crazyrx7

I installed the rx7 store fuel kit (1600cc injectors and aeromotive pressure regulator) on my car. I understand that the base pressure at idle should be 28-32 psi. Well to get that pressure I had to screw in the pressure adjustment bolt on the regulator all the way in. My buddy has the same kit but his screw is half way out. I would of thought with it screwed in all of the way that I would have 70 psi or more.

After the car gets warmed up the pressure hovers around 25/26 psi. However when you blimp the throttle it shoots up past 50psi. Is that normal? Can it be that the aftermarket alternator pulley having a effect on the voltage on the system causing the fuel pump not to pump as hard? What pressure should I have at 16psi of boost? Did I get a bum pressure regulator?

R.K.

GARCO MOTORWORKS

Do you know how to set it up to start with , the first adjustment ?

mad_7tist

did u set the base pressure with the vac line off???

crazyrx7

Ya even with the vacuum line off it only goes up to 30 psi. If I back out the screw then it falls to 20 psi. The base pressure with the line off should be around 55psi correct?

R.K.

IRPerformance

iTrader: (41)

Where is the regulator installed? Should be in the return line. I like to set the base fuel pressure to 35-38 psi with the vacuum line off. You should easily be able to get that much. Try wiring your fuel pump to a constant 12v.

crazyrx7

Yes its in the return line. I will try it again tomorrow and see if I can get it to 35-38 psi. BTW I have a new fuel filter and a supra fuel pump as well. How much fuel pressure should I have at 16psi of boost?

R.K.

GARCO MOTORWORKS

If you set the base at 38 then at 16 psi boost you should see 54 psi fuel pressure . I am running 850 cc and 1680cc injectors with the base at 40 psi and the idle is very good .

NewbernD

iTrader: (1)

Sounds like he still has the fuel pump resistor in the mix.. Might that explain the lower pressure at idle than when on the throttle?

crazyrx7

What fuel pump resistor?

R.K.

GARCO MOTORWORKS

I have the resistor in the system and no problems.What resistor you ask , the stock system is set up to run the pump at slow speed at slow speed ,no boost and at a higher speed ,voltage when high rpm , boost is in play .It is located below the brake booster on the finder. It is a small fined alum part with a set of wires comming out . The wire colors are blue/red and white/red .

crazyrx7

It idles fine at 25-26psi of fuel pressure.

R.K.

maxcooper

Maybe there is some kind of plumbing problem. Describe the plumbing from the perspective of the fuel...

sitting in tank, sucked into pump
through OEM filter
up to FPD on primary rail
out the front of the primary rail, into secondary rail
out of the secondary rail, into side port on FPR
(the gauge measures the pressure of the fuel that comes in the side port of the FPR)
out the bottom of FPR to return line
through return line back to tank

My top guesses at what is wrong with your system (in no particular order):
* gauge plumbed in wrong place
* FPR plumbed wrong -- verify in and out ports
* plumbing way off -- make sure it goes pump-rail-rail-fpr-return
* big leak INSIDE gas tank (at fuel pump outlet) -- note that this will not leak fuel out of the car, so don't pass this over based on the absense of an external leak
* bad FPR

Work slowly, understand your plumbing, understand what it should be, verify that it is plumbed how you think it is, etc. I think you will find the problem with a bit of careful thought and inspection.

-Max

crazyrx7

The plumbing is as you described. The guage is installed on the pressure regulator itself so that can't be it. I double checked all of the lines and everything adds up. It leaves me with a bad fpr or leak inside the tank. Thanks for the responses.

R.K.

crazyrx7

I have narrowed it down to the fpr. My buddy is going to swap his out so that I can try it in my car in the next couple of days.

R.K.

crazyrx7

Quick question; on the drivers side firewall the three hard lines for the fuel and charcol filter, which order do they go in? If the supply was feeding into the return on the fpr and being fed out on the in of the fpr, would that cause what I am seeing for pressure? Would the fuel pressure still go up with a blip of the throttle?

R.K.

crazyrx7

Okay I figured out the hard lines on the fire wall. Everything is hooked up correctly. I verified that the pump is not leaking. The only thing left is the fpr. I will know in a couple of days for sure.

R.K.

crazyrx7

Here is a update. I finally fixed the problem. It turns out that Max was right. The mkiv fuel pump that I have had a bad O ring (actually it was warped and split in 2) causing the fuel to leak out. I replaced the O ring and behold I can adjust my base pressure to 38-40psi. I'm so happy that I didn't have to buy another pump.

R.K.

turb0x2

iTrader: (71)

awesome...good stuff!