Solved 1992 Explorer wont start once it is warm

[allmyEXes]

I have a stock 1992 ford explorer 4x4 with a 4.0 liter engine and automatic transmission. It has 148,000 miles on it. It has been sitting 6 years with an empty and very dry fuel tank. The fuel in it now is 2 days old. I don't doubt that some parts made from rubber or electronic parts could have gone bad or are going bad from sitting several years
Here is what it has been or not doing.
In the morning the engine starts when cold every time without fail. Once the car is at operating temp and turned off, it has a slim chance of starting up again. The car cranks fine. starter, solenoid, battery and all that work fine. It peters out once I let off the ignition and the engine tries to take off on its own but it just can't. It sounds like it is going to start every time as in it turns over, but just sputters and nothing. After waiting until the next morning it will start. Once it decides it wants to run, it idles very roughly at first only. I give it some throttle to keep it going and it will eventually run. Once the engine gets going again it runs and idles fine. It absolutely runs 100%.
Any suggestions would be appreciated, but keep in mind the car runs fine once it has been started. So it has to be independent of the engine running mechanics and is temperature sensitive.

 

[Fix4Dirt]

coolant temp sensor? iac heat soaking? not sure

 

[Rick]

My guess is that crud is falling away from the filter sock on your fuel pickup after sitting overnight and then getting sucked back into it when the engine is running. I wouldn't doubt if it became nearly solid with crap after sitting for so long. They say fuel goes bad quicker when the tank is low due to increased oxidation.

 

[allmyEXes]

I questioned the IAC for a moment. The tank has been sitting empty and clean from the time it was parked because of the transmission going out.
i'm wondering if it is a fuel pressure issue.

 

[donalds]

Sounds to me like the temp sensor

 

[allmyEXes]

Why would a temp sensor make it not start?

 

[allmyEXes]

@donalds I believe the '92 only has one temperature sender/sensor and my temperature gauge is operating properly.

 

[Fix4Dirt]

Why would a temp sensor make it not start?

if it reads hot, it may start in a open (?) loop fueling system, and it may be optimized for it being hot/overheating/cold, and the same fueling etc does not apply to the other conditions

 

[allmyEXes]

@Fix4Dirt This is on my 1992 gen 1 4.0 ohv powered truck. It has only one temp sending unit and the gauge is functioning properly. My '97s have two sensors. One for the gauge and one that sends a signal to the PCM.

 

[Fix4Dirt]

@Fix4Dirt This is on my 1992 gen 1 4.0 ohv powered truck. It has only one temp sending unit and the gauge is functioning properly. My '97s have two sensors. One for the gauge and one that sends a signal to the PCM.

oh ok! not too familiar w th 1st gen, so that makes sense! yeah thats how my sohc is, so i assumed ohv was same, but i get it now other than that, i can oly think of maybe fuel pressure when warm? but then it shouldstumble when its running... iac? i wonder if its an issue after itheat soaks, that could explain the initial hesitation and neeed to give it gas

 

[allmyEXes]

I guess @donalds got the message that i am talking about 1st gen?...

 

[donalds]

You are correct 1 sensor

I'd still test it tho even a few Ω off will cause problems

Sorry would have responded sooner I've been busy

 

[410Fortune]

Check fuel pressure when cold and then warm/no start see if it drops off

Usually this is a weak fuel pump

 

[Fix4Dirt]

Check fuel pressure when cold and then warm/no start see if it drops off

Usually this is a weak fuel pump

what happens if you prime the fuel pump a few times?

 

[allmyEXes]

@Fix4Dirt I can't tell if it is starving for fuel or flooding out. As Jamie said, I'm gonna check fuel pressure cold the check it after it is warm and won't start. At least there are only 3 components associated with the fuel delivery system. I do have access through the floor to the pump. Fuel filter is easy enough to get to on the lift. @donalds Do you know the acceptable ohms range for the basic ford temperature sending unit for a gauge?

 

[donalds]

@Fix4Dirt I can't tell if it is starving for fuel or flooding out. As Jamie said, I'm gonna check fuel pressure cold the check it after it is warm and won't start. At least there are only 3 components associated with the fuel delivery system. I do have access through the floor to the pump. Fuel filter is easy enough to get to on the lift. @donalds Do you know the acceptable ohms range for the basic ford temperature sending unit for a gauge?

Ford engine coolant temperature sensor (ECT) resistance chart.

This chart is for troubleshooting the ECT, and ACT sensor at different temperature ranges.

www.explorerforum.com

 

[allmyEXes]

This afternoon after the '92 ohv had not been started for 25 hours I attached the Fuel pressure gauge to the Schrader valve on the fuel rail. When the key was turned to the run position the pressure went up to 20 psi before the fuel pump stopped pumping. Turned the key off and back on and the reading went up to 41 #s. Then we started the truck. The pressure immediately settled in to 32 to 34 depending on the RPMs and stayed steady. After the engine warmed up it was shut down and started back up and the pressure was 32 to 34. The truck started 2 more times before we quit.
Another issue is a steady misfire. I will change the spark plugs which I know are 15 to 18 years old and also going to buy some kind of fuel injection cleaner to add to the 3 gallons of new fuel in the tank. When the truck got parked 6 years ago it was run out of gas and then the fuel pump/sending unit was removed. The tank was dry and clean and I assume that the injectors would have been empty, but don't know. Also one of the next things to do will be to clean the IAC and measure the ohms of the TPS while it is unplugged. If there is a check engine light it is not illuminating and the way it runs it should be on. Someone may have removed the bulb 20+ years ago.

 

[ChildIdenticant]

If there is a check engine light it is not illuminating

CEL should be on briefly at every start , regardless of error condition.

 

[allmyEXes]

@ChildIdenticant Thanks. I'll watch for it again mid-day morning when I start back on it.

 

[Josh P]

@Fix4Dirt This is on my 1992 gen 1 4.0 ohv powered truck. It has only one temp sending unit and the gauge is functioning properly. My '97s have two sensors. One for the gauge and one that sends a signal to the PCM.

1st gen has a temp sending unit and a sensor for the ecm.