Fuel pressure builds after a short while Options

[Seabird]

Hello all!

Having some on going difficulties with my fuel system. Last time at the track I had a lean running condition when under load on the 1-2 bank. Swapped a gasket once back home and now can't replicate the problem.

Decided I was going to refresh a few components as a precautionary measure. Fuel regulator (as this is where the split happens between the left and right carbs), fuel pressure gauge (the old one was well old), and adding a spare carb to my track side spares.

Previously I had not had a problem with fuel pressure per the gauge. After swapping in a fresh Holley 12-804 and an oil filled gauge I was unable to regulate the pressure down to 3 psi. Was not able to regulated it lower than 15 psi for that matter.

A little research on the web indicated that the 12-804 and the higher pressure 12-803 sometimes get mislabeled. So I bought a rebuild kit which came with both springs. Swapped the new low pressure spring into the new regulator. Initially I could get the pressure in the 3 lb range but after a sort while the pressure would creep up. To make matters worse if I bounce the throttle I actually can watch the fuel pressure drop off (IMG:style_emoticons/default/hissyfit.gif)

The fuel pump is a Holley blue top so it has a max pressure of 14 psi.

My next track day is 2 Saturdays from now so I need to sort this soon. Has anyone else run across this before?

Thanks,

Miguel

[brant]

which mallory pump (part number) did you end up using?

I am still looking for a holley alternative myself

[Seabird]

which mallory pump (part number) did you end up using?

I am still looking for a holley alternative myself

Mallory Pump

Chris mentioned he uses the Mallory on his car, which for me is a pretty strong endorsement. And your reporting of going through the Holley's was another valuable data point.

Once I received it I was very impressed with the build quality. It might be a smidgen heavier though.

If you are going to mount it where the Holley was before you will have to rotate the body around on the bracket so the inlet and outlet match. At first it does not seem like it will rotate but it does. Slow and steady pressure will get it started.

Before I opened this thread, my search here on the forum turned up as many (subjectively) threads of people using the blue tops on carbs as red tops.... For future searchers don't go for the blue top if you are shopping for a pump.