WTF have they done to my car? turbo cutting out at random after service

[akash_sky1]

ok this is getting annoying.
After an underboost fault code was recorded recently, taken after a cambelt service on my car , and after which there was a huge loss of power and erratic idle. Soon the power less went away, and the car was back to its normal self powerwise ( although still down on power as it turned out the diverter valve was not up to holding the increased boost of the remap).
Now I have had the updated 'D' diverter valve fitted, and the power is huuuuge +40 bhp easily now its boosting properly.

THEN THIS MORNING FOR F*** SAKE, started the car, took longer to start up then normal, accelerated hard a few times :-D. Then after idling for a long time and pulling away notived there was no turbo action at all, no power :-(. No warning lights however. Then restarted, turbo spooling up now, car rapid as ****. Then a couple more times the turbo just cut out when accelerating, restarting engine fixed the problem.
Very similar to the problem on by BORA PD130 when the vanes stuck open. ( or closed was it?)
Restarting fixes problem then came back couple times.
This NEVER happened before. The minute i drove it away from garage 2 weeks ago, there was a similar lack of turbo, which only returned to 'normal' after 1 hour.
Please help, what do you think? im reluctant to leave this garage as they look after me well in the past, but I think they are gonna be cluless when I have to go back AGAIN to fuc*in get this sorted.

 

[navnayyar]

car is going into limp mode, could be a number of reasons. boost/thrust sensor is common, try replacing this, £25 from euro car parts, about 40 from stealers. also as before check for air leaks

 

[akash_sky1]

cheers will suggest that, gettin rite on me tits this

 

[gaz m]

Hi Akash

Your problem is electronic mate, the turbo is mechanical and will always spin as long as the engine is running and producing exhaust gas! unless as you say on your pd130 the turbo was stuck, or was that the waste gate stuck open?

Go back to when the initial problem started after the cam belt change! I have not done one on the Audi but I understand engine mounts need moved on one side of the engine so a fair bit of work and lots of parts moved or disturbed!
There is a very big chance this is where your problem lies something was disturbed or not put back properly or possibly wiring miss-rooted when the engine was put back together or even the new DV is faulty? check over or ask the garage who did the work to go back over the area's the work was done also is the engine Earth strap in the same area as the work was done? possibly low voltage to some engine sensor's if it has not got a good electrical path?

If it is a mechanical fault is there a possiblity the garage bent the Turbo wastegate arm when they jacked the engine up? however I would expect that to be a constant fault that did not reset by turning the engine off and on.

I hope this helps a bit, it will be a simple fix but might take a bit of finding as it could just be a faulty electrical conector that hasent clicked back correctly when the work was done.

Gaz.

 

[gaz m]

One more thing to look at Akash

Check out the EGR valve this lets exhaust gas back into the air intake side of the engine on overboost, it may be stuck open! this gives a poor tickover at idle ( hunting idle ) and may reduce the exhaust gas pressure to the turbo so it dosent spin up properly?

Gaz

 

[akash_sky1]

I know i've mentioned the EGR to them but there's no codes coming up relating to that and I think without seeing a code the guy's just clueless what to do. Seriously thinking of a new garage after this but my warranty's running out soon and obviously need this garage to fix the problem they caused. I'm pretty sure its a minor thing but its so ****** annoying always back & forth to garage.
cheers for your help

 

[gaz m]

not sure EGR would show a code?

You might see it on a live reading, as underboost and possibly a cylinder missfire at the same time on tickover?
It is so anoying and costly when mechanics have no idea what they are doing!!
Gaz

 

[akash_sky1]

going in tommorow hope they fix the damn thing. its ****** annoying when im booting it and enjoying it at full potential for a change,,then it goes into limp mode...

 

[warren_S5]

n75??? maf sensor??

 

[akash_sky1]

It only happens when I boot it longer then a couple of seconds, so it seems boost related? if i just cruise a long for ages then accelerate moderately its ok.

 

[akash_sky1]

Mechanic took some logs and says the boost was spiking all over the place so is going to replace the N75 tommorow finger crossed it works i want my Audi back...this Mini is damn slow and noisy as hell!