Help my tdi is stalling

[cage]

I have a 98 Beetle tdi and yeaterday I stopped at a light and the engine just quit. I thought I must have done something stupid since it started right up. a few hours later I drove 40 miles pulled into a parking lot pushed in the clutch and it quit again. After work yesterday I was driving down a 35 mph. street and when i would take my foot off the gas to coast the engine would shut down but the car would push it along then when I pressed on the gas it would start running again. I did this three times in a row then the car infront of me stopped to make a turn and I knew that if I pushed the clutch in it would quit and sure enough it did. today it has been ok so far but now I don't trust it. It starts up fine after the stall and it runs perfetcly otherwise. What is happening? I can understand it quitting but why does it restart just by pushing the gas when still rolling? If there is a fuel pump problem it should not turn back on by pushing the gas.
why is the fuel pump turning off when the gas is released? Is the computer mistaking releasing the gas as turning the car off? It is too wierd. Plus it seems as though if it stalls it will then restart and not repeat the problem during the remaining trip 'til it is turned off for awhile. Plus there isn't a check engine light warning. HELP!!!!

 

[mickey]

That sounds very much like an electronic problem. The TDI computer shuts off the fuel injectors when you're coasting as a fuel savings method. You may have noticed that when you're crawling along in 1st at a few mph, the "clattering" goes away if you lift off the pedal, and starts back up again if you press the pedal or the engine slows down to idle speed. It may be that the computer is not sending the correct signal to the injectors. Some possible reasons:

1. Whatever sensor detects engine speed is failing to recognize that the engine has slowed down to idle speed. The ECU is not getting the correct data.

2. The ECU is getting the correct data, but failing to respond properly. (Time for a new computer.)

3. The injectors are failing to respond to the computer. (Very unlikely! There are 4 seperate injectors. They can't all be faulty!)

4. You have a loose connector somewhere, or the insulation has been compromised and a wire has shorted. (The simplest explanation, and the most probable, IMHO.)

I've found that when weird stuff like that happens, you can fix it yourself as often as not just by wiggling various electrical connectors. A wire somewhere might not be making proper contact. Look around your pump and injectors for various plug-in wire connectors. Disconnect them (with the key off, of course) and then reconnect them. Make sure no wires have been rubbing and the insulation abraded. Also, use your ears! Start the engine, then try to duplicate the problem with the hood open and the heat shield removed from the top of the motor. If you rev the engine up, then let it coast down you'll notice the "diesel clattering" will go away. It should resume when the engine reaches idle speed. If it doesn't, and the engine kills, then my guess is correct.

-mickey

 

[cage]

Mickey, today it has run flawlessly. I drove my usual route home from work I even duplicated my quick getaway that I had to do yesterday due to traffic and I can't get it to do anything. I did look under the hood and pulled on wires (not hard) and everyting looks good. The thing is that it seems like a computer problem 'cause it wasn't an intermittent thing that one would get from a bad connection or anything. Once it decided to act up it kept acting up until it had a chance to stall then it reset itself and was fine. I think it had a brain fart 'cause if it were a sensor or servo it wouldn't necessarily reset when you re-start the car also a sensor would bring our all too eager check engine light a glow. I know people say computers don't f--- up but I know that they most certainly do so I guess I will dismiss it as that. Hopefully it wont return.

 

[D.Johnson]

Cage:

After having my TDI in the shop 3 times, for a total of 19 days and 1,100 miles put onto the clock by the maint. dept, they finally agreed to swap out the ECU chip.

My engine was also cutting off. Without warning, going uphill, going downhill, going straight, going 10mph, going 55mph, in 1st gear, in 5th gear, between gears, while hot, while cold, after a 500 mile drive, leaving the driveway....it didnt matter. The engine would just shut itself off whenever if felt like it. The service department replaced probably everthing they could, and nothing would work. They finally swapped out the ECU, and the problem has not returned in the 3 days I've had the car back.

Another VW dealer I know of has also had to replace an ECU chip. That was for a Passat that was also cutting out, and they found that ECU chip to have cracks in it.

If you take it to the dealer, and they state that no fault codes are stored, then I would guess that the chip itself is kaputt.

Good luck, derrik

 

[Craig]

This is scary stuff. It is one thing when the car is under warranty and yet another if phantom ECU problems occur after the warranty has expired. VERY EXPENSIVE.

This is the one area where installing the Wett chip has me apprehensive. If I understand the process, it sounds like they unsolder the original, install a socket and then insert the Wett chip. Potential problems could occur down the road. What happens if there is a bad solder joint on the socket? It may occur immediately or not for years!

Also if there is a problem with the ECU and the dealer finds it has been modified, I can just see the response: "It's your fault since you had it altered."

Maybe I am just too paranoid, but decades of working in the electronic field has taught me Murphy's Law: "If anything can go wrong, IT WILL!"

 

[SkyPup]

True, we will have to see what happens over time, however I don't think that the Wetterauer hardware would be any more prone to failure than the standard Bosch Siemans stuff, after all it is all made by Inte, TI, Motorola, Siemans, NEC, etc. Hardware is hardware, but you are correct that the inexperienced can be taken a county mile by those with the knowledge. BTW, it seems that most VW service personnel also have a hard time with the electronics themselves.

 

[JRZTDI]

Don't know if this helps at all but, here's the info I can give. On May, 17, 1999 I took delivery of a shiney new '99 Jetta GLS TDI with a luxury package. We love the car so far, however, the day we picked it up, it all started. There were certain, light throttle/low RPM situations where the power would completely fall off, usually in the 1200-1500 RPM, 30 MPH and under area. It was almost as if someone had an on/off switch for the turbo charger and turned it off at certain times. Very scary to say the least. Anyway, I called the dealer they had me bring the car down, it happened to them as well, they cleared the faults in the system and everything SEEMED ok. Low and behold, it was still there. We called them back and made an appointement to drop it off the following Monday. At 1 week and 1,000 miles old it went in for diagnosis, they traced the problem back to a bad ECU. The ECU was replaced and the problem hasn't come back yet. I put over 100 miles on the car in the last 2 days in many different scenarios and the problem has yet to resurface. At this point I feel confident the problem has been resolved.

 

[cage]

I wonder if that is my problem. The crazy thing is that it hasn't done it now for two days + it has never cut out while driving just releasing the gas and pushing in the clutch. Do you still think it is the ECU?

 

[Andrei Rinea]

Although these are probably expired / solved issues I must add that it's probably a relay or a contact that's acting up not the whole ECU or sh*t like that.

I had (and I'm having again) some funny times with my stock alarm system that gets bored from time to time of working and lets its relays loose and starves the poor ECU of electrical power. Ofcourse this means engine stall and sometimes I have to wait for the relay to cool down before it works again.

I replaced one of the two relays but after just 1 1/2 years the second ECU relay in the stock alarm is giving up too. A new alarm module is just 200$ so I said efff you stealers. No money from me.. At least as long as I can use a soldering gun

 

[hpc]

Had same problem on my '02 NB-TDI. Would be driving along and
it's like someone turned the key off except all of the electricals remained
running like nothing had happened. TDIRacing replaced the
J9 (I think this is the relay) relay and been running fine since.

Good luck.

Lon

 

[hpc]

OOPS! So much for memory. How 'bout 109 relay.

Sorry.

 

[First_VW_TDI]

Hi,

I have a TDI from 1996, with 448000 km in the meantime. I also have once in a while the same error. I am very curious if you have solved the issue. Please let us know. I will give you some head aches I am having right now.

Issues I have related to not starting, starting and dying immediately, or starting and stopping for a brake and then not re-starting, or dying when driving.......Here are the effects I am having:

• Turn the key, all LED's, lights etc. function ok, turn key to start, starts, runs, and immediately shuts off. When it happens, Usually several times after eachother.
• Turn the key, all LED's, lights etc. function ok, turn key to start, nothing happens. Only some relay click, but no turn whatsoever. Here also, when it happens, several times after eachother.
• After a long drive, engine hot, outside tempetature warm (>25 Deg C), switching the engine off. Then restarting won't work. Same effect as the second description. When you wait for eg 20 minutes, and have the car cooled down, starts without a problem.
• Recently (Sunday May 20th), when driving 100km/h, i switched on the lights. When doing that the glow plug indicator flashed instantly. Also the brake fluid indicator flashed seconds later also. After a 100meters or so all my clocks in the dashboard went dead to zero, engine went dead and i had to pull over (was quite a dangerous excersize). I turned off all the loads, and tried to restart, which worked.....? I removed relay 109 and ticked a couple of times on it and put it back. I arrived home safely........No errors since.

What i did to solve (hopefully) these issues:

• I have replaced the contact switch (August 2006)
• I have replced relay 109 (after sundey May 20th 2007)

I hope with the latter, I have solved the issues.......

If you have advice, please let me know. An email is always OK.
__________________
________________
Regards, Pierre
Passat Variant TDI, 1996, 448000km