Question on loosing fuel pressure going down track.

[jim morgan]

Or maybe you don’t have a problem, Before all this high pressure,high volume systems
I had a max wedge , Carter electric and manual pump had 6 pounds thru the lights at 2 pounds went 127.5 mph that’s 30 years ago, is your car nosing over, ?

[Jeff Stout]

Originally Posted by jim morgan

Or maybe you don’t have a problem, Before all this high pressure,high volume systems
I had a max wedge , Carter electric and manual pump had 6 pounds thru the lights at 2 pounds went 127.5 mph that’s 30 years ago, is your car nosing over, ?

With it being a fairly new combo to me. My opinion is that it is not nosing over as the mph matches the et. Side note is the o2is going from 13.5 to 11 in high gear.

[Greg Hill]

What brand of pump do you have? A q-jet is notorious for being hard to keep supplied with fuel. When I built my car it had a 780 Holley and I was using a Mallory 140 pump and a 3/8 fuel line from the tank to the regulator and everything worked great. When I switched to a q-jet combination I ended up switching to a Barry Grant 280 pump and a 1/2 inch line from the tank to the regulator to get it to run right. The amount of fuel to a q-jet is critical.

[Alan Nyhus]

Take the line off at the carb, run the fuel pump for a full minute and measure the volume it pumps. Do this with the gas cap on and off to see if there's a difference. -Al

[Nick_Siebert]

I had the exact same problem become present on my 305, Q Jet Camaro, it was a faulty pressure regulator at the carburetor.

[rod butcher]

A friend had this same problem this year and found it to be a very restricted fitting from tank to pump. This was after he changed pump and regulator. It was a 90 degree fitting.

[Ed Wright]

Is this a stock fuel tank? Not a fuel Cel?
To eliminate a weak (low volume) pump, I would add 5 gallons of fuel. If that stops the pressure drop, it will usually indicate the pump pick up being uncovered due to placement in the tank.

[Jeff Stout]

Originally Posted by Ed Wright

Is this a stock fuel tank? Not a fuel Cel?
To eliminate a weak (low volume) pump, I would add 5 gallons of fuel. If that stops the pressure drop, it will usually indicate the pump pick up being uncovered due to placement in the tank.

It is a fuel cell with about 10 gallons in it mostly to make weight. Has rear sump and exit with pump directly behind it. Im pretty sure I 45 degree or straight fitted everything. I did install a -8 inline fuel filter when I built car 35 passes ago.

[Mark Yacavone]

It's the G force causing the problem.
;-)

[Dave Noll]

Originally Posted by Jeff Stout

Side note is the o2 is going from 13.5 to 11 in high gear.

Trust the sensor, there isn't a problem. Its 11:1 in high gear. My cars AFR gets leaner as RPM increases an gets richer at each shift. (completely different carb)