My '02 Explorer, with 80K miles, failed to start twice now in the last week. It cranks fine but won't start. By time I got it into the dealer's hands it was running. They could not find any codes stored in the PCM.
I've replaced the fuel pump relay, but it failed even with the new relay.
The second time it failed, I'm pretty sure that I did not hear the momentary turn on of the fuel pump when the ignition was switched on, but I'm not 100% sure because I was in a noisy environment.
I've ordered the wiring diagram so I'll know exactly how the fuel pump is powered and what/where to measure.
So, I'm preparing to troubleshoot the problem. Here's what I plan to do the next time it fails to start:
1) Check for spark at one of the spark plugs. 2) Check voltage and current at the fuel pump inertial cutoff safety switch. If there's no current then I'll check the voltage on both sides of the switch to prove that the switch had not failed "open". 3) Check for voltage and current at the fuel pump fuse. 4) Check voltages at the contacts of the fuel pump relay. 5) Check the fuel pressure at the fuel rail's Schrader valve.Does anyone have any other tips on how to troubleshoot this intermittent and annoying problem?
Thanks much.
Bob