When I accelerate hard the boost will climb immediately to between 15-18 lbs of boost and then drop to 0 until I let off the throttle completely. I'm guessing that I have a bad waste gate. Is there a way for me to be sure? When truck was running right about 2 months ago it would climb right up to between 35-38 lbs. at full throttle.

Thanks

Todd

 

Are you hearing any strange air noises when this occurs?

 

Just a pop when the boost goes to 0

 

First start looking for leaks...do a make-shift plug for the intake side of the turbo and compress the system using a shop air-compressor. If your "plug" is air tight, you shouldn't lose ANY pressure...

 

is your gauge mechanical or is it plugged into the map sensor. if it is plugged into the sensor the sensor could be bad. that would also cause the truck to run back and not show any boost.

danny

 

I have a mechanical guage, there is a pop and it drops to 0 on the guage and there is no power and the EGT's start to climb very quickly. If there was a leak I would expect that the power would be reduced all the time which it isn't. That's why I didn't know anything was wrong with the truck until I punched it to the floor and it took off like normal until the boost hits about between 15-18 pounds and then boom back to 0.

 

Yeap, you have a boost leak. Probably one of the connecting hoses has a loose clamp.

 

Sounds like an intercooler boot to me. In other words ya gotta a leak

 

Leaks can work in mysterious ways...might be with enough boost whatever is "popping" releases pressure then "reseals" itself when you lose pressure...not saying that is what it is, but that's definetly where you should start.

 

04.5 year truck, do you have plastic side tanks on your inter cooler?


Tim

 

This sounds more like the waste gate is popping open.

 

No, that is on the 05' trucks only.

 

i don't think a wastgate will relieve all the pressure, it sounds like a rubber hose is popping loose at pressure and resealing when pressure drops

 

I did some more testing on the interstate. I could ease the boost up to about 30 lbs when it would pop and go to 0. It's possible that the mechanical guage doesn't respond fast enough and it's really popping at around 30 lbs. I will try to get a good look under the hood in the next couple of days.

Thanks for all your responses

Todd

 

+1 for the wastgate.