I've been tuning my new engine setup{403cid with 57lb injectors}but falling fuel pressure is causing me problems.With the stock fuel pump and the inline pump from Magnacharger I had about 48 lbs of pressure with the old setup{5.3 with 42lb injectors}now when I give full throttle on the dyno the pressure is dropping to 20 lbs.I replaced the inline pump with a Edelbrock fuel pump,that raised the pressure at idle through mid throttle to the 50 to 52 lb range falling into the 20lb range when full throttle is applied..Help,I need suggestions to stop the pressure drop.

 

Dual intank pump like parish has. Racetronix might make you a setup although it is not a stocked item. Just depends on how busy they are.

 

I'm trying to get the truck going tommorow,wife has begun to ask to many questions.I've thought about running a MSD boost-a-pump short term on the stock pump with the Edelbrock inline pump.The Edelbrock pump is rated to feed 835 hp@12 volts and something like 1290hp at 16 volts and can push 90 psi.The guy helping with the tuning is trying to talk me into putting a bulkhead fitting in the bottom of the fuel tank and running just the Edelbrock pump.

 

I would say the stock pump is crapping out on you. You could pull the module and stick a single 255L in there pretty easy and be on the way. I have dual 255's in the tank but so far I have only activated the 2nd one while using the spray. I would guess that a single plus your inline should be fine.

 

L-Eater,what 255L pumps are you running ,did you have any other issues when you installed them.If I could run one 225L intank pump with the inline I'm sure I would have enough pressure and if the fuel gauge still worked I be really happy.

 

If my memory is correct the number was GSS340M. (Walbro brand) and I think it is listed as being for a Bruick GN. You could use a pump for a Mustang. The only diff is the inlet. I mention the Stang pump 'cause I know it would be readily available in the Memphis area.

 

I think I already have a GSS340M new in the box at my office.I bought the pump over a year ago from Ramchargers and never used it.Do you have any issues with fuel starvation at low fuel levels?And does your fuel guage still work?

 

My local track opened Sat and I did find the starvation prob. It does slosh away from the pickup on hard launch at 3/8 tank. The gauge works fine, no probs there. If doing a single pump you might be able to keep the resorvoir, would hafta look at it to see, I cant remember. I can look at my old module in the morning if it would help.

 

Have you thought about replacing or checking the fuel pressure regulator?

 

I'll definately check the fuel regulator before I drop the fuel tank,thanks for the suggestion.