Not Holding Boost

abhattan · 01-05-2007, 11:39 PM

Hello again. I need a little wisdom here. I have a '90 MK3 Turbo. The car is not holding boost. If I accellerate slowly, I get a stuttering or chattering a little above 2lbs. If driven hard, it holds boost. It almost felt like clutch chatter, but it only does it a little into boost at any RPM range. Could it be the wastegate? Stock Turbo, 142000 miles.

IHateHacks · 01-06-2007, 03:02 PM

Stock Turbo, 142000 miles.

There's your problem. By the way you are describing it, it sounds like excessive shaft bearing play on that sucker. You can check it by removing the air box/MAF/accordian hose that goes onto the compressor housing (inlet) of the turbo and with your index finger and thumb try wobbling the compressor wheel shaft. The spec is something like .13 mm so any play at all is not good.

Only other way you won't hold boost is a vacuum leak. Try checking the vacuum hose that runs to the wastegate actuator.

drmmr15 · 01-09-2007, 05:10 AM

How do you get to that hose?

IHateHacks · 01-09-2007, 04:18 PM

Take off the big rubber hose that goes from your MAF sensor to the compressor housing. We usually call it the accordian hose because it has ribs in it that looks like an accordian. It will be staring you in the face then.

Supra2NR · 01-10-2007, 05:39 PM

Does your car makes that sssssshhh sound when it starts to create boost?

I jus got a turboxs boost controller
And overboosting has been the issue
I've been trying to get it a set level
But I have a broken blowoff valve
Which I think is causing my boost level to go ballistic
And I'm not holding boost either
I tried dialing it at 10 psi
But when it gets to 10 it drops back down
Not even holding for a second

Does anybody have a stock bov for sale for cheap?

01-05-2007, 11:39 PM	#1
abhattan 3" Exhaust Join Date: Oct 2006 Location: Brentwood, New York Posts: 162	Not Holding Boost Hello again. I need a little wisdom here. I have a '90 MK3 Turbo. The car is not holding boost. If I accellerate slowly, I get a stuttering or chattering a little above 2lbs. If driven hard, it holds boost. It almost felt like clutch chatter, but it only does it a little into boost at any RPM range. Could it be the wastegate? Stock Turbo, 142000 miles.

01-09-2007, 05:10 AM	#3
drmmr15 3" Exhaust Join Date: Jul 2006 Location: Seattle, WA Posts: 73	How do you get to that hose? __________________ 1987 Supra Turbo GReddy TT Open Element Filter (<---not sure what brand) YAY BOOST!!!!....finally...

01-10-2007, 05:39 PM	#5
Supra2NR 1000whp postwhore Join Date: Apr 2006 Location: Chi-Town Posts: 1,643	Does your car makes that sssssshhh sound when it starts to create boost? I jus got a turboxs boost controller And overboosting has been the issue I've been trying to get it a set level But I have a broken blowoff valve Which I think is causing my boost level to go ballistic And I'm not holding boost either I tried dialing it at 10 psi But when it gets to 10 it drops back down Not even holding for a second Does anybody have a stock bov for sale for cheap? __________________ http://www.myspace.com/supra_2nr Into Bikes now,, apparently the supra couldnt kill me, so my zx6 might lol

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01-06-2007, 03:02 PM	#2
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	Stock Turbo, 142000 miles. There's your problem. By the way you are describing it, it sounds like excessive shaft bearing play on that sucker. You can check it by removing the air box/MAF/accordian hose that goes onto the compressor housing (inlet) of the turbo and with your index finger and thumb try wobbling the compressor wheel shaft. The spec is something like .13 mm so any play at all is not good. Only other way you won't hold boost is a vacuum leak. Try checking the vacuum hose that runs to the wastegate actuator.

01-09-2007, 04:18 PM	#4
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	Take off the big rubber hose that goes from your MAF sensor to the compressor housing. We usually call it the accordian hose because it has ribs in it that looks like an accordian. It will be staring you in the face then.