boost problems - following remap

[tim99]

I have recently had an APR chip installed along with a new MAF and dump valve. It went great for a week then went totally flat - slower than before I had the chip installed. It had an overboost fault registered - something it had done a couple of times before the remap. He said the car had gone into limp mode.
I rang the guy who chipped the car and he said that the only thing left to replace that could cause the overboost is the boost controller valve.
I went down with a new valve but bought the wrong type (J N75 valve, instaed of C thet was previously fitted). He fitted this anyway and did a rolling road and told me it was back up and running at 268BHP and boosting a peak at 1.5! (previously he told me I would only get 250 out of a 210BHP model.
I didn't complain but when I drove away it was running just as bad as before - I went back but he didn't believe and sent me on my way.
I went back 2 days later cos I knew it wasn't right and afetr finally coming for a drive with the VAG-Com he admitted that although the car was requesting 1.3 it was only making 0.9(standard).
He said this could be because the C valve was faulty and the car was not suited to the J valve??
I have fitted the old C back and it runs crap, with the J it does run a bit better but not as well as it did when it was chipped. I have a new C on order.
Can a boost controller valve really make this much difference? or is the guy just getting rid of me?

What else could cause this loss in power?
Could the turbo have gone?
I wish I had listened to everybody who told me not to chip it now!

Anybody any advice? I'm in Aberdeen, Scotland so not many choices where to go

 

[recomdos]

damn it! that's pants man! I am of no technical help at all, but I do feel sorry for ya bud! I was worried about buy a chipped car at first. only had it a month and hope nothing major goes wrong with it. was the place you got it done reputable? I hope you get it sorted and I'm sure some people on here will be able to advise. best of luck bud!

 

[tim99]

Cheers, I hope so, I've been using the UK TT forum till I found this one without much joy.

 

[Gambba]

In short yes the N75 can make that much difference. The N75 valve controls the maximum boost pressure reached and if faulty may cause it to overboost putting the car into limp mode. The same can be acheived by fitting a different N75 to the original, which in your case was the J type, which does increase boost pressure over the C and in some cases will put the car into limp.

I would suggest that your fault originally was with the N75 causing the turbo to build up too much pressure, which you then rectified to a certain extent by fitting the J type, but this too at a certain point caused overboost.

So in short go get yourself the standard N75 from the stealer or Vagparts and fit that and I expect all will be good again.

If you are really interested in how much differenec the N75 valve makes then try a search on 'N75' over the last 3 months, and take a look at Glen's (ESS_THREE) post.

As a side note the car goes into limp mode in order to preserve the engine and prevent further damage.

 

[tim99]

I am waiting for one from the dealer who say it will take 7-10 days.
But if the original C valve was faulty and caused the overboost why is it not running ok with the ECU reset as it did before the overboost. I would expect it to run good again untill it overboosted again (caused by the faulty valve).

 

[AndyS3]

hi tiw115

Out of interest who chipped your car?

 

[Gambba]

[ QUOTE ]
tiw115 said:
I am waiting for one from the dealer who say it will take 7-10 days.
But if the original C valve was faulty and caused the overboost why is it not running ok with the ECU reset as it did before the overboost. I would expect it to run good again untill it overboosted again (caused by the faulty valve).



[/ QUOTE ]

Does it not stand to reason that it overboosted on the rolling road? But you should be able to get it out of limp mode by simply switcing off and back on again, and if this isn't the case, then it may well not be down to the N75.....but based on what you said it did improve for a period.

 

[tim99]

I've just fitted the F type N75 (which is the replacement fo rthe C) and it still is running as it did before the remap. The car has new dump valve, new MAF and has had every type of N75 valve under the sun tested and always runs just as it did before the remap.(although runs best with the J valve)
So I have nothing to show for almost a grand.

What could be causing this problem following the overboost a week after chipping?
When I left Star Performance last time they said it was requesting 2.3bar but only making 1.9 what else could cause this?
I think that Star should have known if it was not running well on the J valve then putiing a C back on would not fix the problem as all the threads I find on the J say this is the best.
Any comments?

 

[Gambba]

Well the N75 valve thought was based on the fact that it seemed that you were ok upto a certain point once the valve was changed....but obviously that was not the case.

Why are you sure it's a boost problem? Have you had the same overboost code come up, if so what is the actual code displayed in the ECU memory? If you've got this then I'll be able to direct you in the general direction I would of thought.

I wonder if this could be a wastegate problem that's giving you running problems, which I know can sometimes only become apparent after chipping.

 

[tim99]

I had suffered an overboost before chipping (twice in 6 months or so). not sure of the fault code - max pressure exceeded I think - sporadic fault.

This put me into limp mode (I think) but when the ecu was reset the car did not go back to how it was before and was not making the requested boost as it was before.
So could the overboost have actually caused damage. I did not see the fault code myself but Star Performance just said it was an overboost reset put a N75 J valve on and rolling roaded it. They said it had 264BHP even though it was running as bad as ever straight after??
At present there are no faults stored and it is still running crap.