Hey everyone I have a 1995 yj with a 2.5l engine thats having a problem. I have searched around the forums and found people with kind of similar problems but not quite the same. So in the morning or after my jeep has been sitting for awhile when I go to start it the fuel pump doesn't kick right away. It will eventually kick to prime the fuel rail and it will do it twice and then it will attempt to start normally sputter and stall right after that. after 5 or 6 tries it will normally catch and begin idling and after that it will not have a single issue. While driving it will idle perfect at stop lights and never miss a beat. I have some ideas but I'm wondering what other people think. I'm guessing it's either the fuel pump going bad, the fuel pressure regulator going bad and not being able to hold presser to the rail, or a bad fuel pump or auto shutdown relay(because of the pump not always kicking on right away). I am wondering if anyone else has ever had this issue. Like I said most posts I found were people having similar starting issues but those posts always seemed to have other running issues after startup. I will emphasize the fact that the engine runs PERFECT once it starts it just takes a few tries to get it to catch and stay running. Any help is appreciate thanks!
Engine Starting funny
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Remove the fuel pump relay from its socket and install a test light in the 85/86 terminal slots, see if it lights up brightly when the relay is supposed to be kicking on. This will test the relay control circuit.
Before the first cold start of the day, remove the fuel pump relay, attach a ground to terminal 85 and power to 86 so as to trigger the relay, and check for low resistance continuity from terminals 30 to 87. This will test the relay contacts and control solenoid.
With the relay removed from its socket, install a short section of 16ga or larger automotive wire in the socket terminals to jumper 30 and 87 together -- the fuel pump should run continuously so long as the jumper wire is installed. This will test the relay feed circuit from the fuse to the relay and on back to the pump.
Buy or rent a fuel pressure test gauge suitable for fuel injected vehicles and connect it to the fuel rail test port. Start the engine and let it idle. At idle you should have approximately 31psi with the regulator vacuum hose connected, and the pressure should rise 8-10psi higher when you disconnect the vacuum hose from the regulator.
Before the first cold start of the day, remove the fuel pump relay, attach a ground to terminal 85 and power to 86 so as to trigger the relay, and check for low resistance continuity from terminals 30 to 87. This will test the relay contacts and control solenoid.
With the relay removed from its socket, install a short section of 16ga or larger automotive wire in the socket terminals to jumper 30 and 87 together -- the fuel pump should run continuously so long as the jumper wire is installed. This will test the relay feed circuit from the fuse to the relay and on back to the pump.
Buy or rent a fuel pressure test gauge suitable for fuel injected vehicles and connect it to the fuel rail test port. Start the engine and let it idle. At idle you should have approximately 31psi with the regulator vacuum hose connected, and the pressure should rise 8-10psi higher when you disconnect the vacuum hose from the regulator.
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