Need some SERIOUS expert help

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
Greetings, all. Hope all is well. 98 Jetta AHU 255k. Mechanic has had car for too long and can't get it to run. Started with the P1550 code (which was cleared). Found a few wiring issues, fixed. However car will crank but not start. When in pre ignition no lights come on in the panel but the damned clock. Wiring is good according to him. But seems to be stumped on why it wont start. New FSU in the tank. Giles pump with under 5k with rebuilt injectors by him as well. Guys been apologetic because its my beater back and forth to NYC. ANYTHING u may know and can share would be greatly appreciated. Thank you in advance.
 

hskrdu

Top Post Dawg
Joined
Oct 17, 2003
Location
Maryland and New England
TDI
2003 Golf GLS 4D 5M, 2015 GSW SE 6M
How good is your mechanic with TDIs?

Mike Hevner is just outside Port Jervis.


 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
He was recommended by a Mk4 guy. But hes stumped on this. So anything he can look for would be appreciated. If the suggestions dont work, ill have to haul it to mike. TY
 

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Southern California
TDI
1997 Jetta TDI (1Z)
These cars are notorious for issues with the ignition switch. If there is variation in what lights come on in the dash when you turn the key to "on" you might have a bad one.
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
These cars are notorious for issues with the ignition switch. If there is variation in what lights come on in the dash when you turn the key to "on" you might have a bad one.
Interesting, TY. But if the switch was bad, as you say, it would still crank with no results?
 

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Southern California
TDI
1997 Jetta TDI (1Z)
Possibly. If there are no dash lights, that may indicate either that the main power relay 109 maybe bad or the ignition switch. Since it’s much easier and cheaper to replace that relay, I would try that first.
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
Possibly. If there are no dash lights, that may indicate either that the main power relay 109 maybe bad or the ignition switch. Since it’s much easier and cheaper to replace that relay, I would try that first.
IIRC they may have replaced the 109. i will have to call the, tomorrow and verify. Again, TYVM
 

hskrdu

Top Post Dawg
Joined
Oct 17, 2003
Location
Maryland and New England
TDI
2003 Golf GLS 4D 5M, 2015 GSW SE 6M
If you wamt to troubleshoot yourself, we have a whole thread on NSCs (no start conditions):
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
If you wamt to troubleshoot yourself, we have a whole thread on NSCs (no start conditions):
TYVM, but ill admit with the advance in social media, i forgot about this site. I will check it out. Again thank you.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
These cars are so simple with regards to engine management, and need so little to actually run (especially a '98).

Here is what I would do:

Connect a scan tool, access the Engine controller (with the key on, you should be able to communicate with it.... if not... you have a problem)

Assuming you can connect, go to the engine data, and find a block that shows engine RPM.... then watch that while you crank the engine. If the value goes up, and shows cranking RPM (whatever that may be... 200-400 ?), then at least you know these two important things: the ECU is "alive" while cranking, and it "sees" the engine cranking. This is a VERY simple step to take.

If the ECU is not staying live during any of this, then you need to find out why. If it does stay live, but you see no cranking RPM, you need to find out why.

Pretty much everything else is simple mechanical old fashioned VE pump diesel. A stop solenoid on the pump. ON = engine runs, OFF = engine not run.

Ignition switches were common failure items on these cars, and often the ignition switch would lose the "run" contacts while in the "crank" position. So if you have the ECU working, the data up, and when you go to crank the car the scan tool suddenly loses communication with the ECU, then that is a good sign the ignition switch is bad.

Warning: tearing the steering column apart to replace the ignition switch is not a big deal, BUT, unlike most cars (including all newer VAG products), the A3's clock spring for the airbag is not attached to the column switches... it is attached to the bottom of the steering wheel..... you need to unplug the clockspring connector BEFORE you remove the steering wheel, or you'll break the clockspring to pieces and you'll have an extra expense to deal with.
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
These cars are so simple with regards to engine management, and need so little to actually run (especially a '98).

Here is what I would do:

Connect a scan tool, access the Engine controller (with the key on, you should be able to communicate with it.... if not... you have a problem)

Assuming you can connect, go to the engine data, and find a block that shows engine RPM.... then watch that while you crank the engine. If the value goes up, and shows cranking RPM (whatever that may be... 200-400 ?), then at least you know these two important things: the ECU is "alive" while cranking, and it "sees" the engine cranking. This is a VERY simple step to take.

If the ECU is not staying live during any of this, then you need to find out why. If it does stay live, but you see no cranking RPM, you need to find out why.

Pretty much everything else is simple mechanical old fashioned VE pump diesel. A stop solenoid on the pump. ON = engine runs, OFF = engine not run.

Ignition switches were common failure items on these cars, and often the ignition switch would lose the "run" contacts while in the "crank" position. So if you have the ECU working, the data up, and when you go to crank the car the scan tool suddenly loses communication with the ECU, then that is a good sign the ignition switch is bad.

Warning: tearing the steering column apart to replace the ignition switch is not a big deal, BUT, unlike most cars (including all newer VAG products), the A3's clock spring for the airbag is not attached to the column switches... it is attached to the bottom of the steering wheel..... you need to unplug the clockspring connector BEFORE you remove the steering wheel, or you'll break the clockspring to pieces and you'll have an extra expense to deal with.
Oilhammer, you are the man, THANK YOU. I will copy this and send it their way. And many thanks to everyone else (hkskerdu. garciapiano). I will also copy the troubleshooting page hskrdu mentioned as well. One question, tho. If no communication with scan tool, WHAT would that problem possibly be? TY Hopefully I can get this back to my commuter car. Hate using the 2015 Passat and my 07 Dodge Cummins (fuels killing me). Again, thank you to all and any more info/suggestions ARE appreciated. Stay safe, stay well.
 
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Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
The
Greetings, all. Hope all is well. 98 Jetta AHU 255k. Mechanic has had car for too long and can't get it to run. Started with the P1550 code (which was cleared). Found a few wiring issues, fixed. However car will crank but not start. When in pre ignition no lights come on in the panel but the damned clock. Wiring is good according to him. But seems to be stumped on why it wont start. New FSU in the tank. Giles pump with under 5k with rebuilt injectors by him as well. Guys been apologetic because its my beater back and forth to NYC. ANYTHING u may know and can share would be greatly appreciated. Thank you in advance.
98 AHU jetta has no lift pump.
So whatever was put in there is an upgrade when you go massive Injection.
Check ground connection at the round harness at the head. It must be bolted down.
Relay 195 is also suspect
Ignition switch and IP harness. Check and make sure that it's good
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
The

98 AHU jetta has no lift pump.
So whatever was put in there is an upgrade when you go massive Injection.
Check ground connection at the round harness at the head. It must be bolted down.
Relay 195 is also suspect
Ignition switch and IP harness. Check and make sure that it's good
Was aware of no lift pump, TY. But I will forward your ideas as well. Its my little rustbucket but runs (or ran...lol) like a top. Thanks much. Stay safe, stay well, Jimmy
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
Wouldn't hurt to pop open the ECU and make sure both chips are still fully seated.
If the above suggestions do not work, I will send them this as well. Hell, maybe ill just send it. Thanks much Was gong to send the ECU to Malone over the summer while on vacation, they screwed that up....
 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
Morning, experts. Update and they are still stumped. Car in pre ignition now resets the clock every time. GP light does not light up and told no power to the GP's. Runs with a quick shot of ether. Thats about it. Fire away and again, many thanks.
 

Phi1osopher

Veteran Member
Joined
Jul 31, 2019
Location
Austin, TX
TDI
'96 B4V TDI Passat Wagon
I am sorry you are struggling; I wish I had something to offer....
Since you said you need serious help, I guess you don't want this guy getting involved:


 

smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
Have you checked to make sure that the ignition switch is working properly?
ignition switch was installed. Guess they will have to check that. Just frustrated they've had the car over 4 months. and they cant get it to run. Aside from being my beater, we all know fuels creeping up. Even more frustrating was i had to come here to get answers. Every other mechanic I know will google it, you tube it, or go to pages like this. Yet I had to do it. Think it may be time to go somewhere else. EVERY suggestion posted here has been copied and emailed to this shop. And yet they came highly recommended by a Mk4 guy. SMH.
 
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smketrny

Veteran Member
Joined
Jan 4, 2009
Location
Orange County, New York
TDI
1998 Jetta TDi, 2015 Passat TDi
I am sorry you are struggling; I wish I had something to offer....
Since you said you need serious help, I guess you don't want this guy getting involved:





Hell, he may do a better job LOL. THANKS TO ALL FOR THE REPLIES, IDEAS AND SUGGESTIONS. SERIOUSLY, CANT THANK YOU ALL ENOUGH. If ya's only lived closer lolol
 
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