Hey all, I recently installed a new fuel pump into my 76 L48 (auto) and the first time I took the car out after installation, the car started fine, took it a mile to the gas station and as I pulled in the engine cut out and had to coast in to the spot, filled the car up and it refused to start unless my foot was planted to the floor. Got the car home and prevented it from cutting out again but had to put it in neutral and keep the revs up to prevent it from cutting out at lights. Was told by a relative that it needed the idle speed adjusted, I adjusted the speed, and the car started right up. It kept running in gear and in park with no issues, but revs were 400rpm high of what they should be ( they were 2000 cold start, 1000 in D) so I shut the car off to adjust the throttle to bring the speed down a bit, restarted the car and in park the car ran fine, put it in gear and the revs dropped to 700 for about 15-20 seconds, then dropped to 300-400 rpm before dying completely on me. When I tried to restart it I ran into the same issue of not starting unless my foot was to the floor. Anyone have similar issues? I was told this could be anything from a vacuum leak to my mixture being off. Before the new fuel pump was installed I only had the engine cut out once about 5-6 months ago, other than that nothing. Any help would be appreciated! Thanks!

 

Did you re-use the "S" hose with the new pump?

What kind of carb / fuel filter?

Fuel bowl empty when issues arise?

 

first when no start is there gas in carb by watching for squirts from accelerator pump. Should get at least several full shots..
also why did you change pump?

mine was similar
https://www.corvetteforum.com/forums...e-on-road.html

 

The seal between the top half and bottom half of the fuel pump was bad and leaking fuel.

 

Did you check the carburetor fuel filter to see if you dislodged stuff in the fuel line when you changed the pump?
What manufacturer and part number pump did you use?

 

Yes used the hoses there as I didn't see any leaks/cracks from them, and the carb is the original Rochester M4MC. When I started the car last, the fuel bowl did have some fuel in it, maybe 1/3 full.

 

Used a Delphi pump (AMF0026) and haven't checked the filter, what should I be looking for?

 

A dirty fuel filter, should be obvious when you remove it.

 

Disconnect the fuel line- put it in a container- make sure your wife /girlfriend /mom never wants to use it again- just sayin!!!

Have somebody turn the engine over and see if you get nice strong spurts of fuel. Could be a bad pump out of the box.

I had one that the spring was broken- and giving similar problems.

The fuel filter is also suspect as another poster noted.

Richard

 

One thing I would think about with China parts etc is pump no good right out of the box. It does happen.....

 

Thanks for the help guys, sorry if I'm asking some stupid questions but totally new to wrenching on the car to be honest. Quick update, got the car running just to see what happened, and ran for 10 minutes without any issue in the garage both in park and in gear, still revving about 300 rpm high though. Took it for a lap around the neighborhood to see if the car fixed itself or not and I got about half a mile before the car cut out as I was coasting to a stop. Back to square one I guess! Once the car cools down I'll pull the fuel filter out and check that out.

 

Yep- it used to be that I would question everything but the brand new part I just replaced. Now that's the first thing I check!!!

 

That's my fear, went with a summit racing pump initially, but didn't fit, so tried getting an OE one and couldn't find it anywhere around my area so went with that Delphi.

 

you are given good advice..especially the measuring flow and pressure..when checking filter run hose from fuel line to container and measure ounces in 30 seconds.

again
https://www.corvetteforum.com/forums...e-on-road.html

 

If the fuel tank does not have a vent on it, you can develop 'negative' pressure in the tank during continued use. If your car still has the fuel vapor canister system and it is working, IT will serve as the tank vent. But, if you have removed or de-commissioned it, you will need to put a vented gas cap on the tank to prevent this problem. Just another item to check if you are having fuel "flow" issues.

And, I agree that if the "S" hose between the fuel supply metal line and the fuel pump has been replaced with 'standard' fuel hose, you will most definitely have fuel a flow issue. It needs the molded fuel line so that it will not get kinked and reduce flow to barely a trickle.

 

Sounds to me like it's flooding from your description of having to hold the throttle to the floor to get it started.
The new pump may provide more pressure than the old pump and/or more than the q-jet can handle
Then it's forcing fuel past the inlet valve/jet despite the float trying to close it, flooding the motor.

Fuel starvation should require pumping of the throttle pedal NOT holding it down and cranking.

 

Did you accidently leave the previous gasket on the engine when replacing the pump so now you have two of them ? Maybe the pump arm is barely catching now...

Richard

 

This is a "fuel starvation" issue. (Post 6) The bowls will not fill. But why?

Nothing that a glass jar at the end of the gas line won't show. You will need a helper. While holding the jar at the disconnected gas line, have someone crank on it until you yell stop!

Or you may yell, WTH !

 

The bowl may only be about 1/3 full once you pull the float out. I'm not convinced its fuel starvation yet.

If it was starvation why is there any fuel in the bowl?

 

We still don't know if the OP installed a 'kinked' straight hose in place of the molded hose. If so, that's the OP's problem. If not....we need to hear more.