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Leaking fuel pump

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David_Doan

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So, today I spent some time trouble shooting the vibration problem that we had been discussing here, and I noticed gas dripping from the engine. I eventually figured out that it was coming from the mechanical fuel pump.

I took it apart and saw no issues, cleaned it up re-assembled and tested it. It works fine with nothing blocking the outlet. If there is any resistance to fuel flow, it starts leaking from the body BELOW the diaphragm. There's a small hole in the body that is apparently there to let fuel out in the event of a failure, so that it does not go into the engine and dilute the oil.


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I took the diaphragm out, dried it and inspected it. I can't find any holes, but somehow fuel is getting past it. i can't find a rebuild kit, I bought a Carter electric pump (P60504) to use until I can figure this out.

any words of wisdom on this strange leak?

David
 
You did good so far, i agree it is the diaphragm. Pump needs a rebuild.

You will be very pleased with the elec pump. Put a blanking plate on the manual pump mounting hole.
 
Electric pump... yes, manual pump, well maybe.
Make sure the pressure output of the Carter is correct...no more than 2-3 psi. If more than that, use an inline fuel regulator.
Scott in CA
 
I finished the fuel pump project today, everything worked out really well. Other than the everything takes twice as long as you estimate factor.

I started with making the blanking plate. I wanted to keep the old pump intact and available to be rebuilt. I don't have a machine shop, I just used my Dremel, file, and sandpaper.

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I got the Carter P60504 pump. It is rated at 2-4 PSI and crosses as OEM replacement for a lot of cars. It is actually made in the USA.

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I mounted the pump up under the trunk, just behind the axle. I need another strap to support the filter.

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I ran the power wire above the tank, just like the fuel level sender wire. There's just enough gap due to the corrugated floor of the trunk. To protect the wire, I ran it inside a piece of vacuum hose.

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The pump wire is connected the fuse block and is only "on" when the light switch is on "S" and the key is "on". When powered up you can hear it, but only until the engine is started.

When I have time, I want to put it on a relay and tie it to an oil pressure monitor.
 
Nice job. Well done.
 
The_architect said:
David, what would tying it to an oil pressure monitor do? Charlie
Click to expand...

I presume sudden complete drop in oil pressure would cut the fuel pump.
 
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