help needed on efi'd '79 425 caddy - non high perf related

[dave_brode]

Hello All,
Car will run if gas is poured into TB, but not run real well. Elec pump will run for a few seconds when key is turned to run. Very little fuel leaks from schrader valve after pump is made to run. No fuel exits regulator when pump is made to run, or when cranking engine. Very little fuel exits engine mounted filter, while cranking engine, with fuel line removed.

Tank and elec pump are new. Are there back yard checks that I can do? TIA for any help.
Dave

[curtis73]

Whenever that happens to me I pull the fuel line off at various places and blow backwards through it. Sometimes a flake of rust, dirt, or for that matter an accidental shard of metal from the manufacturing process makes its way somewhere it shouldn't.

Are the lines new? You might find one section has a lot of resistance when you blow through it, and if so you might have rust inside a hard line.

Did you test the voltage to the pump? Ground from the pump? Put a voltmeter between the ground post on the pump (or the post on the sending unit for ground) and a ground on the frame. Run the pump and if you get more than 0.1v, you should re-ground the pump.

I would also test the fuel pressure both at the engine and by pulling the hose near the tank. If there is more pressure at the back, its a line thing. If there isn't, its a faulty pump.

[PeteR]

Or maybe the engine mounted fuel filter is clogged?

If it's the standard pump, it has a capacity of 2 liters/min so
plenty of fuel shold exit the regulator at all times.

[dave_brode]

Curtis and Pete,

Thanks much. I'll check it out.
Dave

[Michael F]

Dave
I had the same situation in a 85 Corvette that had been sitting for at least ten years. We removed the tank, put new pump and filter and the car started fine, then was stored again. Two years later we found out that the new filter was clogged again and had to be replaced. I wonder the 95/98 grade we have over here have :?: some specific additives in it which do not remain stable. My 2 cents. MF

[dave_brode]

Hi Michael,

Thanks. The filter is clean. It has a new tank and intank pump. Both pumps are running. I suspect that it's either the new pump isn't working, or the frame mounted pump is bad, or clogged with trash from the old tank. Will check it out.
Dave


F"]Dave
I had the same situation in a 85 Corvette that had been sitting for at least ten years. We removed the tank, put new pump and filter and the car started fine, then was stored again. Two years later we found out that the new filter was clogged again and had to be replaced. I wonder the 95/98 grade we have over here have :?: some specific additives in it which do not remain stable. My 2 cents. MF[/quote]