Fuel pump woes

[RayW]

Just thought I’d share my recent fuel pump woes in case it could help anyone. I recently had to replace two old failing fuel pumps— one on my 73 Commando 304 and one on my 70 Wagoneer 350 Buick. First, I ordered a Delphi fuel pump for the 304. After start up, engine sounded like it had a horrific valve tap. It was the fuel pump— rocker arm just rattled up and down. Ordered a Carter. Installed the Carter only to find the outlet fitting barely threaded, not even enough threads to tighten the flare nut. Received replacement Carter. Ran fine for a minute, then started idling roughly with fuel coming out of the MC 2100 vents (rebuilt carb BTW). Put my vacuum/fuel pressure gauge on the pump and 10 lbs of pressure (maxed out the gauge). Returned the Carter and ordered a Crown. Same thing— flooding, etc. Fuel pressure gauge again was pegged at 10 psi. Tried a regulator, but with no place for the excess fuel to go, gas just leaked out around the fuel pump bowl where it was crimped to the body of the pump. Fortunately Carl Walck had an old nos Carter pump from probably the 80’s made in Canada. Installed the old Carter and it runs beautifully. 4.5 lbs of pressure from the pump, smooth idle, no flooding or running rich— car’s been running great. Now for the Wagoneer. New Carter pump, same rough idle, flooding, etc. This Carter is putting out 9 lbs of pressure. TSM calls for no more than 5.5 lbs. The Wagoneer fuel pump has a return, so installing a regulator set to 5.5 lbs has been working fine and the Wagoneer has been running great. That’s 5 new pumps, and not one performing to the application’s OE specs. Are there any good, new fuel pumps out there?

[tgreese]

IME what NAPA sells is higher quality and more expensive than the generic brands. They buy and relabel their parts, thus you don't know who their supplier is. Their fuel pumps used to be Airtex (presumably) but who knows who their supplier is now.

For the Buick, you might call TA Performance and ask. Or check the Buick forums.

[devildog80]

Thanks for sharing your fuel pump experience. Always good to have more reference notes to troubleshoot.

[letank]

one reason to go electric, get another spare , easy swap when needed.

[Harry Dawg]

I actually had a fuel pump mishap this morning.

Sitting at a red light, and my oil pressure starts to drop to around 40 PSI (usually I have 60 at idle)

I thought maybe because it was hot, but I pulled into work and popped the hood... oil all over the engine bay.

Seems like the diaphragm has failed and is leaking oil out of the weep hole : (

The mechanical pumps for the 327 are no longer offered AFAIK, so I am just going to install a block off plate and run an electric pump.

I also have a tapping noise (even after going through the entire valve train) so that would be awesome if deleting the mechanical pump solves this.

EDIT - I just rebuilt this pump, and it's got less than a 100 miles on it. Additionally, because the mech. pump sits above the exhaust cross over on the 327, I think an electric pump will be a good safety upgrade.

[Yeller]

today's mechanical pumps are horrible. Everyone I know running one carries at least one in the truck. I carry a spare electric.

[Stuka]

Parts quality as a whole has gone downhill over the last 10-15 years. There are still good parts out there, but they certainly cost more.

Having your oil sump fill up with gasoline because of a failed diaphragm is never the start of a good day.