For the first time in 2 years my car has started playing up :(

[cnut]

I went out to do some shopping last night and I thought I would take the long way home to clear out the lungs of the car. Full throttle on 2nd to the redline all good. Then when I got to third gear the car bogged down at around 3000rpm. I initially thought the clutch was slipping but it was just an almost instant lack of power. The car had hit limp home mode and when it was restarted all was fine.

I hooked the car up to VCDS and it came up with this:

1 Fault Found:

17965 - Charge Pressure Control: Positive Deviation

P1557 - 35-00 - -

From looking this up this code is usually shown when the car overboosts, typically caused by sticking turbo vanes, boost leaks etc.

I went out again and gave the car a damn good Italian tune up and I only managed to get the car to go into limp mode once but after that all was fine. Problem solved? Nope!

This morning I went to start the car and the car wouldn't start. It eventually started after turning over for about 15-20 seconds was a little bit chuggy (but always has been in the morning) for a few seconds and then it seemed fine after that.

I'm planning to get some Mr Muscle Oven Cleaner and clear all the soot out of the turbo. Any other suggestions? What do you think has caused it to struggle to start?

Help guys!!

The car is a 1.9TDI 130 AVF

 

[MooLard]

Good afternoon

What miles does your car on and does it have the original vacuum pipes controlling the turbo and various things on the car? Have you done any work in the engine bay recently?
The pipes are built to last pretty well and have a weave covering, they do perish gradually over time and even a slight leak anywhere in the system will cause poor operation and control of the turbocharger. You might not be able to clearly see the split pipe or pin hole either.
It's only a possible suggestion but I'd recommend replacing all of the vacuum pipes, I got a few metres of the silicone / rubber stuff from an auction site, think it was 4mm inner diameter. If you replace them one at a time it'll help you keep track of the route they go and what is linked to what.
As for oven cleaner, my turbo hasn't ever got that bad but upon purchasing my car I did take the manifold to EGR pipe and got as much oven cleaner in there as would fit before cranking the engine a few times. I didn't personal feel a difference but I am aware others have seen some benefit from this, and for the low cost and effort it's worth a punt.

 

[cnut]

Thanks for your reply MooLard,

My car is nearly on 118K and as far as I know all the pipework is original excluding an intercooler pipe which I replaced last year as it was on the verge of splitting. RE engine work none apart for an oil change that I did myself last year. I will have a good look at all the pipework at the weekend and see if I can see anything adrift. Thanks for the tip on cleaning the EGR and manifold this was something I was thinking about doing at the same time depending on the weather!

I have a hunch it's definitely a build up of carbon which is causing the problem. When I bought the car 2 years ago I had the intention of using it a lot more than I currently do and that combined with 2x 3min round trips to work 5 days a week for the last 2 years probably isn't doing the turbo any good due to the carbon build up. I think I might get rid of it this year and get myself a petrol car again!

 

[dulux72]

I've just had the very same problem with an A6 avf 130 tdi.
It's unlikely to be a hole in a hose as the car is entering limp mode due to an over boost ie too much boost.
I cleaned the turbo with Mr muscle to no effect and ended up trying innotec turbo cleaner again with no effect.
In the end I replaced the turbo actuator which touch wood seems to have solved the problem

 

[cnut]

I've just had the very same problem with an A6 avf 130 tdi.
It's unlikely to be a hole in a hose as the car is entering limp mode due to an over boost ie too much boost.
I cleaned the turbo with Mr muscle to no effect and ended up trying innotec turbo cleaner again with no effect.
In the end I replaced the turbo actuator which touch wood seems to have solved the problem

That's good to hear you have solved your problem. I have read about the actuator playing up which can cause problems too. Did you try cleaning it whilst you cleaned the turbo? Because I heard they can seize up causing problems with controlling the vanes.

 

[dulux72]

Whilst cleaning the turbo on both occasions I made sure I disconnected the actuator and manually moved the vane lever to ensure it was free moving. The problem would return under load in 3rd or 4th. It was almost like the actuator would stick in the fully open position. Hence causing the turbo to over boost as it couldn't shave off boost by closing the vanes.
Anyway I replaced the actuator with a new one and set it up exactly the same as the one I removed.
After 2 weeks of over boosting once I replaced the actuator the car has been fine ever since.

 

[pauldazzle]

It's important when using the MR Muscle method of freeing up the vanes to leave it in for at least an hour, & to keep operating the actuator during this time until it has full movement & feels smooth. BTW disconnect the actuator vacuum pipe or it is very difficult to operate it.

 

[pauldazzle]

As already stated replacing all the braided pipes is good practice, but wouldn't be the cause of the overboost problem.

 

[desertstorm]

Check the glow plugs for your starting issues possibly one or more duff. Quite possibly the turbo coked up with your driving patterns certainly not helping. The best and really only way to clean the turbo is to remove it and strip it. Anything else is just a temporary measure and will not do as good a job.
If you have VAG-COM try logging the boost and post up the results. Over boost can be a result of a duff MAP sensor as well but if you log the boost this will usually show itself up with the car reporting 2 bar of boost at idle.
Log groups 10 and 11 from idle accelerating through the gears to 60-70 mph.

https://sites.google.com/site/1810martin/vcds-and-pd-tdi-engine-health-check

Karl.

 

[cnut]

Check the glow plugs for your starting issues possibly one or more duff. Quite possibly the turbo coked up with your driving patterns certainly not helping. The best and really only way to clean the turbo is to remove it and strip it. Anything else is just a temporary measure and will not do as good a job.
If you have VAG-COM try logging the boost and post up the results. Over boost can be a result of a duff MAP sensor as well but if you log the boost this will usually show itself up with the car reporting 2 bar of boost at idle.
Log groups 10 and 11 from idle accelerating through the gears to 60-70 mph.

https://sites.google.com/site/1810martin/vcds-and-pd-tdi-engine-health-check

Karl.

Thanks for that, here are the logs: EDIT: I can't get these to display properly. What's your email address and I will send you the file.

 

[desertstorm]

PM sent

 

[pauldazzle]

Thanks for that, here are the logs: EDIT: I can't get these to display properly. What's your email address and I will send you the file.

This should help you. https://sites.google.com/site/1810martin/how-to-turn-a-vcds-log-into-an-excel-graph

 

[cnut]

I just wanted to update this. I have since decoked the turbo with Mr Muscle Oven Cleaner and then given the car a very hard drive. No more overboost issues and the car is MUCH less smokey than it use to be. Lesson learned - no more nursing the car to save fuel and no more short journeys!

 

[MooLard]

Nice one thanks for the update, The oven cleaner operation seems to makes for mixed results for people, but for your situation it's great that it has done the trick. I frequently do short trips in the week but every few weeks on longer trips, once the car has been at full operating temperature for several miles I do then to wide-open throttle finish off third gear to try and clear the cob-webs out and burn off any excess carbon deposits.