I know this forum is suppose to be only for Camaros but I have a driveability problem with a 95 Tahoe with the 5.7 TBI which I think is similar with some Camaros. A co-worker came to me with his truck dumping white smoke out the tailpipe and couldn't idle under 2K rpm. At first seeing the white smoke from the exhaust, I assumed it was a head gasket but compression is 135-143 between all eight cylinders. There's no water in the oil nor any overheating or loss of coolant. Just alot of white smoke out the exhaust. I noticed that the smell of the white smoke was more like excessive fuel rather than steam from coolant. But I always thought that an overly rich mixture created black smoke? When I inspected the spark plugs all were wet and black. I replaced the O2 sensor thinking that was the problem but it wasn't, I then removed and inspected the fuel regulator diaphram located at the top of the TBI but found no visible cracks,tears, or leaks. There are no check engine light displayed. I'm stumped, any suggestions are greatly appreciated.

 

Have you checked the fuel pressure and regulator function with a pressure gage? You could conceivably get white smoke if you are running exteremely rich, to the point where the fuel never gets lit up and the vapor just dumped out of the exhaust, but I never saw it happen except in very large diesel engines and gas turbines.

 

You're sure it's white and not a light blueish gray? What you're describing sounds an awful lot like excessive oil consumption, too....

 

It kind of does look kinda light gray or blue but mostly white. You may be right but we haven't had the chance to run it long enough to see any type of oil consumtion. This happen so sudden like running well one day then smoking on the next. The reason I'm guessing fuel is because of the smell. I know what oil burning smells like because my 88 camaro 2.8 reminds me every morning, but this one has more of an eye burning smell. And the plugs aren't really oil fouled but more like wet then it dries out after several minutes when left out. I'm gonna try a leak test #1 cylinder and see what happens and while I'm at it I'll pop off the valve spring to check the valve seal. Do you think maybe all of the oil control rings gave up, or maybe valve seals. I don't have any excessive blow by. Thanks for the replies.

 

I would think that if there's that much fuel getting into the engine, you'd be getting into hydrolock territory there. I could be wrong, but it seems a bit excessive. I'd run an alcohol contamination and fuel pressure/volume tests.

 

What is an alcohol contamination and fuel pressure/volume tests? Can I do this myself using supplies from the local parts stores or do I have to bring this to a shop. You mention hydrolock, I'm wondering if that's why when I try to accelerate quickly it has a slight knocking sound? Thanks.

 

You can, and I'll explain it sometime tonight, I've gotta run right now, but you'll need a fuel pressure gauge that'll hook on to the fuel lines in that car, a clean glass bottle at least one pint in volume, and a 100 ml graduated cylender.

 

Does anyone know if the aftermarket suppliers have an inexpensive kit to test how much fuel is in your motor oil?

 

Yeah, 7 Eleven. Get a lighter and hold it to the dipstick (away from the car, of course.) If it lights, you've got too much gas in the oil.

Edit:

Yes, I really am serious about that. Just don't hold it too close to your body.

 

Believe it or not Flufy-T I actually did this and it didn't FLAME ON. Did you ever get the chance to check on the "alcohol contamination and fuel pressure/volume tests? Thanks