93LSivic

Stock 94 LS motor. Hondata 3b. RC 550's. 5-10 psi boost on large t3t4. SX 1:1 regulator with complete custom fuel system and STOCK intank pump.

I keep getting different responses. I talked to the shop I got my 3B from and they suggested 37-39. So I set the pressure how hondata says to do it by looking at the gauge and keep turning on and off the ignition so that the pump primes the system. Its set at about 38. Now with the car idling with the vacuum line attached it reads at about 30 psi !! I set it there and now the shitty autometer a/f seems to actually read in the stoich area on 5.5 psi boost. Kinda seems to run fine no hesitation or anything. I am kinda scared to boost on that low fuel pressure--especially with open wg cause there is no way of hearing any kinds of detonation.

Now one last question. I am using the SX 1:1 fpr, and i have 6an running from/back to the gas tank. Every time I prime the system by tuning the key on (not starting) and i run to look at the gauge under the hood, it will rise. BUT as soon as the pump is finished priming the fuel pressure drops right back down to zero. With the old setup it would hold the pressure for a long time--hours. Is this because of either 1) the return line is huge and just dumping the fuel back into the tank. 2) The fuel is leaking past the large 550's? --most likely not 3) Something is wrong with the fpr? 4) Since the diameter of the line is larger than the factory and has a huge inline filter, does the pressure just settle back to atmospheric in the lines between the pump and the regulator?

Sorry for the long post--but I dont wanna run into any kinds of lean conditions--especially when i spent a hell of a lot of money to make sure my turbo would be almost bulletproof to the stock motor.


[Modified by 93LSivic, 3:37 AM 4/24/2002]

VaporTrail

you should use the fuel pressure that your Hondata map was set to. If you are reading stoich on your a/m afr gauge, then you are running lean. Bump the fuel pressure.

TurboSedan

That fuel press sounds low to me. I may be wrong, but I think it should be closer to 50 psi.

93LSivic

Can anyone else add to this?

racerxadam

get the place that sold you the 3b to send you a copy of the rom. then we can see exactly what it is set at and we can change the pressure on the car and on the rom.

my fuel pressure slowly returns to zero also. i was under the impression that this is bad and that the fuel was leaking back throught the pump because my regulator is new.

rtype11

throw in a holley 12-916FI pump, you pump is fine at low fuel demand, but underboost cannot compensate, 40psi and up on 550cc is a good place to start so those guys who said high 30's were basically right, your pump cannot keep pace.