Do this....pull the vacuum/boost hose off while the car is idling...fp should be around 60psi. If so, use anything to get some pressure to that hose while you are idling and see if the fp goes up like it's supposed to. I used a bicycle pump rigged up and my friend said "yup it's moving". If it does, make sure you are on the correct side of any check valves. maybe readjust the regulator. mine and 2bseens needed to be readjusted a little after it ran for a few days. Dunno why but it did. You could run a 10 gauge wire from the terminal on the back of the alternator to JUST before it goes into the tank...should help voltage drop and give ya a little more voltage. I ran mine that way for a bit before i got the boost a pump and then an extra pump.

 

That is an excellent suggestion Cable. Thanks for the idea. I'll try it today and let you guys know the results.

Mike

 

Cable, you're the man. I hooked a bike pump up to my FPR and built up some pressure. The FP did spike acordingly, but I also noticed a nasty hiss coming from the FP set screw. It's leaking out the boost at an alarming rate. I'm not sure why it's doing this with boost and not vac, but who cares. I've at least found the problem. No wonder my LTFTs spike up after 71% TPS.

Thanks for the suggestion Cable.

Mike

 

OK I spoke to Aeromotive. They said that minor leaks on the Boost Referenced FPR's is normal and would not cause this problem. Due to the high CFM rate of the S/C and the extremely low comparitive CFM of the leak, that can't be the problem. We ruled out a vacuum line issue, do to the fact that my boost gauge and surge valve reference off the same line and seem to be working fine.

So that leaves us with fuel supply. Everyone told me that the Walbro GSS340 would be able to handle what I'm throwing at it. I was told it could handle 550RWHP, which I'm not even close to yet.

The tech at Aeromotive did some quick figures and found that my pump is very close to the limit with my 42# injectors at 60psi of base fuel pressure.

So what could be going on? An obstruction in the line? I'm using an Earl's fuel filter cause I couldn't get a seal on the stock filter. I had to rework that section of the fuel line and needed a -6AN earls filter instead.

Could it be voltage? Some people suggested running a line directly to the battery, or unregulated source to supply power to my pump. I decided to hold off on this idea for several reasons. 1) With all the testimonials I didn't think I would be even close to the limit on fuel supply, so why make the install messier and more complicated. 2) I like being able to pull a fuse in the fuse box and being able to shut the pump down. 3) The batteries voltage fluctuates. So if I run my current directly off the battery my current to the Fuel Pump will fluctuate as well, giving me inconsistant Fuel pressure. (although in retrospect the FPR handles FP, the fluctuation in the pump merely will alter the max flow of the line)

Could it be an inproper installation? This is my first time with all this stuff, so I'm not ruling myself out as the missing link here :p I would think it's an all or nothing situation back there, but perhaps not. Could improper instalation limit flow?

What do you guys suggest? It's hard to trouble shoot spark blow out when you have issues like these lingering over your head.

Thanks for any suggestions,
Mike

 

Part of the problem may be your high base pressure - sure the pump massflow is going to drop proportionally to pressure increases. Since you still have headroom in your injectors you might try dropping you base fuel pressure to 45 psi or so with the vacuum line disconnected - and reprogram your IFR tables accordingly. This should give your pump more "headroom" to increase the pressure when you see boost.