Intermittent starting when hot

[Hbsocal]

1995 explorer 4.0 has intermittent starting issues , seems to be when engine is hot. We just got this vehicle for son to go to northern Arizona for college and he has to cross the desert in Cali, any ideas? 160000 miles on vehicle

 

[bobflood]

If it starts normally when cold, but is hard to start when hot, first thing to look at is the engine coolant temp (ECT) sensor. This tells the computer how hot the engine is; a warm engine needs less fuel to start than a cold engine. If ECT bad, computer thinks engine is cold and dumps in too much fuel, thus flooding engine and requiring more cranking. ECT usually in the thermostat housing and usually has two wires; temp guage sender just has one wire. Good luck.

 

[koda2000]

if you plan to replace the ECT sensor and have the black plastic thermostat housing there is a good chance it will crack and/or leak afterwards. check to see if there's a way to test the old ECT before removing it.

 

[Hbsocal]

I was reading and thinking the electronic ignition module migHt need replaced, has anyone replace this part before?

 

[Renegade27]

My 99 4.0 OHV had hard starting issues when the engine had been run and then shut off for 30 minutes then restarted hot. My problem was the idle air control valve (IAC) would heat soak and fail but work fine when cold. I had to double foot it to get it to idle (gas/brake) then after driving a few minutes it would idle normally. Some people have said you can take it out and clean it but that didnt work for me, I just replaced it.

 

[SoHK_alumni]

I was reading and thinking the electronic ignition module migHt need replaced, has anyone replace this part before?

There is a single ECU that runs the entire powertrain. After that, two ignition coils. Don't think your symptoms fit a failure of those components.

My 96 5.0 had very similar symptoms, turned out to be fuel pressure problem. Adding an in-line check valve cured the issue on mine.

Din't know why the start problem was only hot because the pressure faded anytime the engine was shut down.

Try doing a fuel pressure test and watch pressures after shutting down the enfine.