misfire problem rough idle

flat6

Member
Joined
Aug 28, 2011
Location
ramona ca
TDI
2002 Jetta
2002 jetta alh engine with 208,000 miles. Car was going into limp mode, but wife is so soft on the car i have no idea how long it was doing it. Than it started misfiring and smoking. Smoke is white and smells like unburned fuel. I took the intake and the turbo off and cleaned everything. Replaced all the vacuum lines, egr and maf. The vacuum lines were worn , egr was damaged trying to get a hose loose, and maf was reading low acording to the vagcom tests. The only code the code I found in the log was an over boost. Since I put it back together I still have a mis fire the car runs poorly. If I pump the pedel can get some proformance out it, but the smoke is black when i do that. Need some help she loves this car and I need to get running right if i want any peace. There is some oil in the intake pipe, i can hear the turbo changing pitch so a think it is working. with no codes to point the way the injectors are the next thing to vist. I am in North San Diego if someone has a mechanic they trust let hear about them. The dealer has been a disapointment in the past so I am not going that route again.
 

Seatman

Top Post Dawg
Joined
Apr 23, 2010
Location
Scotland
TDI
2014 Skoda rapid elegance 1.6 cr tdi
Check the asv is fully open, just pop off the boost pipe where it goes onto the intake manifold and have a look, it should be wide open.:) (anti shudder valve)
 

energy

Well-known member
Joined
Mar 14, 2005
Location
Leavenworth, WA
TDI
mtdi caddy, tdi Multivan Syncro
with that many miles on the injectors I'd start there--get some aftermarket larger ones and you'll be pleasantly surprised!--both mileage and performance-wise!
 

mk3

Veteran Member
Joined
Sep 13, 2005
Location
Wisconsin, USA
TDI
03 Jetta GLS 5-speed
with that many miles on the injectors I'd start there--get some aftermarket larger ones
sorry, I don't mean disrespect but I think the OP would not want to get larger nozzles or aftermarket. If it turned out to not be the only problem it would greatly confuse the issue(s).

Have you checked the injector balance in vag-com? It uses crank acceleration from what I understand and sort of detects if one cylinder is relatively weaker or stronger than the others. That might help determine if you have a bad nozzle or nozzle body.
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Weedsport, New York
TDI
2002 Jetta GLS TDI 5M
I'm wondering if the car didn't have an "undesirable event".
Let's talk about service and specifically, the timing belt. Was any significant service performed within the last year or so? By any chance has the car ever had a timing belt break and it was replaced (maybe several thousand miles ago??)

When has the timing belt been changed? That car should have had at least two TB changes by now. I'm going to recommend:
Inspect the timing belt.
Inspect the cam and injection pump for proper mechanical timing.
Inspect the camshaft and followers for wear.
Do a compression check.

If that is more than you're comfortable doing yourself, use the list (I believe in the 101 forum) and see if you can find a TDI guru nearby.
 

flat6

Member
Joined
Aug 28, 2011
Location
ramona ca
TDI
2002 Jetta
Thanks for the reponses My wife drove to car off the the lot and a lot of other places, so we know all of it history. It is due for a timing belt but did not want add anything else to the mix. I will do the injector test when figure out how. Is there a thread somewhere that explains how to do this test? The mis fire started suddenly not slowly, which makes me think it was not a not a wear item. If I could find someone to take it to I would I work long hours and just don't have time, but the last last time I took it to the dealer I still had fix it myself after two vists. There does not seem to be a Guri in the area. I will follow up on these items and get back to you .Thanks for the help.
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Weedsport, New York
TDI
2002 Jetta GLS TDI 5M
:(

I'd recommend do not run the engine any more, and pull the timing belt cover off, check the timing belt for missing teeth etc.
Hope you don't need this info, but have a strange feeling you do.

If the car happens to be automatic trans, you might want to stop, obtain feedback before spending money on the engine.

High mileage timing belt kit A4 ALH (includes serpentine items) about $449
http://www.idparts.com/catalog/product_info.php?cPath=121&products_id=2298

Metalnerd timing belt tool set A4 ALH about $225
http://www.idparts.com/catalog/product_info.php?cPath=37_134&products_id=1262

VAG-COM computer interface (needed to verify / set timing after TB change)
Several choices ~ $250- $350
http://www.idparts.com/catalog/index.php?cPath=37_136

Forum user Franko6 for head rebuild

I am not affiliated with idparts.
There are other vendors on this forum who also have solid reputations for quality.
I have done business with idparts (previously tdiparts) for years and can recommend them.
 
Last edited:

heliguy

Active member
Joined
Jul 8, 2009
Location
Whitby, Ontario
TDI
2001 Jetta TDI
Had the simillar issue without the backfire on a 2001 TDI. It was hit or miss on the problem but would go into limp mode when it happened. Anyways I had a sticky wastegate actuator. So it wasn't allowing the turbo to dump pressure which set off the overboost protection code. Might be worth a look if you havent already. I know have rough idle again and smoke as well backfire. This time due to low compression on a cylinder. Broken ring or burnt valve, will find out today in the process of ripping it apart. Compression test might be something to consider.
 

flat6

Member
Joined
Aug 28, 2011
Location
ramona ca
TDI
2002 Jetta
The timing is on and the belt is in good condition. You right it is due. It never had a broken belt or many other issues. Where do get an adapter to do a compression test with? Thanks for the parts link it makes me feel better, because that where I have been buying my parts. The car is a 5 speed. I guess should have let everyone know I do have mechanical ablilty and tools. I just don't have time to play with any longer she is about to kill me. She does not like driving the farms f150 around. I will run an injector test tonight and see where that takes me. I think I made a mistake put the the old turbo back in. I don thinks it the current problem but it is leaking more oil than I tought it was.
 

The J

Veteran Member
Joined
Oct 14, 2010
Location
Long Island, NY
TDI
'03 Jetta Wagon
your best bet is to get a vag-com cable for diagnosing.

the injector balance is a field you can monitor with vag-com.

a diesel needs a different compression tester than standard gassers. the cylinder pressures are much higher so a standard compression gauge will not work.

i got mine at harbor freight and for $40, it does all i need it to do. the kit comes with the M6 threaded adapter you need. look for numbers in the 450-500 psi range on a warm motor.
 

flat6

Member
Joined
Aug 28, 2011
Location
ramona ca
TDI
2002 Jetta
I have a vagcom set up sorry to say i am not the best at using it the car has totaly trouble free up to this point. Just been using it to adjust the timing. Thanks for the tip about a tester from harbor freight, I' ll pick one up today.
 

The J

Veteran Member
Joined
Oct 14, 2010
Location
Long Island, NY
TDI
'03 Jetta Wagon
just make sure when you use that compression gauge that you relieve the pressure completely before trying to remove the gauge from the fitting. if it feels like the gauge is stuck, you still have too much pressure in the gauge. pulling it out under pressure can cause it to pop out abruptly and could injure you or the gauge, or both.
 
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