[03 Z71 5.3]

Hey lads my buddy has an 03 GTP, he has only had it for a couple of weeks everything has been working great with the car, this past friday we went to Ottawa and notice he make at the most was 2 pounds of boost when passing cars, I dont no the proper name but could there be a vavle on the supercharger that is stuck open and all the boost is going out the by-pass vavle???? just a hunch yea the engine light is on but does not flash the prev- owner said he did have it tested and it was the fuel cap ???

 

[MrCritical]

He didn't have a fuel cap replaced on a nice car? Bull.

Find out from a qualified source what the code is for the warning light.

 

[dav305z]

Yeah, your best bet is to have it really checked out, because it could be a number of things. A few quick items you can check are the air filter and the serpentine belt. The supercharger is only going to boost as much air as gets to the engine, so if your air filter is dirty that could be partially responsible. The belt is supposed to get replaced after 70k or thereabouts.

That said, neither of those would be the real source of the problem, IMO. If they were, you would notice other symptoms. What sort of fuel economy is it getting? Is it making any grinding noises?

There is one valve that can be adjusted, although I don't know its exact name. It's on top of the S/C (the unit itself, not the snout) and basically it controls how much throttle pressure it takes to generate boost.

One last bit of advice is to try clubgp.com. Those guys really know every single thing about our cars.

 

[tholland]

There is one valve that can be adjusted, although I don't know its exact name. It's on top of the S/C (the unit itself, not the snout) and basically it controls how much throttle pressure it takes to generate boost.

Yes, very likely it's the boost bypass valve (BBV) which is bolted to the front right side of the supercharger viewed from the front of the car. A common problem is the selenoid bolted to the valve itself which can be replaced separately.

 

[03 Z71 5.3]

Thanks for the infor guy's I'll keep up to date on what is going on with his car I told him to take it to the shop we will see what he does!!!!

 

[jfnz24]

One thing that wasn't mentioned is that the boost might not be working solely become the CEC light is on. I know in my car, if the CEC light comes on, it disables some "non-essential" items. This may be the same case here, which would need further diagnosis for what is causing the CEC light to come on.