VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Aftermarket OEM fuel pump pressures.

Just wanted to share a frustrating issue I've noticed with oem stock replacement fuel pumps for SBC's.

The carb on my stock '76 350 Impala was/is leaking down internally after a hot shut off.It's a QJet,so I rebuilt it going through it carefully addressing all the nuances they are know for.

Throw it back on the car,adjust,runs great.I heat cycle the engine shut it off check next morning and I have raw fuel in intake plenum.

So I checked both cranking and running fuel pressures and was shocked at the high readings I got.I had 10.5 psi coming into the carb! Ideally it should be 5 maybe 6psi.

So I did some research and tried to hunt down fuel pressure ratings for all the various years of SBC '65-'85 replacements currently on the market.I bought up 5 of the various brands,including Delco.NONE of them when tested pumped close to the correct pressure needed to make the Q-Jet happy!And NONE of them met their listed pph rating!!All pump at btw 7-11psi! WTF?? Everyone of the stock replacement pumps are made off shore.I think this is a big problem.

I really want to keep the stock look,and I am gettin' pissed off because I don't want to put on a chrome perf pump or run a adjustable fuel pressure regulator. Anyone else experience this? Jim

Long story short.....excessive fuel pump pressure is forcing the float needle off of the seat pushing fuel past it after hot shut off.
Crappy import junk parts today suck! I'd gladly pay double for an accurate,US made, pph/psi fuel pump!

Did you seal the bottom bowl plugs with epoxy? They often leaked down on a Quadrajet.

Of course Gene.Not only the 2 large plugs but also the 4 small under the primary.It's definitely a fuel pressure issue.Float,needle and seat are over whelmed.