No start - sometimes

[TNC]

Can anyone give me some advise? My Explorer (1998 Sport 2DR 4.0 4x4) will not start. This happens for a while and then it will start. When it will not start, I cannot here the pump prime when the key is switched on. When I do hear the fuel pump, I know it will start. I checked the inertia switch and it does not seem to be tripped. Can the relay going bad cause it to start sometimes and not start others.

 

[TPLYNCH]

Check the relay in the black box under the hood. Next time you don't hear the fuel pump whine when you first turn the key, pop it open and jiggle the relay while the key is in the start position. If it is the relay, you will hear the FP start to whine. You can also try switching it with another of the relays - A/C should work i think. If you don't want to wait til then, try replacing the relay and cleaning the contact points.

 

[TNC]

I replaced the relay an hour ago, but problem was not fixed. It will still start for a while, then all of the sudden it won't. I'll hear the click, but not the noise after that when it doesn't start.

 

[Turdle]

Ok
it could be the pcm relay

notice if when you don't hear fuel pump, the check engine light is on.
it should be on with key on. If it isn't, PCM has no power, therefore niether does fuel pump.

PCM relay is larger sized than the fuel pump relay.

 

[TNC]

Jon and Tom thanks for the help. But, do you have any more suggestions? Earlier when I stated it was the fuel pump relay that I replaced, it was actually the PCM. I had been reading threads on here about possible problems like mine and these two relays were mentioned. I switched the fuel relay with another one (Blower relay I believe) and problem didnot quit. Did not know which one to switch with the larger PCM, so I went to Advance Auto and asked for a fueal pump relay. I had the PCM rekay with and that is what the parts guy bought me. Either he didn't want to acknowledge my lack of automotive repair knowledge, or he didn't know what he was doing. As you can tell, my automotive repair skills are limited. I appreciate any and all tips that anyone has to offer. thanks again