Jeff_DML

The last few months my A4 1.8T hasnt been feeling like it has been making full boost. Even when I switch between my stock ECU and my APR 1.0 I dont notice much of a difference between them. I used to remeber a huge difference when I switched them. It doesnt feel dog slow but not fast. I got beat by a 323 wagon a few weeks ago so its bugging me.

I bought a boost gauge from AWE and installed it. According to it I am not make more then 5psi of boost. I wasnt sure if I installed it incorrectly so I reinstalled it, checked for kinks, etc. Still no more then 5 psi of boost. So most likely the gauge is correct.

AFter reading all these stories about diverter valves tearing I decided to switch it out with a new one. I installed it and still no more then 5psi of boost.

I have been running 92 octane gas since I bought the car new and running the same gas from the same station. I do not have the VAG DTC software so I cannot check for any faults but no check engine lights are on. Limp mode is supposed to very noticeable. I have also looked in the engine compartment for any loose hoses and I havent seen any. I dont know what I am looking for though.

Any suggestions what I should do? I am out of warrenty with about 50k miles.

Thanks
Jeff

Perpetual Novice

is there a hole in your intercooler? split hose? vacuum leak?

Jeff_DML

I didnt notice anything

eharleq

than the rod. Even the 323GTX maxes out at 180hp.

Jeff_DML

BMW 323, plus 98.5 A4

Paul H. (near Annapolis, MD)

I had the same thing happen, except I was only making 3 PSI of boost. Turned out to be a loose vacuum line. I have also had one of my turbo hoses leak on me (same thing -- loose connection).

What year is your car? I have seen at least one turbo hose crack/burst near the junction of a narrower line leading up to the BPV. On the older cars, this line can be rather long and convoluted.

From my experiences, since you are producing at least some boost I would say there's a good chance your turbo is ok. I'm not a turbo expert, but most of the turbo failures I have read about here, including wastegate rods, were total failures (0 PSI to vacuum). I believe there was at least one with turbine damage that was still making some boost. Someone please correct me if I am wrong.

See if you can get your intake system pressure-tested. Make double sure you don't have any leaks.

Paul

Cool Craig

...and I have very little boost. The rod is usually easy to detemine, listen for a rattling sound when the idle comes down, after a rap of the exhaust, this should occur with or without load. I have no performance gain with either chip in my car, a TAP or APR, in fact, the APR software encoded P Box is acting strange, car stalls at 3K, re-ignites when in gear, stalls if in neutral. So many problems lately, I just wanna get stoned and forget about it until the weekend.

Jeff_DML

Thanks for the very good response, I am a 98.5 like you