Audi A4 2.5 TDI V6 1998 AFB lack of power - help

[turbozx]

Hi I have had my audi for 12 months/ 10000 miles now and I have not been able to get to the bottom of the problem.

The car will only rev to around 3000 rpm in gears, top speed of 75mph, it will rev to 4000rpm in neutral.

Starts fine when cold, can take a few more seconds to start when hot, all glow plugs are broken!

Air fiter has been changed
New MAF (bosch) fitted (although this does show signs of being faulty but performed the same as the old one)
EGR blanked off
All pipe work checked for leaks, splits.
VNT mechanism is very loose and not sticking
VNT actuator seems to go up and down ok

1 error code on Vag com - 00550 start of injection regulation - control limit surpassed - intermittant.

No smoke but if i rev it to 4000rpm in neutral it will puff out a cloud of black soot.

Cam belt was changed by previous owner but i dont think he would have checked the pump timing, I only have free VAG COM so can't check it either.

Does this fault sound like pump timing if so how is it adjusted?

Thanks in advance

 

[PAULF]

The short answer is that yes, unfortunately, you check it with VagCom!

However the longer answer,

At the bottom of the engine, on the left hand side is a plastic plug. Remove this plug and turn the engine by hand until the diesel pump timing holes line up. Now stick your finger into the hole, and you should feel a hole in the crankshaft that should be reasonably lined up with the hole in the block. I can't remember if you can be 180 degrees out, so if you can't feel it, turn it around again. This will show the timing is close.

You can hear a real 'bark' or crack when running if it is too far advanced.

You CAN check the timing via VagCom Basic settings, without the timing graph. Go to Basic setting Block 4. The engine will 'hunt' as the pump advance solenoid is operated. When it is 'retarded', the setting in zone 3 should read 0 degrees to 4 degrees ATDC. If you do not go to basic settings, the advance solenoid will be operating, rendering your efforts useless. This solenoid is 'out of range' of adjustment on yours at the moment as the crankshaft angle is more than 3 degrees out of spec. for injection (timing) which is giving your code.
If your free version does not allow you to check Basic settings, a very rough indication can be found in Measured block 19. The values in zone 2 should read between 2 degrees ADTC to 4.7 BTDC. Higher than 2.0 degrees ATDC means it is too far retarded. This is a recorded value from the last start.

Google will give some good guides on the actual pump timing adjustment process. I use an Allen key, and a socket turned with a set of stilsons to adjust and tighten the tensioner.

 

[turbozx]

Hi Thanks for the response, so you think that the pump timing is the cause of my problems? could it also be cam shaft wear?

I can't switch to basic settings in the free version but block 19 reading 0.9 BTDC

 

[PAULF]

Bad news for you is that 0.9 BTDC is within spec for start, although this is only a very rough check. You now need to get a proper timing check done as the next port of call.
Although a genuine cable is expensive it could be worth you buying one now, before you pay out for any checks to be done. (you can always sell it again if you finish with it) A couple of scans and you have got your cash back.
If you can't afford one, try looking at the VCDS map and see if there is somebody near you with a cable and PM the member. Failing that, try a 'Please can anybody near xxxxx scan my car for beer tokens' type thread on the VCDS or B5 section.
Before I bought my KII lead (the slightly cheaper one that only does older cars) I paid £40 for a local Audi independent garage to check my timing that I had set by ear/starting. I thought it was too far advanced due to the 'bark' - it was, but within spec. If you have to pay to adjust it, I would not expect it to take more than an hour.
You can see that it doesn't take long to get back your £200-£300 for a lead at that!

I suppose worn cams could cause your timing to be out, but you still need to check the timing first. There is no point jumping in at worn cams at a huge cost without checking through the basics first.

Ideally Adamss24 will see this thread, as he is the forum 2.5TDi guru - I have a little experience as I have two cars with this engine, but he rebuilds them.

 

[turbozx]

Thanks for the response, I have looked on google and cant seem to find a guide for how to adjust the timing, is it as involved as changing the timining belt ie. does the front end and rad need to come off?

 

[PAULF]

No. The left hand cover needs to come off.
It's been a while, but basically:-
The adjuster slackens with an allen key through the centre and a socket in the stilsons. Turn the socket, and hold the centre with the allen key
Slacken the three bolts on the left hand cam and adjust. Tighten up the adjuster, keeping the adjuster pointer aligned.
Check timing, and repeat as required.
Keep looking on the net, I found a guide with pics somewhere!

 

[turbozx]

the other thing i forgot to add when i was looking on VCDS block 3 or 4 the cold start valve seemed to stay at 100% duty cycle even though the car was warm.

Would this have any effect and how does the cold start work?

 

[adamss24]

You don't need to slacken the tensioner for pump timing, only needs the 3 bolts then move the pump sprocket to the left to ****** and to the right to advance. Some pumps have a shaft that protrude from the flywheel and some does not- on these you will need to remove the flywheel unless you have some big long nose pliers. Tiny adjustments are essential as they make big difference.
The injector pumps also wear internally and they will require a rebuild sooner or later but, i would take the rocker cover off on driver side and check the camshafts condition. If worn then that's your power loss. I had various a4 and a6's with the v6 tdi engine and the loss of power can be a Maf, gunked turbo, faulty boost control solenoid, EGR stuck open, tired pump, worn cams and lifters, faulty MAP sensor, faulty accelerator position sensor and boost leaks- just to name a few. Without VCDS it's quite hard to troubleshoot power isues...

 

[PAULF]

You don't need to slacken the tensioner for pump timing, only needs the 3 bolts then move the pump sprocket to the left to ****** and to the right to advance. Some pumps have a shaft that protrude from the flywheel and some does not- on these you will need to remove the flywheel unless you have some big long nose pliers. Tiny adjustments are essential as they make big difference.

Right enough, I forgot that on mine I was a tooth out to start with, so that was why I slackened the adjuster!

 

[Mal]

Bought this car recently and didn't really notice there was a problem at first.

99,000 miles with a good service history. Multitronic.
The car will only rev to around 3000 rpm in gears, top speed of 80mph, it will rev to 4000rpm in neutral. Does not pull up hills.

Starts fine when cold, can take a few more seconds to start when hot.

New MAFsensor fitted 4000 miles ago and tank fuel pump. New timing belt 1000 odd miles ago.
Had a turbo fitted 25000 miles/ 4 years ago. Local mechanic suspected the car had been "babied" and has just used a Turbo Clean Kit. Even though he says the Actuator is now has a lot more freedom than before the car is still the same. It has the following fault codes:

01441-158 Sensor for low fuel level - G210
17978 P1570 Control module locked
00523-030 Intake air temp sensor - G42
0053 - 031 Air mass sensor - G70
01176 Key fault low signal. ( I have started using the spare now)

Next step is to change the MAF sensor but he is not sure that this is the problem as fairly new fitted and also the other codes that he is not sure about. I would try to clean the MAF sensor but can't get hold of a anti tamper torx. Tempted to buy a cheap MAF sensor from ebay to try.

Any help appreciated!