Speed Demon

i have an 86' 951...


i'm trying to figure out what is wrong with my car...

when i accelerate the car in gear, i get no "pull" from the turbo...

the boost gauge seems to be reading normally but i get no "pull"...

All i hear is a loud hissing sound coming in from the front of the car...

I clamped off the line from the cycling valve to the wastegate...and i got the same result...

So i was thinking that the turbo pressure isn't going to the wastegate...

ANY IDEAS???

if anyone is in the area... and would like to help... i'll be willing to make up for your time...

I'm in Plainfield, IL

Thanks,

I really hope to get this solved soon

skene

bad BOV maybe?

formerGMguy

I was thinking the same thing, but I doubt thats it. A bad bypass valve would allow air to "circulate" through the intake system with a loss of boost. I'm not certain however if the bypass valve can flow enough air to stop the car from building boost at any noticable level. Plus if the valve was blown you'd expect the car to run poorly at idle since it would essentially be a vacuum leak.

You could always remove it and check to see if the diaphragm is intact or not, its only a five minute job, and you'll know if its dead.

Bri Bro

Check all the rubber/clamp connections on the IC pipes. The cracks can be hard to locate.

Speed Demon

I took off the BOV and there is no damage to the diaphram...

all the IC pipes are really tight..

here is a pic....

I could have missed something....




thanks

Bri Bro

They may have a split in the rubber boots that will be hard to find without preasure testing or removing the part. I had a wear point on the IC and it caused a pinhole leak under the pipe. That metal is very thin.

Speed Demon

i'll add this again maybe the sound effects may help....

when in gear and i floor it i hear a "shhhh"

I shift and i hear a "woosh"

almost as if my car were really modified but it's not

nine-44

Call around and see if a shop can do a leak test with a "smoke" machine. Basicly they hook up a tank of CO2 or Nitrogen, I forget. Anywho, where ever the leak is will smoke.

Try to test your bypass valve with a vaccume tester, see if it bleeds down or holds vaccume.

JasonKaw

Well, it sounds like we have a simaler problom, I brought my car to the shop, I will not find the problem out untill early to mid this week, for other suggestions check out my forum called "Power Loss" if you find out your issue before mine, please let me know, and I will do the same. I also replaced the BOV and that did not seem to be the issue on my side either. I will keep you poster!!

JasonKaw

Posted!!

94489T

what is that switch all the way to the rigt near radiator fill tank?

Speed Demon

that switch is some sensor i guess..

i got it after i installed a remote start on the car...

i think so that you can't turn on the car with the hood open