Fueling & Injection - Not getting fuel pressure
07-14-2012, 09:28 PM
Ok I'm trying to start up my motor for the first time and it's not starting. I've got a return style fuel setup with a regulator after the rails. When I switch the key on my fuel pressure gauge in the car jumps up to about 10psi then drops to zero. I tried adjusting the regulator and it still only jumps up to about 10psi. My fuel pump kicks on and primes like normal. What is my problem here?
07-15-2012, 07:35 AM
Could be a leak in the tank. [Assuming the pump is in there.]
Could be the pump is toast. Is it new?
How is the system plumbed?
Pump should restart once the PCM sees cranking rpm signal. Is it?
Psi on prime at 10psi won't work.
07-15-2012, 09:15 AM
Yes the pump is in the tank. It's a new racetronix. I did have a leak at my filler neck when I put gas back in it, I must not have got the hose sealed off. Plumbing goes: pump in tank to prefilter to the back of both rails to regulator then back to tank. I'll double check the pump restarting, I'm not sure but I know I was getting fuel to the rails.
07-15-2012, 10:00 AM
You mentioned 10psi at prime....A leak in the tank may not be a total failure, so there's enuf flow to show that 10psi...Given it immediately falls to zero is a ??, too. Again, it may be due to the intank leak.
07-15-2012, 10:24 AM
First thing you have to do is properly set the regulator.
You CANNOT set the regulator trying to prime the pump.
I see this far too often. People often keep cranking in the regualator trying to get the prime pressure up & when the pump first runs continuously the pressure goes way too high, blowing out hoses within the tank.
Jump the fuel pump relay so the pump runs continuously.
Attempt to set the fuel pressure... if you have to exessively turn the regulator in to get any pressure, fix your problem before proceeding. As you wind in the screw, the pressure should continually rise... if it stops increasing, you have other problems.
Since you just installed a pump, you may have an internal leak.... I hope you did not install the pump with a rubber hose.
Some regulators will bleed off pressure rather quickly & may cause starting issues.
Once you get the regulator set, you can start troubleshooting the rest of the system if it is still not working correctly.
07-15-2012, 04:54 PM
I wasn't really cranking up the regulator much but just enough that I thought my gauge would show an increase. I screwed it back out after I saw it didn't help. As for the pump I had installed it before I put my new motor in and it ran fine with the old motor. The only thing I've done to it since was remove the regulator in the bucket. What's a leak in the tank? And how do I jump the relay?
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