jayman10134

Hi, I am new to the forum and this is my first post. I recently purchased a 1987 Camaro Iroc 5.7 TPI with a 700R4 transmission sand 73000 miles. Everything on it is original. Never been modified in any way. I purchased it in february and drove it home (about 50 miles). Everything went fine. I have since changed out the tranny fluid and rear end fluid. It has always had no issue starting or anything of that sort. When I started it up to get it up off the ramps for the transmission fluid change today and out for my first real drive, I let go of holding the key to the starting position about a half second short and had to try it again and it had issues starting. I drove it about 15 miles and parked it. No issues. I took it out on the highway and about 10 minutes later i started to smell fuel. Upon getting to my destination I noticed there was fuel pouring out of the evap canister. I shut the car off and it didn't slow down. I quickly headed home. Anytime i slowed down i would leave a large puddle under my car. When i got to my house i shut the car off and it was still pouring out. I unscrewed the fuel tank cap and it released a lot of pressure/vacuum. (not sure which way the air was headed). Started it back up and drove it 1 minute, and had the same issue. Releasing the pressure from the fuel tank made it stop again.

I am thinking it may be the canister purge valve as that was the only line going into the canister that appeared to be wet with fuel. Is there any trouble shooting I can do before I just start replacing parts?

Injuneer

My Chiltons shows that the tank cap (TPI V8 engines) is supposed to be a pressure/vacuum relief vented cap. That would not allow excessive pressure to build up in the tank. Possibly the wrong tank. But - caution - I do not have direct experience with a 3rd Gen (my 4th Gen requires a non-vented cap) and I can only go by what is shown in Chiltons. They are not always right. An auto parts store should be able to tell you whether it takes a vented or non-vented cap.

And, obviously the pressure at which the cap relieves has to be higher than the pressure control valve (in the line from the tank to the canister) or the system would not contain emissions.

Might also want to check to see if something is causing the fuel to overheat. A failing fuel pump could cause problems, or a fuel return line too close to the exhaust. Heat causes the fuel to vaporize and the pressure builds. But there should not be any fuel at the top of the tank where the canister vent line comes off. Fuel could only reach that line if the tank was overfilled, or the fuel was boiling. Did you hear any rumbling in the tank, possibly indicating boiling?

Then there's the question of why the only line that was wet with fuel was the line from the purge solenoid to the throttle body. Where would the fuel come from if it wasn't in the line from the tank?

Hopefully there's something useful in these comments. Unfortunately, not as many 3rd Gen owners here as there used to be.