wonder1and

I now have the keiths rails setup on my car w/ 1600's connected via braided lines and fittings to a threaded primary rail... my FPR's gauge will drop pressure fast after turing the car off... anyone have any ideas what could cause this? I was told it could be a possible bad seal on my fuel pump... also I don't smell any fuel in the engine bay...
Any ideas? Thanks,
Ryker

rxrotary2_7

could be a bad seal.... my aeromotive pump will drop off imediatly. there is no check valve. check your PM's

BLUE TII

iTrader: (9)

Yes, I have the Aeromotive dual port and it drops off fairly quickly once car is off- usually down to zero pressure within an hour. No fuel smell.

pp13bnos

iTrader: (1)

On my non turbo 90, I had a check valve inside of the fuel pump fail on me. You would have to crank and crank on it for it to fire. Swapped to a t2 fuel pump and the problem was solved. CJ

88fc3sw/HX83

This is a "common" issue, I'm using the Cosmo fuel pump and my fuel pressure drops off after shut off also. I don't think its a fuel pump issue, probably somewhere between the fuel lines, rail, injectors, and FPR. With all the custom fittings, lines, and injectors, it could be anywhere within the system.

wonder1and

Maybe a check valve... I've got a RP fuel pump...? Hmm... damn still stumped... I'll check on the pump w/ Rp tomorrow...
Thanks,
Ryker

lane_change

iTrader: (20)

Well since we are on the issue of fuel pressure, here is my problem/question.

I am running an SX FPR with Keith's rails in parallel. I am running -8 line to and from the rails and also for the return line from the FPR. So I had to buy new fittings for my FPR since the ones that came with it were -10 and -6.....not my size. So I installed some Aeroquip -10 to -8 Flare fittings and they hit the inside of the FPR when they are tightened which allows 0 fuel to flow into the regulator....can I simply shave the bevel off of these fittings or do I have to buy new fittings. If I have to get new fittings, where can I get fittings that will fit the SX FPR. The -10 ones I got were chamfered from the factory...those would be nice to get, but I can't find them anywhere.

Any help would be great. I am planning on shaving my two fittings down tomorrow.

Thanks,
Scott

Also, I run the A1000 and have 0 fuel pressure after shut-off as well....it falls almost instantly. Which is odd since it takes a ******* year to build up due to those fittings hitting the back wall.

RotorJoe

Could the injectors be leaking after power is turned off? Not to say that the injectors are bad, but could that condition occur? I don't know just throwing out suggestions.

mks

You need AN O-ring boss, not AN flare adapters to hook up your regulator. Don't shave your flare adapters, they won't seal since they don't have the o-ring.

You need this:


Not this:

lane_change

iTrader: (20)

I shaved them down and they work fine. I can prime the system now and have 45psi within seconds. I will buy some boss fitting for it, but these will do for now.

But I broke my coolant temperature sensor that connects to the water pump housing, the one that the green clip goes to. I know this goes to my ECU which will give me a Water Temp reading....so my car was idling some without knowing temps...I just left the fans on the entire time. I was trying to get my cooling system burped some, since the new motor has alot of air in it, but I don't know if the thermostat ever opened to push air through the system so I could bleed it. I did not want to risk the motor, so I shut it off, and I am going to try and find a new sensor tomorrow for it.

I did try and drive my car around my neighberhood block and it stumbled and **** all the time....my fuel injector duty cycled was up to 34% at 2600rpm....so I think I am pumping way too much fuel and causing it to stumble when I press the gas much above 2000rpm. Or could it be that sensor being broke, putting my car in some sort of limp mode?

Thanks,
Scott

Pg-Unlimited

The stock fuel pump has an internal one-way check valve that forces the pressure to leak down through the stock pressure regulator. Check the workshop manual, it has specifications on pressure loss after shut down to check this process. Once the fuel pump is replaced with an aftermarket unit, this check valve is gone thus your pressure moves back into the tank via supply line. If the situation bothers you can buy a check valve from AeroMotive but they are expensive, use -10 AN fittings, can't get any flow charts, and decided to live with the problem with my Weldon Racing pump Hope this helped your problem