this is the usual my car wont start story it just cranks. i was trying to figure out why and i pulled off the fuel rails to check the injectors and low and behold there was no gas in the rails. SO i used a jumper cable to activate the pump while the key is in the "on" position and i can hear the pump turn on and hear fuel in the lines. When I try to start the car with the jumper cable still in the second i turn the ignition all the way i can no longer hear the pump untill i let go. I have no idea where to go from here. any help would be appreciated. thanks

 

fuel leak or bad fuel filter? do you have fuel pressure right off the pump while cranking?

 

no fuel leaks, and the fuel filter is new. The pump gets no power while cranking but operates fine with the jumper installed. I read in a post somewhere on here a logn time ago that it could be my AFM? is that true?

 

The pump should be getting power while you crank. Sounds like wiring or a fuse.

 

When you say JUMPER CABLE, do you mean your jumpering the fuel pump check connector in the engine bay? Yellow two socket outfit?

The circuit opening relay is what causes a pump to work or not work. When you have the key to ON and the check connector jumpered, you are putting a GROUND on one of TWO coils in the circuit opening relay, which in turn causes it to pull in and feed the pump thru the fuel pump relay/resistor package near the right front headlight assy.

There is another coil in that circuit openig relay. THAT coil is energized by putting the key to START which puts 12vdc on that coil. Then the relay pulls in and supplies power to the pump as described above.

Actually I don't thnk I can help you. IF the yellow two socket connector is jumpered and you hear the pump run when the key is to ON, then things should not change just because you now went to START. The relay should still be pulled in and the pump still running. Unless the ignition switch is buggered up and you lose the 12v going to the relay when the key is put to START.

Only a meter probing the relay could tell you if that is happening or not.

Well, got your thread back to the top of the list anyway.

 

thanks guys. Well after many hours of searching for the problem my pump started working. I didnt change anything out so it must have been a bad connection somewhere. I didnt notice any bad connections but i cleaned them anyways and it started working. Bad news is my car still wont start. ive checked for vacuum leaks, its not flooded, it has a spark. Last thing is fuel pressure right? is there anything else anyone can think of trying? oh and do the secondary injectors inject fuel on startup to? or is it just the primaries?

 

Just the primaries are supposed to open on startup. Yeah, check your fuel pressure after the filter or at the rails. And how do you know it's not flooded?

 

I did the unflooding procedures and it still wouldnt start. im hoping its not flooding everytime i try and start it but i am using S4 rotors which have lower compression and the ecu is s5 might be injecting to much but i have started it with this ecu before. The problem started after my car was broken into and they stole my power fc. i got a new one but im waiting to install it untill i can start it and warm it up so the power fc can do its learning process without dying, also i just wanted to make sure everything else was working.

 

I'm having this same exactly problem!

When I jumper the fuel pump and turn the ignition to "on" I can hear the pump whiring and I can feel pulses in the fuel lines from the filter all the way till after the FPR.

When I turn the key to the "on" position w/o the jumper wire I don't hear the pump. My car will start, and run for a few seconds, then it dies (sounds like when I kill it w/ the fuel cut switch) but it will only do this once or twice before it just turns over and refuses to even try to start.

Interestingly, after I jumper the fuel pump for 10-30 seconds, the car will start again.

What contacts/ conections did you clean to fix your problem?

 

Fuel pump only runs if the engine is running or the key is HELD to Start.

The exception is if the fuel pump check connector is jumpered, then the pump runs all the time the key is put to ON or better.

Make sure the afm plug is on the afm. And note that the ECU does not use the afm during the start procedure until your over 500rpm.

 

i cleaned all of them so i have no idea what one did it. i jsut took the harness out back to the firewall to check for possible shorts. As fas the afm i dont have one. Im running a power fc. i think the problem is my injectors arnt firing due to a wiring problem somewhere. Bad ground? anyone know what ground the injectors are on?

 

The ECU grounds the injectors to pulse them.