so ive been trying to fix this issue since i swapped a tII motor into my car here's whats happening,
Fuel pump primes, car will start and immediately loses fuel pressure (drops from roughly 30 psi to half that or less) and dies.

setup: i have a walboro 255 fuel pump, new 3/8" aluminum fuel lines, no kinks in them, fuel filter only has a fuel thousand miles on it, AEM adjustable fuel pressure regulator.

there are no fuel leaks anywhere, i have checked, double checked and triple checked for kinks.

the fuel pump is wired directly to the battery for the time being using i believe 6 gauge wire because my car decided it didnt wish to turn on the fuel pump after by itself anymore, despite my asking it to nicely.

what could be wrong!? ive tried another fpr, ive tried a different fuel pump, what could it possibly be? all that i can think of thats left is an electrical problem.

any ideas would be appreciated.

 

You might want to include the details of how you have the pump wired up if you believe its an electrical issue .

 

took the power wire from the wiring right above the fuel pump itself in the hatch, strait to the battery using the same gauge wire as stock. the ground was left alone, i just now tried rewiring the ground to the chassis and that however also made no any difference.

 

If the ground wire at the pump is properly grounded and the pump voltage wire is wired to the battery for constant voltage then what prevents the pump from running continuosly whether you're using the car or not?

 

im just trying to get it to run right now, once that happens i'll fix it.

 

Yer throwing us off. You say the fuel pump PRIMES and then you start the car.

The word PRIME indicates or means to some of us......the pump runs for a few seconds and then shuts off. That would be priming the fuel rails. The pump running all the time does not mean priming the fuel rails.

That makes one think that the pump is NOT running all the time as you indicate later on this thread. IS the pump running all the time or not when your starting the car?

IF the pump is running all the time you should be able to hear the fuel retuning into the tank continuously. Is it heard returning to the tank continuously or not? If not then the fuel system is not plumbed right.

Fuel should leave the filter.....enter the fuel rails........exit the FPR and return to the tank continuously over and over and over and over and over.

 

sorry when i physically made the connection to the battery i heard the fuel pump turn on, it then runs continulously until i decide to break the connection. the fuel pump IS running full time.
fuel is leaving the tank, through the fuel filter, through the fuel rails to the FPR and back out to the tank.

 

When the car dies can you still hear the fuel pump running?

 

yes

 

you can hear it clear as day, no change in tone, no nothing..

 

Readjust the FPR to a higher pressure? Normal reading prior to the engine starting is 37-39 psi and then when the engine idles it drops to 28-32 psi approx.

 

i turned it up to ~40psi and it ran slightly longer but still died none the less. we're talking it runs for a second or so

 

Turn it up even higher????????? Just curious as to if it'll run a bit longer or not. Turn it up to sixty.

 

ive tried it, im not sure about to sixty but atleast 50. it doesnt really do much more, as soon as the car starts running you can watch the fuel pressure guage start dropping. and it dies once the fuel pressure has fallen to ~15 psi

 

im going to tear the entire fuel system down tomorrow and check for a blockage. there must be one somewhere..

 

Finally found the problem!
I had JB welded where the screw goes into the pulsation dampener to prevent future leak issues, i had done this on my n/a setup and it worked fine, however it must have caused a problem this time! not only does she run, but it has quite the lopey idle.. if i ended up with a ported motor man will i psyched!

 

and so now you know, dont screw around with the fuel system. especially with things like epoxies. i just dont trust em on high pressure situations.

 

yes lesson certainly learned, but man if that pulsation dampener causes my car to burn.. i am going to be some kind of pissed off!