I had stopped for lunch after about three hours of trail running on a hot day. When I tried to start it up it revved up really high then died and would not start again. After narrowing the problem down to loss of power to the fuel pump with the ignition on, we hot wired the pump to get it started then it ran fine all day. Now everything's back to normal. As of now when I turn on the ignition switch the pump primes then shuts off and the jeep starts up fine. Besides the question of what's wrong I would like a little education on how the fuel system works.
Is the prime (turning on the ignition) the only time the fuel pump works or does it come on intermittently?
Why doesn't it run continuously?
What tells the pump to shut off?
BTW, it's a 1989 4.0 automatic
Is the prime (turning on the ignition) the only time the fuel pump works or does it come on intermittently?
Why doesn't it run continuously?
What tells the pump to shut off?
BTW, it's a 1989 4.0 automatic