Engine sometimes wont start when hot?

[Raxkalon]

I have been going thru this for 2 months, I have changed air filter, ignition coil, plugs and wires, massive air flow sensor, and fuel filter.

Problem is the only time it doesnt start is after its been driven for 30 mins to an hour, so everytime i replace something I dont know if its fixed till it does it again.

When it doesnt start it requires a (cooling off period?) of up to 2 hours and then it cranks fine. I have had it on 2 diagnostic machines according to the mechanics one said mass air flow sensor other said starter (which i completely dismissed). Starter turns fine it engine just wont hit.

Vehicle is 94 ford explorer xlt (wife is driving so I need to fix it badly!

Thanx in advance

 

[MrShorty]

Did the mechanics have it when it wouldn't start? I don't think a bad MAF will cause a no start because the computer has a backup algorithm that will allow it to run without the MAF. Have you been able to isolate the no start to a lack of fuel or spark?

 

[Raxkalon]

No, it always starts when someone else is looking at it.
I just tried the fuel relay wiggle and that didnt seem to help either.

After all the stuff ive tried it will almost always cranks now, but spits and sputters till it goes dead and after a few tries wont crank at all.

So i would guess its fuel related or maybe timing I am sure I have spark

Thanx for reply!

 

[slow-demon]

Looks like its a fuel pump problem. I've seen quite a few cars and trucks with similar concerns. If you hook up a fuel pressure gauge you can see if in fact you are loosing fuel pressure. Replace the Fuel Pump....

 

[Nicaraguense]

Aint that the daingdest thang

Cars always know when mechanics are in or around them. They just seem to have this sixth sence about them. I'm not even a mechanic (no where near it) I just work at Auto Zone and can give my free opinions / smart alec comments and I have trouble getting cars to act up when I am in them. (More that check engine light that we check for fee (just some of the common codes we have a OBD II sensor (we do that for free by the way) but when it is dealer specific, we can't even tell you what it is.

 

[Alto]

How is your Temperature? Could be your radiator or cooling system!

The temerature of the radiator fluid will rise after the truck is shut off. Happened to my car all the time. Even faster when I had A/C going.

 

[Raxkalon]

Thanx for the replies will check the fuel pressure today!

Unless my temp gauge quit working I dont think its too hot, but i recently purchased, so I am not gonna rule it out.

Had also read something about the crankshaft position sensor and the throttle position sensor, but not sure if those would only apply when hot, tapped on both to no avail.

 

[xemite]

94 Ford Explorer Stalling

I have a 94 Ford Explorer w/138,000 miles and it is doing the exact same thing. Starts cold...runs until warm, but when I turn it off and try and turn it back on it acts like it is not getting fuel. I usually will have to wait 15 min. to an hour and then it starts and runs perfectly.

I have replaced the MAF, DPFE, and cleaned the IAC. The symptoms have continued, so today I bought an Actron Scanner for 30 bucks from Auto Zone. It gave me the following codes:

33: EGR Pressure
543: Open Circuit to Fuel Pump; between battery and PCM

Tomorrow, I will clean and replace EGR components, check the Fuel Relay and check the wiring to the fuel pump and PCM. I'll keep you updated. Let me know if you find anything out.

Thanks.

Jon

 

[BeachTech]

I had a 1986 Ford Full-size Bronco with the 5.0 V8. It sounds like your car is having the same problem I had on the Bronco. Basically, cold starts (engine not running for 2 hours) were no problem. However, if you had to stop and grab something at the store, you had to wait over 30 minutes before it would start again.

It became worst later on. You may get it to start after that stop at the store, but the strangest thing would happen. I would be driving down the freeway and suddenly the RPM gauge would drop like a rock to 0, then jump back up to 1800, and would cycle a random number of times like this in just a few seconds. (The engine would keep turning while this was happening because the torque convert was in the lock position since it was over 55MPH).

I talked to so many people about this. Then one day I am talking to one of my buddies who builds ski boats. He had experience with the 5.0 in boats. He told me there was a problem with the PIP (Hall Effect) Sensor (I think that is what it is called) that is inside the distributor. It takes the place of points (if you remember what those are). I had to remove the distributor, have the gear removed at the bottom, remove the shaft, and then I could remove the PIP sensor. I replaced it with a NON-FORD part at his recommendation. The Bronco ran for about 10 years after that with no further problems like this.

 

[410Fortune]

FUEL PUMP RELAY

ALSO

THE COMPUTER ITSELF

I didnt read the whole thread, but from what you describe both of these I have seen cause this problem

Also the starter itself (solenoid in starter) if it doenst even crank......