Fuel pressure drop - Third Generation F-Body Message Boards

Drumer919 · 03-18-2009, 01:02 PM

Today I got my fuel pressure regular modded and turned the FP up to 15PSI at idle but I notice that when I give it gas with my hand standing there so I can watch the gauge it drops down to only about 9PSI, is the initial drop normal and it will build back up after a second or so or is it a sign of the pump not being able to keep up with the demand? Also is a TPI pump a sufficient upgrade or do I need something more?

RBob · 03-18-2009, 02:47 PM

There isn't enough fuel delivery. It could be a clogged filter, if not then the pump can't handle the flow at that pressure.

A TPI pump is OK. Not knowing the HP level can't say whether it is enough pump or not. Note that at 15 psi it will be flowing a lot more fuel then at the normal 43 psi of a TPI system.

When you do the throttle blip test the fuel pressure needs to remain rock steady.

RBob.

Drumer919 · 03-18-2009, 03:12 PM

Thanks RBob, the fuel filter is brand new so I guess that means its a weak pump. With the old cam and a 750 Double Pumper the motor made just shy of 400hp at the wheels in my TA without spray. No N2O on the truck though. Man I wish I wouldn't have flipped that car.

thomas1976 · 03-18-2009, 04:18 PM

Could also be the FPR spring being too weak.