[pits200]

I am in the process of diagnosing a boost issue. I was at the strip and my car was running perfect at 17.5 psi, all of a sudden boost cut to 9psi.

No codes were thrown. On the drive home, boost stayed around 8psi with no weird sounds or smoke.

Now I have 0psi and doing a boost test from the hot side of the IC the car has a hard time getting past 10psi on the boost gauge.

I am using a tire connector so pressure doesn't stay it leaks out in about 15 seconds to 0psi. The bugger is, there are no ic leak issues with the cp, dv or throttle body or maybe I just can't hear them but they're whisper quiet.

The main sound I hear is a hissing from the intake manifold nearest to the front of the car.


I need some opinions, this is frustrating.

[JamesM3M5]

Something that leaks that badly would be an obvious leak. From 17+ down to 9 with no major leaks sounds like it may be a control issue or a bad turbo?

For boost leak testing, I typically have a regulator set to about 15 to 20psi and leave the pressure on constant.

Do you have the capability of logging a simple 3rd gear pull? Look at throttle position, wastegate duty cycle, and boost.

[pits200]

Originally Posted by JamesM3M5

Something that leaks that badly would be an obvious leak. From 17+ down to 9 with no major leaks sounds like it may be a control issue or a bad turbo?

For boost leak testing, I typically have a regulator set to about 15 to 20psi and leave the pressure on constant.

Do you have the capability of logging a simple 3rd gear pull? Look at throttle position, wastegate duty cycle, and boost.

I literally have no boost now, zero. I have no whistling from the turbos and no oil from the exhaust along with no codes. I moved the front and rear wastegte with my vac pump and the the actuator moves smoothly at about 8hg I think.

I'm stumped, It has to be on the hot side I'm guessing. As for boost leaks, it can't be something on the cold side, I agree or the leak would be very noticeable which it isn't.

[cn555ic]

Did you check the intake manifold nipple near throttle body.

[pits200]

Originally Posted by cn555ic

Did you check the intake manifold nipple near throttle body.

Ya, that was my first guess since I know it's a pretty cheaply built and easy to break. I got soap and water but no bubbles anywhere, even around the intake manifold.

[cn555ic]

Best to do a smoke test and have the car under load to see boost leak. Having soap and water without engine under load will not show you where the leak is coming from

[pits200]

Originally Posted by JamesM3M5

Something that leaks that badly would be an obvious leak. From 17+ down to 9 with no major leaks sounds like it may be a control issue or a bad turbo?

For boost leak testing, I typically have a regulator set to about 15 to 20psi and leave the pressure on constant.

Do you have the capability of logging a simple 3rd gear pull? Look at throttle position, wastegate duty cycle, and boost.

This is the best I could do..

[Jeff@TopGearSolutions]

After you spray all connection from the charge pipes and tmap and any other locations, it's possible you cracked the bottom of the intake manifold, rare but possible.

[pits200]

Originally Posted by Jeff@topgearsolutions

After you spray all connection from the charge pipes and tmap and any other locations, it's possible you cracked the bottom of the intake manifold, rare but possible.

Could be possible, I haven't pulled it off but I'm guessing that the hissing I was hearing was the air in the cylinders and going over the valves.

I already changed one of the boost solenoids, changed the vac lines to both front and rear wastegates. Changed one of the vac canisters, both of the vac lines going to the brake booster and checked all the cold side connections.

When I hook up the Procede, my radiator fan goes on crazy high and I get a 12000 (2ee0) code.

But when the car is stock, I dont get that code. This is all very odd to me right now. I've installed and removed the Procede about 4 times now.

I have no idea what the issue is, it doesn't sound or smell like a bad turbo but I'm out of ideas.

[M3 Eater]

Check vac tubes under engine cover. I bet one has burst or collapsed

[cn555ic]

If you hook up the procede and the fan turns on like super max speed then you have one of the connectors on wrong.

[pits200]

Originally Posted by cn555ic

If you hook up the procede and the fan turns on like super max speed then you have one of the connectors on wrong.

Thats what I figured but how the hell is that possible, its such an easy install. I have additional meth connections that are incorporated but I've done this like 50 times in the past year, I'm not sure what can fit wrong. Also, it makes a loud buzzing sound when its in the start 2 position where the gas gauge moves but the engine isn't on.

Black connector goes to black connector, white to white and so on, what else could I be missing.

Is it possible that a fuse went south?

[pits200]

Originally Posted by M3 Eater

Check vac tubes under engine cover. I bet one has burst or collapsed

I wish it were that easy, I've changed those already.

[cn555ic]

If you connect one of the pins off it will do that. Ask me how I know! If your off one pin it will stick connect back into subconnector!

[jpsimon]

I had a boost leak on the bottom side of the charge pipe on the side that connects to the intake manifold. It was very hard to see but a little bit slipped off... worth checking out unless you already have and i don't know because I didn't read the thread

[pits200]

Originally Posted by cn555ic

If you connect one of the pins off it will do that. Ask me how I know! If your off one pin it will stick connect back into subconnector!

Haha, thanks for all the pointers, back out to the garage I go.

[JamesM3M5]

Maybe reinstall the firmware and reload the map on the Procede??

[pits200]

I give up.

I have very strong vac when I disconnect the brake boost cable. But I still only get 7-8 psi at full throttle and I am now hearing a loud whistle which I'm guessing is from one of the turbos.

I get the 12000 code still and the fan sounds like a jet about to take off. I checked the Procede cables at least 5 times and reinstalled all software but to no avail. I keep getting the buzzing sound from the front of the car when the ignition is one step from being on.

What a productive day....

[pits200]

Originally Posted by jpsimon

I had a boost leak on the bottom side of the charge pipe on the side that connects to the intake manifold. It was very hard to see but a little bit slipped off... worth checking out unless you already have and i don't know because I didn't read the thread

Thanks, that is one of the first ones I checked but there is definitely no leak there.


Can anyone tell me what are the symptoms of a failing turbo? Would it just be instant because I never had any possible symptoms with my turbos as of last week.

[335i-boy]

Interesting problem. Sorry it has happened to you.

It sounds like a boost leak. I have had the fans on full blast. Whilst crusing at 65mph got a limp mode. When I pulled over the fan was on continuous and at max. Just turned car off and on and car was fine. Can you take the car somewhere where they do a smoke leak test? The leak may be small and invisible at idle speed but when driving at under load the sound of the engine may drown it out.

Keep us posted. I am sure that there would be a few of us that would like to know what the outcome is.

[Bme30]

I'm kinda in the same spot.....at least maybe. My car holds boost and runs pretty good, but I'm not making the power I believe that I'm suppose too.
I have been reading about checking the lines and Everything. All my lines are brand new. One thing I just noticed is that when I pull my boost line off the brake booster canister to check for vacuum I have a nice hissing vacuum. But the weird thing is that I hear a hissing noise from around the oil filter housing???? Any ideas??? Is this normal??

[pits200]

I never updated this thread, the site reminded me that this thread was being viewed so I might as well update.

This problem was when the c-clip fell off my front turbo disconnecting the wg arm leading to no boost. Luckily I was able to rig a contraption to reconnect the wg arm and install another c-clip. Cheap fix but spent about 3 hours on my back trying to reach the arm and connector.