[Clownaround]

Hi, I'm trying to track down a boost leak which is progressively getting worse as time goes on...

I used to get and hold 18psi on an MHD tune with the occasional 30ff but lately get the dreaded 30ff /yellow engine symbol and can't get past 8psi while hardly pushing the car....I have recently replaced ALL of vacuum hoses even the ones running to wastegates and under engine cover. I am running an ER Chargepipe and Tial BOV (yes I remembered the O-ring)

I've read all of the previous posts and have tried both the Smoke (grape swishers) test as well as the Air Compressor/ spray soap / listen for leaks test.

Smoke test was inconclusive never saw any smoke after trying to pump several lit cigars through the system.

Air Compressor test showed no leaks. Sprayed everything down multiple times even the intercooler pipes under the car.

HERE IS THE ONLY THING I DID FIND.....while useing a compressor leak test from 5 to 10 psi once the system pressurizes I hear a loud air leak behind the engine on the Turbo side. I have put my hand as far back as I can but cannot feel any air leaking around the rear wastegate. Is this my leak? Where is it coming from? How can I fix it? Any thoughts? Or am I way off base here?

Thanks

[Flex68]

Leaking pcv vent hose ???? Or valve cover ?

[Levanime]

logs?
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[Sgop335]

Originally Posted by Clownaround

Hi, I'm trying to track down a boost leak which is progressively getting worse as time goes on...

I used to get and hold 18psi on an MHD tune with the occasional 30ff but lately get the dreaded 30ff /yellow engine symbol and can't get past 8psi while hardly pushing the car....I have recently replaced ALL of vacuum hoses even the ones running to wastegates and under engine cover. I am running an ER Chargepipe and Tial BOV (yes I remembered the O-ring)

I've read all of the previous posts and have tried both the Smoke (grape swishers) test as well as the Air Compressor/ spray soap / listen for leaks test.

Smoke test was inconclusive never saw any smoke after trying to pump several lit cigars through the system.

Air Compressor test showed no leaks. Sprayed everything down multiple times even the intercooler pipes under the car.

HERE IS THE ONLY THING I DID FIND.....while useing a compressor leak test from 5 to 10 psi once the system pressurizes I hear a loud air leak behind the engine on the Turbo side. I have put my hand as far back as I can but cannot feel any air leaking around the rear wastegate. Is this my leak? Where is it coming from? How can I fix it? Any thoughts? Or am I way off base here?

Thanks

Sounds similar to mine, but im boosting better now. I have still not ruled out my turbos, but one boost solenoid seemed to be an issue. As for your loud air leak could be the intake to your rear turbo?

[Clownaround]

Originally Posted by Sgop335

Sounds similar to mine, but im boosting better now. I have still not ruled out my turbos, but one boost solenoid seemed to be an issue. As for your loud air leak could be the intake to your rear turbo?

Yes I think I remember reading that the rear turbo inlet/intake is the weakest link when running a pressure test but why is it leaking at such low boost? I cant get my hand back far enough to try to hold it in place while running test.

I guess I could try getting a boost solenoid and swapping it out with one or both to see if they are bad. Those things aren't cheap been putting it off.

I will try to grab a log this morning and get it posted up.

Thanks for the suggestions guys

[Clownaround]

Here is a log from this morning. Yes it triggered 30ff code. Only reaching 8psi

http://www.datazap.me/u/clownaround/...a=4-25&mark=28

[mojobmw_e90]

Check turbo inlets front and back and also check the turbo side coupler that connects to intercooler and upper turbo pipe on passanger side. If you have a after market intercooler and this clamp wasn't positioned right that will always cause a boost leak

[Clownaround]

Unfortunately its hard to get a visual on the inlets. Although the sound of air leaking does appear to becoming from the area of the rear turbo. Its quite loud and will eventually stop, once most of the air is out of the pressurized system during a compressor test. I am running a stock intercooler and stock turbos.

[Clownaround]

Took the chargepipe off as well as the intercooler connections under the car yeasterday. Wiped everything down performed a soap spray compressor test and reseated everything back together. No visible air leaks or noises other than the sound of air escaping behind the engine somewhere. If I could only look back there or get to it easier..

[Sgop335]

Originally Posted by Clownaround

Here is a log from this morning. Yes it triggered 30ff code. Only reaching 8psi

http://www.datazap.me/u/clownaround/...a=4-25&mark=28

yea surely that will throw a 30ff. Agreed, I been unable to check my rear inlet as well, will try using a borescope this weekend.

Solenoid...there is a good way to check its operation, no need to just replace them yet. Try searching otherwise I can post the procedure and values to expect. Just did this.

[Clownaround]

The more I read about faulty boost solenoids the more I feel this may be the root of my problem. I'm going to see If I can test them out. I just need to find a vacuum guage.

[mxchris727]

If it's not the boost solenoids, then your wastegate vacuum actuators are bad.