalling episode then as if out of nowhere the engine will just stall.

Has anyone else seen this ?

TIA
Herm

When the car stalls, is there still electrical power? If the electrical power is maintained, as it is when a car stalls, perhaps an erratic fuel pump solenoid or the wire going to the solenoid is damaged?

Let me just say, Herm, I'm glad it's you dealing with this, and not me...

I don't know how you find the time and patience to deal with it. I'd hate to send them to a dealership. A car like that could sit around for weeks with no answer. I'm sure it'll be some loose ground or erratic solenoid or switch... mostly it sounds like a nightmare. Good luck.

Fred

I'm having the same thing on my 2004 Jetta TDI 5 speed, running B100. People are suggesting the lift pump in the fuel tank. But I don't know if you have one of those... still trying to sort it out. Have changed the fuel filter, and the problem persists in that annoying random sort of way...

no lift pump pre 04-ish

Herm TDI said:

Car info: 1998 NB GL 5Sp TDI
Symptoms: Random engine stalling
Corrective measures:
1. Replace fuel filter
2. Replaced Relay 109 (with offical VW grey relay)
There are no DTC's and when the engine is running the car runs well with not performance issues.

The problem is a randon engine stall. Once the engine dies its a matter of letting the car sit for a few minutes and it can be restarted. The car can run for 2 or 3 consequtive days without a stalling episode then as if out of nowhere the engine will just stall.

Has anyone else seen this ?

TIA
Herm

Click to expand...

Herm,

Have you checked the engine speed sensor G28?

It is a fairly common issue with the 2.0 gas engines. Once it heats up it becomes a open circuit and the engine stalls or will not start hot. I have seen this issue on TDI's as well. Although not nearly as common place.

The connector just in case you are not familiar with its location is on the front of the engine and it has 3 terminals. What you need to do is get the engine to where it will stall/not start and measure resistance between terminals 1 and 2. The specified restistance is 480 - 1000 ohms. The sensor it's self is located in the block in front of the starter.

I actually just replaced one this morning on a 2.0 gas for a similiar situation.

I have also found the if you are having trouble duplicating the failure to let the engine run with a heat gun pointed at the sensor. Be careful of the heat setting of the gun you do not want to melt it. My heat gun puts out 1000* F and it will easily melt anything plastic.

My bet is a bad G28

Hope this is it and what I wrote helps!

Jeff

Did you find the problem with this car?

I just recived the new G-28 (Eng speed sensor). I now have to schedule a date to do the install.

However I have some doubts if this is the cause. If this sensor were defective it would through a DTC such as G-28 open or short to ground?

Herm TDI said:

I just recived the new G-28 (Eng speed sensor). I now have to schedule a date to do the install.

However I have some doubts if this is the cause. If this sensor were defective it would through a DTC such as G-28 open or short to ground?

Click to expand...

How about a fuel line issue before it gets to the filter?Could the lines have crud in them and when it is just right it is enough to lose fuel pressure?

Herm TDI said:

I just recived the new G-28 (Eng speed sensor). I now have to schedule a date to do the install.

However I have some doubts if this is the cause. If this sensor were defective it would through a DTC such as G-28 open or short to ground?

Click to expand...

Most of the time no it does not. I could probably count on one hand the cars that did have a open or short DTC set when the G28 was failing. There appears to have been a change in the sensor sometime in the early 2001 model year. All of the G28's I have replaced have been on 1998 - 2000. Not counting mk3's. That would be all model years for them. The diesels do not seem to fail very often. I would imagine due the lack of waste heat energy.

Herm TDI said:

Car info: 1998 NB GL 5Sp TDI
Symptoms: Random engine stalling
Corrective measures:
1. Replace fuel filter
2. Replaced Relay 109 (with offical VW grey relay)
There are no DTC's and when the engine is running the car runs well with not performance issues.

The problem is a randon engine stall. Once the engine dies its a matter of letting the car sit for a few minutes and it can be restarted. The car can run for 2 or 3 consequtive days without a stalling episode then as if out of nowhere the engine will just stall.

Has anyone else seen this ?

TIA
Herm

Click to expand...

Sounds like something either electrical or fuel starvation.

Fuel starvation: I was thinking about the early A4s with rev B or rev C version fuel pickup senders with the troublesome check valve that likes to become the first victim of icing/gelling in the cold....but the 98 NB is older (A3?)....does it use the same fuel pickup sender with the pesky checkvalve that the early A4s had?

Electrical: Could the fuel cutoff solenoid in the IP be going intermittent electrically? After it's dead, and while it won't restart, is there 12V present at the fuel cutoff solenoid? It's possible for there to be 12V at the solenoid but the solenoid is electrically intermittent, causing it to be "off" sometimes when it should be "on".

Electrical: Intermittent connection somewhere inside the ECU? If while it's running, can you induce the failure by moving cabling around? I recall reading about a PD Jetta intermittently stalling out and the root cause was a intermittent connection inside the ECU. The problem was found when cabling to the ECU was wiggled slightly while the engine was running, causing it to die on command. A new ECU fixed it.

Good luck and hope you get it figured out.

Herm, the diesels once they are running, are more of a problem to stop, than to shut off. I have seen a lousy t fitting at the fuel filter give me headaches. And, without doing anything, they started again, with a fair bit of cranking, but nothing else. Just thinking out loud here.

I replaced a couple of orings in the t fitting that day, and all was well, but, the filter housing appeared oversized a little...aftermarket parts can be like that. good luck

Craig

defective G28

jharrison said:

Herm,

Have you checked the engine speed sensor G28?

It is a fairly common issue with the 2.0 gas engines. Once it heats up it becomes a open circuit and the engine stalls or will not start hot. I have seen this issue on TDI's as well. Although not nearly as common place.

The connector just in case you are not familiar with its location is on the front of the engine and it has 3 terminals. What you need to do is get the engine to where it will stall/not start and measure resistance between terminals 1 and 2. The specified restistance is 480 - 1000 ohms. The sensor it's self is located in the block in front of the starter.

I actually just replaced one this morning on a 2.0 gas for a similiar situation.

I have also found the if you are having trouble duplicating the failure to let the engine run with a heat gun pointed at the sensor. Be careful of the heat setting of the gun you do not want to melt it. My heat gun puts out 1000* F and it will easily melt anything plastic.

My bet is a bad G28

Hope this is it and what I wrote helps!

Jeff

Click to expand...

I replaced the G-28 (eng speed sensor) and no joy. The stalling problem persists.

I have made a few close observations.
1. The engine stalls only at slow speeds under light loads.
For example: slowing down to change streets for a rual back road onto a smaller road. Slowing down decelerating and going into second gear to compleat the transition from one road onto another but befor you step on the accelerator the engine will stall. Eng speed about 1,100 RPM and MPH about <20.

2. On a hilly section of road going down hill in 4th gear at 45 MPH the making the transition to an incline at the base of the next hill. MPH about 25-30: RPM @1,600 just as you are about to accelerate the engine will stall.

3. Driving at 45 MPH in 4th gear with the cruise control set the engine rarely stalls. RPM is steady near 2K The car will drive nicely with smooth power.

4. On the interstate I had only one engine stall above 65MPH in 5th gear

5. one other observation is it takes a bit more cranking to start the engine when it is at normal operating temp (190*F) Just a little more cranking time but nothing dramatic.

This engine stall is random and about the only consistant pattern is the low speed /low engine load. This stalling happens with the engine hot or cold.


I hope someone has something to offer.

Herm

have you check the ignition switch?

Just for fun, have you disconnected the anti-shudder valve? What about the fuel shutoff solenoid? Is it operating properly?

o-ring on the fuel cut-off solenoid tip dislodged?

check operation of the clutch pedal switch?

If neither of those, swap out the go pedal with one from a car without the problem and retest.

If you have a scope with glitch capture....it would be a bit easier. But.... I am sure you have seen the Phantom stall on B4 and Mk3 right? Often a bad fuel shutoff solenoid or a chafing IP wire usually near the starter or the coolant bypass pipe. This issue often sets NO CODES at all. I have found in 99.5's it is the same. I suppose the ecu's are not as sensitive as the 00 and up. I have had 5 phantom stalls in Mk4's and all have been 98-00....only one had a code.