No boost past 11 psi

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Rczop2

Guest
Today I took a ride and while trying to pass someone in traffic, I noticed I couldn't boost past 11 psi. My profec B is set at 14 psi on the high and lo boost setting (which I did to make sure that its not something im setting wrong or neglecting to check) and it still wont hit the target boost. It was fine yesterday, but today somethings wrong. I dont hear any wierd noises from the engine bay, but could it possibly be the turbo going out? It's a 60-1 upgraded ct-26. All the vacuum hoses have been checked, and the connections on the profec all seem to be fine. BTW, it seems to fluctuate between 9-11 psi at times also.
 
T

thesupraman

Smirker
May 15, 2005
129
0
0
Frenchtown, NJ
Make sure something didn't fall into the turbo inlet. Low boost and boost fluctuation are signs of a chewed up compressor wheel. As Anh said, it could also be wastegate or actuator related, or the boost controller itself.
 
R

Rczop2

Guest
Thanks for the response. I have yet had the time to look at everything. I hope its not the turbo. There's only 2000 mi on it. I'll take a look at it tomorrow. My OTHER woman just came home and I MUST spend some time with her. Or so she says. ;)
 
R

Rczop2

Guest
Pink eye, I've heard that you are supposed to concoct (sp?) a tube with a nipple for a pressureized air feed and put it into the intake system some way. Then pressureize the system with an air tank or a pump. Next you either listen for leaks or with a pressure guage you will see if its losing air.
 
GrimJack

GrimJack

Administrator
Dec 31, 1969
12,377
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idriders.com
Rczop2, that's basically it.

Pick up a pipe end that fits in the end of the accordian hose, drill a hole and mount a tire pressure valve in it, then replace your AFM with this plug and tighten it down. Pressurize the system with an air compressor and listen for the whistle of leaks. Fix any that you find.

Alternatively, you can buy an inflatable plug from a plumbing supply shop. Use that to plug one end and use one of the smaller hoses into the intake to add pressure to the system.
 
R

Rczop2

Guest
Alright guys, I tightened everything down more, checked the turbo inlet for a chewed compressor wheel and shaft play, double checked the connections on the boost controller. I still have yet to figure out how to check the actuator(if its shown in the tsrm then I will see it shortly). When I took it around the block, there is no fluctuation with psi levels, it just boosts to 11 psi and wont go any further. The boost comes on strong when I first try it, but after a couple of minutes when the clutch warms up, it starts to lag somewhat, and seems to struggle to get to 11 psi. Is it possible that I have clutch slippage and its causing me not to make any more boost. It's an RPS sport clutch and its mated to a fidanza lightweight flywheel. Im going to pressure test the intake system tomorrow to see if that is still a possibility. :dunno:
 
R

Rczop2

Guest
Mr Y,

Will I be able to check for this without pulling the turbo apart?
 
GrimJack

GrimJack

Administrator
Dec 31, 1969
12,377
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Richmond, BC, Canada
idriders.com
No, to check that you need to pull the turbo. It would take an awfully big crack in there to stop you from boosing over 11psi. Try the washer shim stunt, that will tell you if you have a tired wastegate spring. (The manual requires a vacuum pump to check the actuator :()

To check the clutch, see if you can get higher boost in the lower gears - you clutch will slip in 5th worse than it slips in, say, 3rd. Normally you will be able to hold more boost in the later gears as well. So, if you can boost to 11 in 3rd and 5th only allows you to boost to 9 or 10, your clutch is a part of the problem.

I assume you pulled the coupler from the 3000 pipe to the throttle body off and checked it? If not... do that.
 
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