View Full Version : Dead fuel pump.?
JRSully
11-29-2009, 01:13 AM
Went out out fire up the Ol L78 and it was no go,specifically, NO FUEL to the carb (ran fine 2 weeks ago and at leasts 10 gallons of fuel in tank). 1st thought, dead fuel pump,(but they really don't go bad like that.?). Had another used pump laying around, bolted that on, still nuthin. Blew out the line to the tank and the carb, ok there. Only possible scenarios I can think of:
1. Both pumps are bad (remote at best)
2. Problem with the fuel pump shaft.?
Anbody have this issue with an L78.? Thx in advance
markjohnson
11-29-2009, 01:27 AM
Yeah, there's a possiblity that you installed the new fuel pump with the spring-loaded arm on top of the pushrod instead of the end of it. It's actually pretty easy to do by mistake. Be careful with a bad fuel pump, if that diaphragm is ripped, it can fill & dilute the engine oil with gasoline.
JRSully
11-29-2009, 01:41 AM
I thought I had that pushrod up there high enough to get the FP arm under (used the old grease trick) going to play with it again tomorrow morning.Thx
MosportGreen66
11-29-2009, 02:09 AM
Jim, do you check your fuses?
JRSully
11-29-2009, 02:45 AM
I should check the fuses, but that would not stop the mechanical flow of fuel through the line/pump/carb. The pump and carb are bone dry after repeated cranking
My L-78 has to be cranked for along time after sitting for a long time,to get gas back up in the system again.
5 minutes or more sometimes..
Have you adjusted/messed with your Holleys float to needle valve lately?
JRSully
11-29-2009, 03:07 AM
Car has run flawlessly for a while, didn't mess with anything,no need to. Last ran it 2 weeks ago, no problems at all, puzzling to say the least
Verne_Frantz
11-29-2009, 03:19 AM
Sully,
I assume it ran fine when you shut it down the last time. You've tried 2 fuel pumps and blown out the lines to the tank. Try isolating the delivery problem to the carb by removing the fuel line from the carb and crank it with a catch can to see if fuel "wants" to enter the carb. At least you'll know if it's something in the carb or in the path from the tank to the carb.
Verne http://www.yenko.net/ubbthreads/images/graemlins/wink.gif
Verne_Frantz
12-02-2009, 07:11 AM
Sully, what the heck is going on with your fuel delivery problems? http://www.yenko.net/ubbthreads/images/graemlins/hmmm.gif
njsteve
12-02-2009, 07:17 AM
Check the short sections of rubber fuel hose that connect the steel lines by the subframe, by the tank and from the steel lines to the pump inlet. I have seen some old rubber hoses delaminate/seperate internally and then collapse when suction is applied from the pump. They may look fine from the outside but could be completely blocked inside.
JRSully
12-02-2009, 03:33 PM
Fixed, pump was fine. My guess is this, all the fuel drained out of the Holley bowls and the majority of the f/p itself. When the engine stopped, did the f/p pump shaft off the cam leave the pump in an open position.? I don't know if that is even possible. I dumped some fuel into the carb, fired the motor, and that evidently created enough vacumm to get the whole system functioning normally again, no problems since, very funky, never had that happen before. Thx for the tips. SULLY
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