I finally (after 3 months) got around to ordering/installing a Walbro 255LPH Hi-Pressure fuel pump. Prior to replacement, my fuel pressure would read 51 for only 15 or 20 seconds, then it would drop to 45 or 46 and remain there. Now, after installing the new pump, I'm able to maintain 51 psi (or higher, if I'm so inclined). If any of you have been experiencing the same difficulty (and you are convinced that your AFPR is working properly), give this a shot...it will probably solve your dilemma.

 

Good find. I wonder what my fuel PSI was with the DE-K FPR, DE-K injectors, and stock pump.

 

thas strange there r many people with stock fuel pump with the stock and they claim there psi is fine, u might b right tho

 

i just installed one, and it's true, 51 psi is no prob. hell, 100psi is no problem.

 

Sadly, I have to edit my initial post. Now, for some odd reason, my pressure is back to doing the same thing...51 psi (and fully adjustable) for the first 20-30 seconds after startup...then 45-46 psi (and completely non-adjustable). WTF???

 

keep us posted, when u find out the problem

 

When you start the car, the fuel pump gets more voltage for 30 seconds making fuel pressure (supposed to raise) then after 30 seconds it goes back down. thats how it works to help car start and warm up. so always ignore pressure for those 30 seconds. and get a good quality afpr and gauge.

 

I already have a very high-quality Aeromotive FPR and gauge (my 3rd different brand). I kept changing parts because I felt one of them must surely have been bad...they weren't/aren't. I'm not planning on troubleshooting any of this as the car runs perfectly (save for a minor cold-start issue). If anyone can explain why I can't increase fuel pressure once it falls after 20 or 30 seconds (never have been able to with any of the components I've tried), I'd love to hear it, though. It's just that I'm done sweatin' it.

 

It should be noted that this only applies to vehicles that have fuel pump control modules (FPCM) which would be California models (95, 96) and all 97s. 98+ fuel pumps get battery voltage full time.

To bypass this, I would just run some power resistors in place of the fuel pump to keep the ecu happy and then wire the fuel pump terminal 2 straight to ground instead of through the dropping resistor.

 

Thanx for the extra info.

 

Just curious to what your cold start issue is. I have a loud crunch noise that happens occasionally, and sometimes I have a warm start issue, but that might be the plugs.