Jump to content

Fourth Fuel Pump....


Graham Man

Recommended Posts

Ok this is one of my new cars, well actually a 1977 Ford truck.  It has a 400 CID carbureted 2 barrel engine with a mechanical fuel pump.  It gets driven weekly but normally only short trips.  It ate a fuel pump a couple years ago, so I replaced it, about a year ago I lost another one, this spring I am on number two, so 4 in total.  I had a clear fuel filter in line before the carburetor, no evidence of any garbage, pulled the carburetor fuel filter, spotless, pulled the fuel sender to look in the tank, looks clean.  Last time I replace all the rubber lines.  I did not blow the lines backwards, that is next on the list, all 3/8 inch lines, in cab fuel tank, it could almost be a gravity system.  At first I blamed it on old shelf stock fuel pumps.  If I put on a new pump, it fires right up.  I only use nonalcohol fuel, and yes the gas cap is vented.

 

It has to be garbage in the tank pick up?

 

Looking for any ideas?  Last resort is put in a electric fuel pump? (I hate electric pumps)

Link to comment
Share on other sites

Any smell of fuel in the engine oil? Sometimes with mechanical fuel pumps you can smell the fuel in the oil.

 

Also do you have any of the old pumps?  What is the brand you are buying? If you have an old one, you might want to take one apart to see exactly what the failure is.  Is it the diaphragm or one of the valves?  That may help you diagnose the root problem.

 

Just some thoughts.

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

11 minutes ago, Graham Man said:

Must be a ruptured diaphragm, just stops pumping.

This usually puts gasoline into the crankcase. Not what you seem to have. Loose check valves stops pumping without leaking fuel anywhere (internal or external). I know loose check valves are an issue on new Corvair fuel pumps (for several years now). Lucky, those are screwed together, so one can open them up, re-stake the valves, and continue using them. All the pumps assembled with crimp edged are hard to open and even harder to reassemble!😲

Link to comment
Share on other sites

10 hours ago, Graham Man said:

Must be a ruptured diaphragm, just stops pumping.  No fuel leakage, no noise, lever looks new.  If I put a new one in the truck fires right up.

 

Could be bad check valves at the inlet/outlet ports. Could be trash in the tank or lines that holds these valves open. Take a failed pump, hold it in a bench vice, and actuate the lever to see if you get any suction. Consider an inline fuel filter on the INLET side of the pump.

  • Thanks 1
Link to comment
Share on other sites

Sounds like a restriction on the supply side where a new pump will overcome it but it causes early failure in the pump.  I'd replace the tank and lines.  You say the 'tank looks clean' without conviction, I read a little doubt into it.

Link to comment
Share on other sites

  • 4 weeks later...

Yes all good fuel pumps, factory style mechanical pump, replaced all the rubber lines.  This last time again with a new fuel pump I blew the line backwards with compressed air.  My only guess is small sediment plugging the factory fuel pick up sock?  Running good again, we will see how long this one lasts...

Link to comment
Share on other sites

Just curious. Could it be Ethanol that's causing the problem ?   I put on a new old stock ( really old ) fuel pump on my '35 which lasted about 100 miles.  Replaced the fuel pump diaphragm with one made from Nitrile which is supposed to work with the ethanol in the gas.

Link to comment
Share on other sites

6 hours ago, Billy J said:

Just curious. Could it be Ethanol that's causing the problem ?   I put on a new old stock ( really old ) fuel pump on my '35 which lasted about 100 miles.  Replaced the fuel pump diaphragm with one made from Nitrile which is supposed to work with the ethanol in the gas.

 

NOS pumps will likely not be ethanol compatible.

Link to comment
Share on other sites

I have not put alcohol fuel in any of my carbureted cars for about 6 years, it is wonderful, don't have to rebuild carburetors every spring anymore.  You are correct incorrect fuel pump diaphragm dies quickly.

 

I use this kit for most of my pre-war cars work great in all early Graham-Paige cars

 

https://store.fillingstation.com/detail/FS-908/Chevrolet_192933_FUEL_PUMP_REPAIR_KIT.html

 

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...