justinCO

I'm trying to get my Aeromotive FPR set correctly. I start the car up and let it idle and move the adjustment screw til it shows 50psi. Drive the car for a while and come back home. Check the fuel pressure again (from gauge in engine bay) and the pressure is down to like 43psi at idle. I try adjusting it again but now it's not going up any higher? I leave the adjustment screw in a few turns tighter from where I had it previously set and go drive some more. Check the fuel pressure while out at Checker auto, it reads 60psi??? So I adjust it again with the car idling and get it back down to 50psi. Head home, check it again and it's down to 43psi again?? Is this normal? How am I supposed to set a base fuel pressure when it keeps changing like this? The instructions say to adjust the FPR at idle with the FPR vacuum line unhooked. I tried that too and it mostly just doesn't want to adjust at all. Am I doing something wrong? BTw, I'm running a GSS342 intank and 450cc injectors w/ the 1:1 FPR.

Justin

justinCO

ttt...Anyone?

Justin

SJP0tato

Sorry, no help here. But I've got the exact same issue, only with a different FPR. Set it for 42psi at idle, drive around for awhile. Usually it's still at 42, but ocassionally it'll just drop to 36 or so. No reason as far as I know, all measurements taken with the vaccum tube disconnected. I'm very curious to see if anyone's had this problem also and been able to solve it.

Ryan P.

Arturbo

I have the same problem. In the morning, I look at the guage and it reads Zero. So I prime the pump to build pressure. I usually let the car warm up to get the accurate reading. Not that warming up has anything to do with it, it just seems to work out that way.

art

justinCO

So did you just set it once w/ the vacuum disconnected then leave it at that? I know it goes down when the car is off and then pressurizes when the ignition is turned on. I'll just set to the pressure it should be at with the vacuum line off and leave it as is.

Justin

Arturbo

Yes, I just set it once. Ive heard from others that the aeromotive doenst hold pressure when you shut the car off. Ive never checked on the stock fuel reglulator, but Im pretty sure it holds pressure when the car is shut off.

art

VaporTrail

fuel pressure will increase slightly as the motor warms up, as the fuel is being cycled through the fuel rail, which is exposed to heat from the manifold. Heat expands the gas, pressures might go up a tad. Shouldn't be quite to your extent though - does your rail use the phenolic spacers? Those are important...

Arturbo

uhhh, whats that?

boostaholic

What type of AN fittings are you using? Earls? On all the SX, Aeromotive, Paxton, etc. fuel pressure regulators, you need to use a different type of AN port style fitting or if you're using the flare ones like i do, you have to cut off the neck of it (the flared in tip) so the opening of the fitting is large enough to get fuel flowing freely to the holes inside the FPR. I had this problem the first time i used my SX FPR and talked to a tech at SX. Turned out the "flared in" necks on the Earl's fittings were restricting the fuel flow to the inlet/outlet ports on the FPR.

Arturbo

That was some good info boostaholic.

rjardy

Phenolic is a composite material, composed of mainly fibers of resin and fiberglass. Its used allot as a spacer because it hold shape and is pretty well heat resistant. So phenolic is really just a composite, now the spacers he is talking about? I dont know where he is talking about.


Rob

justinCO

I'm using Earls -6an unions to connect my FPR inlet/outlet holes to the swivel fittings. So you're saying I should pull my union fittings out and cut off the flared compression end of the fitting that goes into the regulator? I was actually wondering if that would affect anything when I was hooking up my fuel lines, since the FPR has no need for the compression fitting. Thanks for the info.

Justin

boostaholic

Yup, make a cut just below the threads to get rid of that neck. If you take off the FPR and look inside the ports, you can see the little hole that the fuel flows into the diaphram. Then look at your AN fitting and you can see that where the union reduces down to that neck will block off that hole inside the FPR. My SX holds pressure steady as a rock now and only increases with a change in vacuum/boost.