Fuel Pump Issues?

[momoparman]

I am looking for some input on what I think is a fuel related problem before I tear into my car.

Engine is a 383 with a mechanical Carter fuel pump.

The pump is about 8-10 yrs old and does not leak.

Problem is the engine is stumbling at low RPM's like its running out of gas.

If I pump the gas pedal many times is sputters and starts idling normally. When I am driving under normal conditions it seems to be OK.

At low RPM when you give it gas it will backfire through the carb as well.

I noticed bubbles in the clear fuel filter and it seems like the filter is not filling up all the way. I am suspecting a bad fuel pump but do not have a pressure gauge to determine if this is the case.

Am I on the right track (Bad Fuel Pump) or do I need to spend the $$ to buy a pressure gauge to test the theory first.

I have a lot of experience with electric pumps but not much with mechanical pumps so I am not sure what to look for besides what I have mentioned above.

Help appreciated.

Thanks,

Mop

 

[wirenut]

how is it under WOT or under load?
Do you have the distributor vac advance connected?
Is the timing set correctly?
Is the idle adjustment so high that the carb is no longer on the idle circuit?
is it a old worn carb or ?

 

[momoparman]

Everything is OK on this car.

It has run great for 5 years.

UNDER WOT now it runs OK for a few then it coughs and back fires. till I let off the gas.....if I wait a second then drive at normal highway speed it smooths out then its OK......until I come to a stop and sith there at idle for a few.

Under light pedal from stop it coughs and sputters and back fires through the carb like its real lean.

I have to pump the gas pedal at stop as while I sit there it starts to starve out.....Once I pump the pedal and get it going down the road under normal driving speeds its OK.

Like I said it seems like a fuel problem.
Newer carb edelbrock...2006.
Newer dist....Mopar Perf Electronic ...2006
Vac adv hooked up and working.
Idles at 900-1000 real smooth


Mop

 

[river rat]

Might be the sending unit. If its original, thats a quick and fairly cheap replacement.

 

[RedFish]

That problem is in the carb not the fuel pump. The bubble in the fuel filter is normal. You can relocate the fuel to a vertical position behind the altenater and get the bubble out or buy a metal filter so you can't see the bubble. LOL
GM quadrojet carbs had the same symptom. Their venturi bleed tubes would drop out from where they were sataked into the casting. Slow throttle open was fine but quick throttle open caused hesitation and backfire. Hope this helps.