Fuel pressure inconsistency run to run Aeromotive

[Rusty Davenport]

On my stocker build the first outing went great but with one catch.......from run to run the fuel pressure may be up or down 2-3 pounds. This is a textbook Aeromotive bypass system A1000 pump with Aeromotive regulator and all textbook fuel line sizes to work with carbureted engine in this case a Q-Jet. Before I start throwing a regulator or pump at it COULD it be a bad carburetor function ???? May sound crazy but the carburetor does control resistance to pressure doesn't it ???? Help please.

[Dave Ribeiro]

Try a couple different makes of fuel pressure gauges & make sure you check it while the car is running ... Compare with fuel pressure @ 1000' on a pass...

[Rusty Davenport]

A little further clarification----there is no difference in gauges of Autometer on the cowl and Aeromotive at the carb, they are consistent with each other. The car can sit still for an hour or the next day and have a different pressure everytime it is started and can be higher or lower from where it was at the last run. ??????

[Mark Lewis]

fuel cell vented? Or had one system on a Superstocker that the fuel line had gotten sliced where the fitting was put in and the liner was getting sucked in when a lot of pressure was on and collapsing the line.
Took awhile to find that one and it was on a carb system.

[buzzinhalfdozen]

You have the same system I run, what about voltage? Have a way of monitoring it, pump output will change with varying voltage.Merely a guess as I've never had that issue using their products.

[Jim Kaekel]

X2, three very good areas to look at.

[Danny Ashley]

What size needle & seat is in your Q-jet and what fuel pressure are you running? Larger N&S's don't like a lot of pressure. Also, how much pressure is at the regulator from the pump? One of my customers once told me he spoke with a Tech at Weldon and he said a Q-Jet should not have more than 18 lbs. to the regulator. Anymore and it "overworks" the regulator. Lastly, the ideal location for your regulator is in front of the carburetor, not to the side, and "soft" mounted according to Product Engineering. This allows inertia to work for you instead of against.

[Jeff Niceswanger]

If its the large N/S like Danny always put in ours, 5.5 lbs is about all they like . Some of them will go 6 , that's it ...

[junior barns]

Originally Posted by Jeff Niceswanger

If its the large N/S like Danny always put in ours, 5.5 lbs is about all they like . Some of them will go 6 , that's it ...

What happens when you go over 6? Does it start to flood out or just hurt performance?

[Mark Yacavone]

Originally Posted by junior barns

What happens when you go over 6? Does it start to flood out or just hurt performance?

I would say that the first thing you will notice is it will start hard .Look for smoke or vapor after shut off. It can't be good for anything to wash the cylinder walls on every start.