Overboost issues, turbo has been cleaned

[pistol pete]

I have a big issue with over boost then car going into limp mode.

I cleaned the turbo out twice now. It still does it.
Either when pulling away then when it hits 3k in second gear, or the other day going up the m20 hill towards london, then wouldnt go above 40

Need to get this sorted, what do i need to check and look for?

Its a 2004 dsg 140tdi

Any help would be brilliant

Code reader just brings up over boost
Many thanks

 

[s5joe]

map sensor maybe

 

[pistol pete]

Hmm.. i "think" i have changed it already.. been chasing the fault for a while.. i will ask the wife as she has better memory than me .. oopss..
Im pretty sure i have already changed it

 

[AndrewBates]

make sure theres no excessive amount of oil in the intercooler, could cause your engine to run on

 

[mookster]

Mechanically, overboost would be caused by the wastegate not venting off enough excess gas which then has to carry on going through the turbo instead. Might be worth checking your wastegate is working properly, could be a leak in a vacuum pipe to it causing it to stay shut for longer possibly. Electronically it could be any number of things that could be causing it to stay shut; relays, sensors, etc.

 

[pistol pete]

I have noticed the pipe into the intercooler has a tendancy to "pop off" everynoe and again then re seat itself, the clip looks okay but doesnt seem to hold it..
I am guessing this could casue it.. making it work hard to get boost, then re seating and spiking the boost?

 

[mookster]

A leak in the pipe work post-turbo could lead to overboost in the sense that the turbo will be spinning up more than it should, though it would feel like it has less boost when driving - much like trying to blow up a balloon with a hole in it, you can huff and puff all you like, but it'll never properly inflate

 

[pistol pete]

Cool.. i thought i had solved the issue with that pipe.. ill get up on jacks to orrow and check it..

I will report back

Thanks

 

[pistol pete]

I have checked and the boost pipe is secure so that isnt the issue.

I will say though the car /turbo sounds like a police siren!

Is it the turbo on way out what can i do? Or worth chaning map,sensor or could it still be a boost leak?

Thanks

 

[mookster]

Always difficult to tell these things without seeing/hearing it first hand. My experience is also with petrol turbos so not quite sure how it relates. That sound still suggests a possible leak if it's spinning up too much and not providing boost. It could also suggest broken blades on the compressor side if it's spinning but not boosting Think you'll need someone with the proper gear to take a look

 

[pistol pete]

Oh it boosts.. and goes really well
It hasnt done it this week since it went to limp mode at weekend
Still noisy though..

Yeah i might have ask around.. ill get up on my ramp and have a good butchers at it

Thanks

 

[adamss24]

If it started whining then you might want to change it before it runs on oil and destroy the engine !

 

[NHN]

How did you clean the turbo is the 1st question tbh.

 

[pistol pete]

Used the turbo clean stuff recommended on here..
Take downpipe off.. spray first stuff wiat.. then clean it out..

Goes quieter for a couple weeks after then comes back
Doesnt use any oil

 

[NHN]

That's what I thought & its a total waste of time doing that way, temporary at best, turbo of, strip, clean properly, rebuild, problem solved.

 

[pistol pete]

Okay thanks... ill look into doing that then...
If i have got it off is it worth sending away to hybrid it? Anyone know rough costs

 

[NHN]

Turbo dynamics AFAIK sell new units hybrid converted, not sure they would do existing.

I've done the clean for numerous clients & never had a comeback.

 

[pistol pete]

Where abouts are you based?
Thanks

 

[NHN]

Usually I come to clients, is it a quattro?

Whereabouts are you located?

 

[pistol pete]

Nope its not a quattro, and im south kent....

thanks

 

[NHN]

Location is fine, pm me if you are interested in this service