# Boost questions on 5000CS



## rabbit83 (Apr 11, 2003)

Hello all,
I have been wondering about the boost on my 88 5000 CS TQ Avant.
Usually hits about 1.1 on the guage. Today I was suprised to see it hit 1.2. Seems to be building boost faster as well.
I have the sneeking feeling that my cat is comming apart, I have a rattle from under the car when revving it.
I know the turbo is in good shape I had it checked when had the head off, could I have a sticky wastegate? Would the cat problem cause this? The car sat for about a year before I bought it, it has slipped timing and bent some valves, I put a reman head on it.....
Any suggestions would be apreciated!


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## rabbit83 (Apr 11, 2003)

*Re: Boost questions on 5000CS (rabbit83)*

Wow, no one has even read this????


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## yodasfro (Oct 2, 2004)

*Re: Boost questions on 5000CS (rabbit83)*

Check your vaccum line from the wastegate to the intake mainfold this hose fails do to heat and can cause the WG to stay closed therefore creating more boost.


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## gidrew (Mar 28, 2004)

*Re: Boost questions on 5000CS (yodasfro)*

and to go along with what yodas saying, check your MM hose, and make sure the intake side of thing is air tight. you mite have a rip in the MM hose and its causing the turbo to surge. Also, do yourself a favor and order up a mechincal boost gauge. Jegs.com has mechincal vacuum/boost VDO gauges for like $28. those factory gauges arent very accurate.


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## GTQ (Feb 25, 2005)

*Re: Boost questions on 5000CS (rabbit83)*

Most likely a tear at tha bottom of the intercooler to throttle body hose (aka. michelin Man hose) - or other air leak post turbo. Could also be bad vacuum line(s) or even popped intercooler side(not likely).
Bottom line - you have intake leak(s).
HTH
http://ben_swann.homestead.com/myaudi.html


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## rabbit83 (Apr 11, 2003)

*Re: Boost questions on 5000CS (GTQ)*

Thanks for the tips I will look into them all.
As soon as the weather gets better and I can drive my other car, its goin in the garage for repairs.....


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## Twistedaudi (Jan 6, 2005)

*Re: Boost questions on 5000CS (rabbit83)*

I'm confused: If its hitting 1.1-1.2 bar, than there's no problem with it? If the wastegate were torn, it would be in the ballpark of 1.4-1.5... right up to the point of the fuel cutoff and your face getting slammed into the windshield.
SInce its not overboosting (or underboosting, but much anyway) I think its unlikely you've got a big boost leak. (eg... IMO, unlikly you'ew talking about the MM hose... as evertime I've had one go, it loses WAY more than .1-.2 bar boost. 
Just My opinion: but I highly recommend just pressure-testing it, and seeing what happens. Sound to me like you have a very small leak somwhere. Best of luck man.


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## rabbit83 (Apr 11, 2003)

*Re: Boost questions on 5000CS (Twistedaudi)*

Ok now you confused me, I had always thought that around 1.3 was normal.
The 87 5000 CS Quattro I had a few years back would max out at 1.3, making me think that the 1.1 I am getting now indicated a problem.
I will be looking for that leak when I have the front end off of it later this spring.


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