poor idle and more...

[Michael Fowler]

Friend with a VW TDI 120,000 miles.
Has run flawlessly until now; oil and filter changes only.
Now it has a rough idle and some more roughness at about 2200 rpm.
My first thought is injector problems, but all my diesel experience is Mercedes and Ford IDI.
Is there a know problem that comes on at about this mileage (120,000) with these engines? How about cam problems, any history there?

He has put a can or two of Injector cleaner thru it with no improvement.

Should he pull the valve cover and check valve lift? How tough is that?

Thanks for your help.

 

[02AutoWag]

When was the timing belt done?
Has he logged onto www.tdiclub.com ?

 

[Michael Fowler]

Thanks for the reply.
I remember him talking about the timing belt in the Spring of 2008. he was going to do it himself, but, after reading the procedure, he opted to have it done "professionally".
I don't know the mileage, but it has been recently +/- done.

 

[02AutoWag]

Botched timing belt jobs by "professionals" are known for transforming flawless vehicles into paperweights.

A proper timing belt job on a TDI requires VW/Audi specific software. Without this, timing everything is just a guess. Not to mention all the other mistakes/shortcuts that are common to "professionals". If this "professional" is legit, have him take a look at the car to determine what is wrong.

A real professional on the TDIClub site from your area (MD) is:
Real name: Oliver Wegener
TDIClub handle: TdiRacing
Location: Baltimore, MD
Occupation: Attorney AND Crew Chief RallyVW www.rallyvw.com
I pop test and install Injectors and Nozzles(including PD), Clutches, Timing belts, Brakes, LSD Installs, Do all maintainance and repairs for all TDI models.
Email: [email protected] for info.

 

[Michael Fowler]

Update from the owner.
It now has 140,000 miles.
Timing belt done @ 96k, No problem for almost 45k miles.

Can we dismiss the timing belt as an issue?
How tough is it to check valve lift?

 

[towcat]

how the EGR system? I've been reading up on cleaning clogged systems to restore performance.

 

[02AutoWag]

You can't necessarily dismiss the timing belt. Improperly installed tensioners will hold for a while and let go. Missed timing and you have problems. http://forums.tdiclub.com/showthread.php?t=227009

I'm not here to say that the timing belt is or is not the problem. It's just something to look at since there is doubt that it was done properly.

Have you hooked it up to a code reader? The computer may tell you exactly what is wrong. The VW/Audi specific tool "***-COM" is best, but any OBDII tool should work. http://www.ross-tech.com/***-com/index.html

For any mechanical questions, you should head over to www.tdiclub.com

 

[Michael Fowler]

Thanks, i will forward the information to the owner.

 

[Michael Fowler]

Turns out he tried to have the guru listed above install the timing belt, but he was on vacation and my friend was afraid to wait.

 

[00-7.3]

Is it hard to start ? If so unplug Coolant Temp Sensor and try starting cold. If it fires right up,high probability that belt tension is loose causing cam advance and fuel retard. Likely a big dollar fix with bent valves which would explain rough idle etc. My 2002 TDI is in right now for this because of poor workmanship by VW "stealer" who replaced timing belt.

 

[Michael Fowler]

Another update.

Now it has unburnt fuel coming out of the tailpipe, combined with a slight roughness, possibly a "miss."
What is the possibility that there is a burnt valve that is preventing pressure to get high enough in one cylinder to start the burn process?

 

[Zrock]

Pull off the turbo hoses and shine a light down the intake runner. VW has a problem with those gumming up to the point where you would not be able to stick a pencil in thier. Most of the ones i ever seem were mostly city driven all the time with no hwy miles on them at all. VW need to see some good runs on the hwy once and a while. Its a easy fix just time consuming. You need to take the intake runner off and clean it out. Most of it will have to be taken out by a screwdriver or somethig. Iv seen them so bad that when we took them off you could barley see th elight shining through.