theshackle

I have a small block 350 crate motor (stock heads, compression, bottom end, etc.) with an Edlebrock perfromer series carb in my 87 Firebird Formula. The engine is very difficult to start. When I crack the fuel lines at the carb, the line is dry, even when I crack it shortly after running.

The engine has a relatively new 3 line, mechanical fuel pump. The engine runs fine once started, but is very difficult to get started, especially when hot. I don't know how to tell if the fuel is draining back through the pump, if there is a vacuum forming in the tank, or if it's something else.

I didn't do the engine swap myself. I believe the car came with EFI, so I'm concerned something was botched in the tank when the it was converted to running off a mechanical pump. Someone suggested that sediment in the tank may be preventing the anti-drainback in the pump from functioning, could this be it?

Does anyone have advice on how I can diagnose, and fix this problem?

sofakingdom

iTrader: (1)

If you shoot an ounce or 3 of fuel into the intake before trying to start it, does it start RIGHT UP?

theshackle

I haven't been able to straight dtraight fuel, it will start with starter fuel but it sputters a little bit before coming up to idle speed.

mustangman65_79

Even if the fuel was draining back through the pump, there is still fuel in the carb.

It sounds to me that the carb is slowly draining out the fuel in the bowl into the motor. Meaning now you have nothing to try and start the motor with . I hear this is a common problem with edelbrock carbs.

NoEmissions84TA

iTrader: (1)

NO, NO, NO, WRONG. This was a TPI car converted to carb. Most likely whoever converted it also got rid of the charcoal canister and fuel tank purge valves, and blocked them off. Therefore what is happening is that a vacuum is being created in the tank while running, and no air can get in. Then when the engine is turned off, the vacuum in the tank sucks the fuel out of the line and back into the tank. Vent the fuel tank and all should be fine.

You can test this for yourself by removing the gas cap after running for a while. If you hear air being pulled into the filler neck as the cap is removed, then this is your problem.