94 Explorer won't start when hot

[talltimber]

new guy here and i have a problem. my daughters 94 explorer (4.0, auto, 4x4) has developed an intermintent electrical gremlin. when cold it starts perfectly, no starter drag, fires right up. once it reachs operating temps it will not start. the starter and solinoid will not operate. i do get a click out of the relay right behind the battery, but thats it. i have replaced the ing. key module (it was broken anyway, so i replaced it) i have also replaced the ign. switch module. so basicly i am working my way from the key to the starter/starter solinoid. i found this forum last night and thought i would give it a shot. any testing proceedures anyone might have to keep from buying unessary parts would be helpfull
thanks

 

[YBCold]

it might be a bad ground connection. i know first gen bat wires corrode from the inside out.

 

[92exp4x4]

Try volt dropping the starter wire and the starter itself. Resistence can go up with heat especially in electric motors, and with the starter so close to the exhaust, it may be affecting it. Put a volt meter accross two points of the circut and operate the circut. The voltage you see on the meter is the voltage lost during the operation. It is the lost potential due to resistance in the circut.

For example, put one meter lead on the starter relay and the other lead on the starter connector where the heavy cable connects. You should see 0 volts. With the meter hooked up have some one try to start the engine. If you see more than .5 volts on your meter, then you may have a problem in that wire. You can do this with any component in the system. I would say if you have more than 1 volt drop replace the component.

This is a much better test than ohming (continuity). If a wire has just one strand left it will ohm fine because you are using the small battery in the meter to check the wire. If you hook that same wire to a car battery it will fail even though it passed the ohm test.

Try this out and let us know what you find. Good luck

 

[92exp4x4]

I for got to say, check all the grounding straps between the motor and the frame, frame to body etc. The starter grounds to the motor and the motor sits on rubber mounts ect.. ect.

 

[YBCold]

im thinking it might be the engine coolant temp sensor. there are two. one is to the computer ( the one that might be causing you problem) and the other to the instrument cluster. it sometimes will make the car think its too hot or too cold and not send enough gas or what ever. I think the one to the computer has a grey plug and the one to the cluster is brown

heres a pic of its location - Engine coolant Temperature sensor

Let us know what you get

 

[hollywood.mike]

thanks for the sweet pic! i was just about to tackle this one due to my gauge on the dash not working! haha! damn i love this forum!!!!

 

[Tyexplorer]

Did replacing the engine coolant temperature sensor (ECT) solve the warm start problem?

My 94 with 127K miles starts but idles rough after reaching operating temperature and then shut off for 15-30 minutes. Once cold it starts and purrs.....

 

[MythX]

One of the first things I'd check, is the battery cables. Specifically, check for corrosion and proper connections (are they tight?).

I'm not speaking from Ford Explorer experience, just experience in general.