Fuel pump

I think I'm having fuel pump issues. Car seems to work fine up through 2nd gear, then starts to sputter and hesitate after a few seconds of accceleration. Seems like it is starved for fuel, like once the carb uses up the gas that's in there, the pump can't keep up with demand.

If I coast for a while, then that pattern starts over.... OK for a few seconds, then sputter, but only under a load... It coasts and idles just fine.

A couple questions... Is there a way to test my theory?

If my pump is bad, any suggestions on replacement? aftermarket mechanical pump, or should I consider an electric fuel pump instead?

I think I'm having fuel pump issues. Car seems to work fine up through 2nd gear, then starts to sputter and hesitate after a few seconds of accceleration. Seems like it is starved for fuel, like once the carb uses up the gas that's in there, the pump can't keep up with demand.

If I coast for a while, then that pattern starts over.... OK for a few seconds, then sputter, but only under a load... It coasts and idles just fine.

A couple questions... Is there a way to test my theory?

If my pump is bad, any suggestions on replacement? aftermarket mechanical pump, or should I consider an electric fuel pump instead?

Click to expand...

You can check it with a vacuum gage. The gage I have says it should be between 7-10" of vacuum. Just disconnect the fuel inlet to the pump and connect the gage and start the car.

Thanks for the advice.

Any thoughts on disconnecting the fuel line at the carb, and see if it pumps good while turning over the engine with the starter? Other than the obvious flamability concern.

There is a filter "sock" on the pick up tube inside the gas tank. Sender has to come out to check it. If it has been in there since the 70's chances are its clogged or has a layer of varnish.

Make sure to have the least amount of fuel in the tank before removal.

Steel lines can also get clogged with rust build up inside, blow out with compressed air carefully. Leftover fuel will spray everywhere.

just some ideas to check.

Thanks for the advice.

Any thoughts on disconnecting the fuel line at the carb, and see if it pumps good while turning over the engine with the starter? Other than the obvious flamability concern.

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Besides the safety issue it will pump fluid as the car is getting gas at idle or low speeds now. The unknown is how well it's pumping. If its a real old pump it may be worth just changing it out or going with an electric one. Vacuum gauges are relatively inexpensive so it may be worth getting one if you don't have one now. They are a good diagnostic tool when trouble shooting timing issues too.

If you disconnect it at the carburetor make sure you have a long enough hose to be able to get it to a good container. Disconnect the coil + wire so you don't generate unwanted sparks. Crank the engine over, it should pump a pint in 15 to 20 seconds.

sounds like a failing pump. look here http://www.aa1car.com/library/fuel_pump_mechanical.htm

Thanks for all the great advice!!!

I bit the bullet years ago and bought a "quiet" carter gold....

No regulator needed ... Keeps about 6 pound pressure (have gauge) even at very high rev...

Never had a problem since...

I, like many others don't drive the old horse regularly, so it used to be a pain cranking over to get fuel to the bowls after weeks or months of sitting...

Now, I just wait 20 seconds, 2 pumps of the pedal and it always starts first time....

A good replacement mechanical pump should work fine for all but fairly serious hardware.

We've seen a rash of deteriorated rubber lines restricting fuel flow the last couple of years, Ethanol is no friend to them.

Drive down the road and give it throttle until it dies. Cut it off and coast to a stop. Pull the top of the carb to check fuel level. You will know for sure which direction to go in. I had a truck do this, tried all those normal trouble shooting things. Turns out that rubber trash in the bowl was blocking the jets. If would float out of the ports after resting. If you have no fuel, the other items mentioned are very reasonable reasons for failure.

More excellent advice!

I bit the bullet years ago and bought a "quiet" carter gold....

No regulator needed ... Keeps about 6 pound pressure (have gauge) even at very high rev...

Never had a problem since...

I, like many others don't drive the old horse regularly, so it used to be a pain cranking over to get fuel to the bowls after weeks or months of sitting...

Now, I just wait 20 seconds, 2 pumps of the pedal and it always starts first time....

Click to expand...

Hey JimNiki... Is this the fuel pump you're talking about?

http://www.jegs.com/i/Carter/180/M6882/10002/-1

I'm having similar issues, it doesn't happen very often now but I don't want to wait until it really gets bad. Its not a lot of money and it seems like an easy weekend projects. Please let me know... Thanks!

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Sorry bud, mine's electric. Even the best mechanical pumps won't stop your bowls from draining eventually.

If you will be driving regularly, then not a problem...

Sorry bud, mine's electric. Even the best mechanical pumps won't stop your bowls from draining eventually.

If you will be driving regularly, then not a problem...

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Thanks... If I'm lucky I drive it twice a week. I think a carb rebuild would also help.

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start simple...

1. Do you have a fuel filter that could be restricted?

2. Is the float sticking?

3. Is there a delivery line pinched or collapsed?

4. Is the pump pumping?

5. Is there unrestricted flow from the tank?

... now break out the big boy tools if you have too.

start simple...

1. Do you have a fuel filter that could be restricted?

2. Is the float sticking?

3. Is there a delivery line pinched or collapsed?

4. Is the pump pumping?

5. Is there unrestricted flow from the tank?

... now break out the big boy tools if you have too.

Click to expand...

Thanks... all sounds like great advise. I changed the fuel filter the last time I had some hesitation that seemed to cure the problem. That was about 6 months ago. Just recently started again so I changed the filter and all seems well. How would I check to see if the float is sticking? I don't see any leaks except for a small power steering fluid leak. Thanks again...

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It's definitely the fuel pump... I tried to start the engine, but it just cranked and cranked. So I put about 2-3 ounces of fuel into the carb and it fired right up, only to stall again after a few seconds. Another few ounces down the carb, and this time it stayed on, and idled fine.

So it took the faster actuation caused by idle speed of the lever on the pump in order to pump enough gas.

I revved uo to 2,500 and within a few seconds, it sputtered.

No bad lines that I could see, and the filter looked clean.

I'm too damn big to get under the car without jacking it up, so looks like I need to borrow my buddies jack and stands...

What is a good thing to use to stop up the fuel lines when disconnected from the pump?

My water pump is making noise... Should I replace that at the same time?

Throw a couple of bags of these in the bottom of your tool box and you'll be forever grateful...