Camaroguy91

my camaro will only start when its cold and when i do so i have to do a couple cranks to get it started but when its been driven and is hot and i shut the car off it will not start for nothing until it sits for awhile. ive changed the fuel filter, the ignition coil module, oil change, tune up, (theyve all been done by a shop not by me) ive added premium fuel to burn off the "gunk", added fuel injector cleaner, and moisture remover to my tank. this car has many mechanics bewildered i should say. i dont know what else to try, i really need help. another thing i should mention when i take off the gas cap it always blows out air. when the cars been on it will let out hot air always it could have a full tank of gas and it still does it. any help greatly appreciated.

skibum2100

Your injectors may be on the way out. They could be making the mixture so rich it won't run except when cold. Start off by ohm-checking them (they should all be around the same value, ~16). Then put a fuel pressure gauge on and note how fast the fuel pressure drops after you stop the engine. If it immediately drops to <10 psi, your injectors may be leaking. You could pull your spark plugs and see if they are fuel soaked. Also pull the vacuum hose to the fuel pressure regulator, and smell for fuel on the inside of the hose (to indicate a torn regulator diaphragm).

The fuel tank will hold 1.0 psi of pressure before the release valve kicks in, and 1.0 psi "feels" like alot when you pop the fuel cap and the pressure bleeds off for 20 seconds. But its okay.

Hope this helps.

87rattler

When you try to start it hot, does it even crank? If not, do you have headers? If so, the starter sits really close to the hot headers and may be getting too hot while the car is running. Once it has cooled down, it will crank. Seems to be a somewhat common problem.