i've had my Z for about 5 months now, and i belive i know quiet a bit about it, reason being is that i was raised up around camaros, and the "muscle cars" of sort...

any how i did i search on (FUEL PUMP) and find alot of problems similar in my case that might lead to a weak or faulty fuel pump.

any how i filled up with gas tonight, and noticed a strong smell of gas after i got home, and out of the car, i smelt around the left rear tire, and it was really strong! i then went in and got a flashlight, and noticed that gas had been leaking from my gas cap! im wondering if the gas cap is not holding pressure in the tank and thats my reason for having to cycle the key a # of times, before it starts, and then thats some how related to my high rpm "surge".

if the fuel pump is pumping or building up pressure but its going out of the gas cap.

WHAT DO YOU THINK???

thanks,
steve

 

No likely. The only reason they put a sealed cap on the fuel tank is to prevent fuel vapor emissions from the tank. The residual vapor pressure in the fuel is what builds that pressure, and it is vented through the charcoal canister in the left rear fender. That canister absorbs the hydrocarbon vapors, and holds them until you operate the engine. Under certain conditions, the EEC vacuum solenoid opens and purges the vapors into the intake manifold to be burned.

The fuel system does not rely on pressure in the tank to pressure the fuel system. The pump, the check valve in the pump, and the fuel pressure regulator take care of that.

If you smell fuel near the fill cap, it could be 1) that you overfilled the tank (not a good idea), 2) a problem with a worn out fuel pump that is overheating the fuel in the tank and causing excessive vapors and excess pressure to release the pressure relief valve in the canister system, or 3) a saturated canister (overfilling can cause this) or broken rubber vent lines from the tank to the canister.

Since you have a problem with start after the car has been sitting a while, its likely the check valve in the fuel pump has died, and the pressure in the lines is dropping too quickly. Or, maybe the pump is wearing out, and the vapor smell is a result of that problem.

Have you ever checked the fuel pressure when you shut the key off, to see how long it takes to bleed down? Have you checked the fuel pressure regulator vacuum line to see if there is any fuel in it, indicating a leaking diaphragm? Have you pulled the fuel rails up with the injectors intact, to check for dripping injectors with pressure in the system? All of those problems can make the car hard to start.

 

no i have'nt done a fuel pressure test, but i certainly need too...
anyways its not just fuems, its raw gasoline running down the filler tube, which is leaking from the gas cap!

and i kinda have a feeling its a tired fuel pump...but sure hopein its the gas cap!

thanks again,
steve