I have a 92 F150 with 170,000 on it. It has the in-line 6 (EFI). A couple of weeks ago she didn't want to start. It just cranked over and acted like there was no spark. I did some checking and determined the plugs, wires, cap, and rotor had almost 30,000 on them. The fact we are raining every day doesn't help with ignition problems either. Changed all of the above. A couple of plugs had large gaps but nothing looked out of the ordinary. Got it running, but she still doesn't start like she used to. I have fuel to the rail, but have not checked the pressure. The pump shuts off like normal after the key is engaged. I can flood it though. Checked all of the error codes and only come up with the Oxygen sensor on the exhaust as bad. The hole next to it probably has some effect on that. Shouldn't affect starting though. It appeared to be getting better, but she sat over the long weekend and didn't want to start again. If I barely hit the starter and don't crank for any amount of time she fires. If I crank more than a couple of seconds, I could crank all day and nothing would happen. I continue to get her started by hitting the starter in short bursts. Once she is warmed up she takes off with no problem. I'm starting to think it is a coil issue, but am not too sure based on it only occuring during cold starting. After these episodes she runs a little rough for 10 minutes and then runs fine until a couple of weeks go by and she has another starter episode. Anyone have any ideas??????

Thanks in advance.

 

I was thinking ignition switch.

 

I don't see how the ignition switch would turn the engine over but not allow her to fire. More information please.

 

When you turn the key to "run" it supplies power to your accessories and to your "ignition" system. (Using seperate wiring of course) When you continue to turn the key to "start", it drops the accessory circuit but, picks up the the circuit to energize the starter. There is also a connection to the coil while cranking. This is done thru a jumper in the switch. I'm thinking that you may have lost that jump and have no power to the coil when cranking, only after you let it go. This can be tested by using a test light on the coil to see if it has power in both positions. I could be wrong here though and maybe it's just a bad module.

 

Thanks for the explanation. I'll take a look at that. I am studying up on the wiring diagrams to understand what all kicks on and when. I am wondering if the ballast resistor could be the culprit.

 

I don't believe that you have one of those.

 

It's shown as an inline resistor just off of the ignition switch in the manual. Just a thought.