Mbc Problems

DeAdGnRaTiOn · 10-28-2004

Alright dudes, I installed my manual boost controller, which I think is correctly but this is why I am starting this topic. I also recently installed an after market boost gauge so i can get some accurate readings. When I run with no MBC I am hitting 10psi on the guage...which I assume is normal. When I install my MBC it will hit up to 15, then slowly drop to 10 and stay at ten till i shift, then it will repeat...reach up to 15, slowly drop to 10. I can unscrew the MBC completly or screw it in and it will make no difference. I will always hit 15 and it will slowly drop as long as the MBC is in. When it is out...steady 10. WTF is the problem lol. 1990 Talon AWD Tsi.

I tried unplugging the sensor on the stock boost controller and I have just filled up with 92 octane. I heard that could be a problem...but still no dice.

SuperSleeper · 10-28-2004

Does your car have aftermarket exhaust? Could be boost creep... or there may be a boost leak between the MBC and the wastegate.

DeAdGnRaTiOn · 10-28-2004

stock exhaust but i suppose that wastegate problem could make sense. The hose that is on there is snug, but not as tight as the stock one. Is there alot of pressure going through there?

**Shane@DBPerformance** · 10-28-2004

Quote:

Originally posted by illegaLaser@Oct 28 2004, 05:41 PM
Does your car have aftermarket exhaust? Could be boost creep... or there may be a boost leak between the MBC and the wastegate.

Boost creep is when the boost goes up not down. And a leak between the MBC and wastegate would make more boost. A bleeder style boost controller is essentially a leak.

Check for boost leaks in system from the turbo to the head. You should really do an exhaust before you turn the boost up though.

1QUICK4 · 10-28-2004

Make sure the hoses aren't switched around. Mine was doing the same thing except spiking to 17 then falling to 10. It had been so long since I hooked one up I accidentally reversed the flow lol.

TheBlizzard · 10-28-2004

Quote:

Originally posted by 1QUICK4@Oct 28 2004, 08:01 PM
Make sure the hoses aren't switched around. Mine was doing the same thing except spiking to 17 then falling to 10. It had been so long since I hooked one up I accidentally reversed the flow lol.

And we have a winner. Sounds to me like you hooked it up wrong also.

CRAIG

Alpine TSi · 10-28-2004

But if it was hooked up backwards wouldn't it just keep boosting until the motor popped? Unless he has a really bad boost leak. I have done this once and got to 30psi (where my gauge maxes), then the line blew off and I noticed I was running uber-lean, then backed off. Luckily I didn't kill anything.

1QUICK4 · 10-29-2004

Quote:

Originally posted by Alpine TSi@Oct 28 2004, 10:01 PM
But if it was hooked up backwards wouldn't it just keep boosting until the motor popped?* Unless he has a really bad boost leak.* I have done this once and got to 30psi

He said he was running stock exhaust and mine was a 14b w/ stock exaust. Were you running a bigger setup?

Anyways, listen to the MBC and see if it makes a hissing noise. There was air coming out of the bleeder hole at idle. Something to check out. :goodluck:

Alpine TSi · 10-30-2004

Slightly bigger yes. 16G, 2.5 inch dp and 3 inch catback. Are you trying to say that is all the boost it will build like that?

DeAdGnRaTiOn · 10-30-2004

Hey I will try that and see what happens. Thanks alot dudes!

DeAdGnRaTiOn · 10-31-2004

That was it. Thanks alot guys!!

1QUICK4 · 11-02-2004

Quote:

Originally Posted by DeAdGnRaTiOn

That was it. Thanks alot guys!!

No problem man, glad we could help

93talon · 11-13-2004

the downpipe is after the turbo so that would have nutin to do with it

1slowdsm · 11-16-2004

I guess I'll try to having the bleeder fully closed and the ball&spring screw all the way out. Hopefully that'll do something different so I can atleast have a clue on whats going on.