Hi

Hope everyone doing well. My fuel pump was hard wired with ignition previously by some unprofessional mechanics. So it runs continously when I turn on the ignition.
Now I connected it with original factory wiring. It is doing what it should like it should prime for 2 seconds with ignition on.
Now my problem is if I wait for it to prime then it starts up but is almost dying so I have to give throttle to keep it running.
And if I would not wait for it to prime, it will start cranking and will never start.
This is happening even if I shut down it only for 10 to 15 mins.
Means the pressure is not holding.
Also note that when fuel pump was directly connected to ignition, the car was starting in half crank.
2 causes comes to my mind
1. My injectors are leaking as my fuel average is very bad and exhaust smells like unburnt fuel
2. The check valve in the fuel pump is not working.

I want to know is there any other possible cause for this.
And can anyone confirms that when I start cranking, the fuel pump relay should engage due to the starter signal, not from the ecu signal? Ecu only responsible for priming and when engine is running?

Thanks
Car is Civic 2000 with D15Z6

 

Try replacing that fuel pressure regulator wont hurt to have a new one on! I'm pretty sure that's your issue.

 

How you came to that conclusion? While running, it's perfectly fine in every rpm range.

 

Edit i meant the FPR. sounds like its not holding psi