1G Fuel pump relay

[Johnny123]

ok so my fuel pump, (forced performance 255lph) wont prime when i turn the ignition on. i have to turn the motor over once for it to start prime. After it primes it usually starts normal but sometimes it takes a couple extra revolutions to start. and also i put a new sending unit in. it worked for about a day but the fuel light stayed on. didnt really mind so i rolled on with it. but now its reading full and i know its not. any advice would be appreciated

 

[And_44]

I believe fuel pumps turn on when the starter was engaged and when the engine is running. When running the CAS sends the signal to keep it running.

You check your fuel pressure regulator at the end of your fuel rail or for any leaks in your line that may relieve pressure on the system when car is off?

 

[Johnny123]

Yes Their are no leaks. and if that is the case then why would i have such hard time starting it? it would atleast take 15-20 secs to start if i just turned the key and let it turn over. i just pop the key once quick time and i can here the pump run. then i turn over again and it starts up within 1-3 secs.

 

[steve]

I believe fuel pumps turn on when the starter was engaged and when the engine is running. When running the CAS sends the signal to keep it running.

Correct. 1Gs only run the pump while cranking and while the ECU is seeing CAS pulses.

If you're having a hard time starting the first place to look is at the pump and make sure the o-ring between the pump and pickup tube is sealing. Fix your level sender float while your in there.

 

[Johnny123]

ok well when i installed the fp pump i kinda just used some fuel hose from the pump to the pickup tube with some clamps. so i eliminated the o-ring. would that create the problem? it was working Perfect until a couple weeks after it was said and done.

 

[Johnny123]

Turns out i only clamped on side of the hose. guess i thought it was tight enough fit it wouldnt leak on the pump side. finally got a minute today to tinker with it and i clamped it. still same problem. would my factory fpr play a factor? when i have the car running and turn it off then back on (within 30 sec) it starts up normally. its like the fuel system loses its pressure after shut off.

 

[9!'clipseDOHC]

I have the same problem but no solution. I'm subscribing to this thread in hopes that you find the answer.

 

[And_44]

You check your injector seals and fuel line running to fuel rail after you let pressure system pressurize. Look for fuel leaking.

If you have no problem in starting the car after it's been off for a short time there is still pressure in system but if it is having a hard time starting after a long shut down period I'd look at either a leak in fuel system, faulty pump or fuel pressure regulator. The regulator has a diaphram inside of it and it could have a small hole or tear that allow fuel to drain back into tank.

 

[Johnny123]

im going to try capping the return on the fpr to test it. would this create a problem with the motor? i know it will put full impedance on the injectors. and i just did a fi cleaner on it and didnt see any leaks at the rail or injectors. put it on the lift and couldnt find any either. thinking it s the fpr.

 

[steve]

im going to try capping the return on the fpr to test it. would this create a problem with the motor?

What exactly do you expect this is going to tell you? By blocking the return port the FPR isn't going to be able to do anything.

i know it will put full impedance on the injectors. and i just did a fi cleaner on it and didnt see any leaks at the rail or injectors. put it on the lift and couldnt find any either. thinking it s the fpr.

It's not going to change the impedance of the fuel injectors.

 

[luv2rallye]

i know it will put full impedance on the injectors.

Well that's one I've never heard before! I know he meant to say pressure but wow, talk about your spelling errors!

 

[Johnny123]

Steve: i tried it to see if the regulator was slowly loosing pressure in the system back into the return. turns out it worked and i need a new regulator.

Luv: Yes i meant pressure. I'm a dummy.