Volkl

So, my turbo has sounded funny these days. It used to be a very distinct whir. Now, it sounds like sucking. No performance difference, no funny noises, nothing, just a change in the sound. It just sounded different one day. Any suggestions as to what is causing this?

A little more detail: I have been having boost problems since I chipped the car. I cannot seem to be able to boost consistently. Ex: highway driving, 6th gear, floor the throttle. Turbo spools to 5psi, stays. I quickly take my foot off, floor the throttle again, will spike 20-23psi. Sometimes this happens, sometimes not.

Some times the boost spikes at 15, sometime 23. It is very inconsistent, and has been since chipped, like I said. Hopefully it is the DV or something of the sort. Its a 225 w/ GIAC software

JustAdam

Is this Matt? I think someone should help you here - ANYONE?

InTTruder

Leak between MAF and turbo maybe? At 0 boost, you're hearing vacuum?

TTschwing

Since you got chipped, but dunno how thong that's been. Easy solution it sounds like..

Classic sypmptoms of a weak MAF. The 5 PSI then having to hit the throttle again is classic soft limp mode. Inconsistent boost is often because the MAF signal will not support what you are asking of the car. MAF's often fail out after a performance mod as they are stressed and pushed over the edge. Demands on them were not so high prior to chipping in this case. You can test it with a VAG, but honestly, if it's more than 4 years old and has 40K or more on it, you're probably due.

02TTK04

Vag it to be sure, but sounds like a failing MAF.

Lowcountry

I had a very similar problem last week. My boost levels weren't as low as yours, but I would peak high and fall off to really low levels very quickly. I switched out the MAF per Steve's recommendation, and the problem was solved. In fact, I think that I had had a weak MAF for several thousand miles, because the car pulls harder now than it ever has before.

PS. Buy a remanufactured one.

Volkl

Yea, its me Matt. Vag'd it tonight, it was clear. I think I am going to swap out the MAF and probably the DV valve. I've been running the chip for 10K miles now. I also think I may have an exhaust leak, gonna check that out too.