Fuel Setup:

1x walbro 255 in tank in stock fuel pump housing > -8an feed > 'bout 1ft -8an line into 1x external walbro 255 inline > -8an feed > atp fuel rail > 4x 1kcc injectors > 'bout 1ft -6an return line into aeromotive a1000 FPR > -6an return all the way into stock return port on fuel pump housing

Both fuel pumps are hard-wired to the battery using 2-way rocker switches... both lines are 10 gauge w/ 20amp in-line fuses. Both pumps are grounded properly. Both pumps sound healthy when turned on. This setup has worked PERFECTLY for 'bout 2 weeks without a flaw... until tonight.

What I Did:

Got in the car and tried to turn the car on without turning on the fuel pumps (forgot)... tried to crank it once and it would not crank obviously (I've done this before without any problem, just doesn't turn on). Turned on both pumps like usual and tried to crank the car... won't turn on.. Tried 'bout 3-4 more times, nothing. Turned off external pump and tried to crank the car with internal pump only, cranks 1st try. Idles at normal a/f then begins to lean out rapidly all the way to "- -" in which then the car sputters and dies. Tried to turn the car on again with only internal pump on, cranks fine again. Tried to immediate turn on pump# 2 with the car on, car instantly dies.

Fuel Pressure Gauge Readings:

NO pumps on: 25psi (wtf)
Intank pump ONLY on: 120psi (needle goes past the 100psi mark abd rests on the last plastic piece... WTF)
Intank AND Inline pumps on: 0psi (wtf wtf wtf)

Before tonight, the FPR was set to read 44psi w/ both pumps on.

What I've Checked:

Both pumps turn on properly and whine properly... sound very healthy. Checked everywhere for leaks, none. Tried to smell for fuel leaks, none. Tried to touch the fuel lines with either one or both pumps on... either way, I can feel fuel flowing through ALL the lines (feed and return) both in the rear of the car and in the engine bay. Injector duty cycle seems normal for the few seconds the car idles before sputtering and dying. Car has at least 6 gallons of gas in the tank. If I try to blip the throttle cable while the car is idle'n for a few seconds, I hear a slight sucking noise every time... then the car dies... may sound like the injectors sucking the fuel rail dry... sound is similar to a NA honda with an intake but not as loud.


Suggestions? I'll provide any and all info needed if anyone has any idea what's going on... I'm currently waiting for a friend to come help me diagnose the problem before I proceed further by myself.

 

Being required to fiddle with switches in the first place sounds like a good beginning to a myriad of potential problems. Was it really necessary to do this?


Perhaps you somehow damaged the FPR. Given what you've reported, that is the first thing I'd suspect. After all, there just isn't much else that can go wrong assuming the pumps are working properly. If you have another you can try, I'd do that first and either confirm or eliminate it as the source of the problem.

 

The switches are used just as my preference of controlling and wiring the pumps straight to the battery using 10gauge wires.

So I went out and purchased a brand new Aeromotive A1000 -6 FPR and Summit gauge... installed them as well as an Aeromotive 10micron in-line post-pump fuel filter as an increased safety element. After installation, set the fuel pressure to 44psi w/ both pumps on while the car idles. Car cranks and drives 100% fine with the new parts.

Now here's the kicker... about 6hrs after driving the car around with everything working fine, we did some more misc. work on the car and accidently drained the battery. We put jumper cables on the battery connected to another car and I turned on both pumps and turned the car on... cranked the car perfectly... idles perfectly at normal a/f's... however, the new water-filled gauge is pegged @ 100psi stuck no matter what. However, the car still drives and runs fine EXCEPT for the fact that under boost @ 20psi and higher, the car begins to go very lean... normal a/f's should be around low 11's but jump to 13's at this boost lvl. The adjustment hex screw was never touched after 44psi was set. This lean condition only happened after jump starting the car and destroying the new gauge.

Now I'm going to try to locate a new gauge and see if my fuel pressure has somehow gone to ****s on the less than 24hrs old FPR. Any other suggestions would be appreciative... thanks.

 

A solid suggestion would be to lose the two pumps and switches, and revert to the factory single pump setup using the modified pump sold by Buschur. It's simple, and it works.

No extra pumps, no unnecessary switches, and no more problems.

 

Ted has Dave released any info on the flow rate of his new pump, and the HP it can support?

 

I haven't seen any flow data, but it is apparently sufficient to fuel this car without issues:

https://www.evolutionm.net/forums/sh...d.php?t=215262

 

I think I've solved my own problems... at least I hope so.