Aeromotive FPR wont adjust to base pressure
 

So i am having a little issue. other than my car runs like shit and is way rich on PFC basemap with 550/1600 set up with a supra pump.

I cant get my FPR to set a base pressure of 40psi. when i turn the adjustment screw i can see it adjust from 20-32psi, but what i keep turning it pas that nothing happens on my gauge.

I am running the supra pump with the stock wiring. i checked it last night and its getting 10.9 volts with the diagnostic port jumped.

I also took some aluminum tubing and made my return into a gas jug just to see if i had some sort of return issue. but still had the same problem.

On this set up my feed comes out of thank to rubber line. down to a 10 micron inline fuel filter, to my factory hard lines, hardlines flared for -6 to primary rail, then secondary, then fpr side, with the return on the bottom of the fpr.

Got a tuning session with Mr. Ray Wilson on the 17th so any help would be appreciated.

you have the vacuum line completely OFF when adjusting?

i had a similar issue not long ago. Turned out my regulator was good, but my POS gauge wasn't. Make sure you have a good namebrand, fluid filled gauge.

yea, it wouldn't be pulling vaccum anyways. car isn't running when you jump the pump.

but even when it was running i tried it both ways. and didn't get the results i wanted.

but when you touched the throttle fp would jump to 60psi.

car runs like shit, shoots thick white/blue clouds of smoke that wreaks of fuel. It wont rev, and the exhaust manifold glows after some reving.

Did you use AN port fittings or regular AN fittings with the flare going into the Aeromotive FPR?

If you use fittings with a flare it will hit the FPR internals and cause problems.

Some other brands have picked up on this and made their FPR bodies thick enough you can use any AN fitting without interference.

I hope its something this simple.

check the spring inside. i have seen the break

i pulled it apart last night and its a very simple design.

first thing i check was the vaccum fitting hitting the spring, but i sealed that when i got it and its recessed with no clearance issues.

2nd thing i checked was the ball and seat for the diaphram, which was nice and chamfered.

3rdly i checked the spring which was fine.

lastlty the bottom port cant be seen, i have a different port fitting for that, but it should be fine. its not a flared AN on the fpr side, just an threads.


the only thing i havn't done was pull the supra pump back out and check the hose and fittings. Its a new build so this thing is brand new still. when i installed it it was the easiest mod to do for the FD.

so my next list is check the fuel pump, then the filter for debris.

when i first primmed the fp for the car i found leaks in my braided line. the inner hose had rotted and was spraying fuel out of the braid. i had a shop the hose and had them make me a flex-o-lite like black line.

so if any debris came from that old hose it would probably be wedged in the primary injectors, but i drilled and tapped the stock primary rail to accept npt to -6 fittings.

Attachment 674013

here is a pic of the setup, i feed to rear of the stock primary rail.

so i moved the fpr to right next to the fuel tank to test it. no filter. only about 12" of hose. same story. can't reach 40psi.

but when i get close the bump gets louder and i can hear a gurgling.

gonna pull the assembly tommorow.

I still say its a bad gauge ....

meaning you are running much higher pressure than what your gauge is telling you.

bad gauge sounds highly plausible to me.

update:

so swapped guages to a fuel pressure tester gauge from a kit. sames results.

so i pulled the pump assembly and tested the pump on a pan of gas and a battery... yea super sketchy.

results. the pump would push over 40 psi. so i set the regulator down to 40 and just installed it back into the car.... pretty much back to square one... but with more gas spillage.

https://www.rx7club.com/3rd-generati...-615964/page6/

Check out post #127
It basically bypasses the ignition switches that your fuel pump gets its power from. you will increase your pump voltage by simply wiring up the relay power source to a spare 12v wire that come directly from the battery.

so now the pump pushes the proper 40psi?

probably was a connection issue inside the tank if so.

and +1 to rewiring the fuel pump, you may also consider bypassing the stock connector on top of the tank. best to do it right once than do it twice and possibly cost an engine in the process.

you should also test that the rising rate is working properly by pressurizing the regulator port.

try this.


this is what happened to mine. The fitting interferes with the spring inside and you cannot adjust the fuel pressure.


back off the vacuum port or remove it and see if you can adjust pressure.