1998 Ford Explorer Stalls When I Turn on the Air Conditioner

[Metalface]

I will check the coil.

Good luck! Can't hurt. Tried finding similar threads with solutions, a lot went unanswered unfortunately. Lots of people had your problem however it seems. How has the fuel pressure at the rail been..? It can be on the low side -- should still start however -- if there is "some" pressure and still no start or it is cutting out, I'd check spark (or all of what is between the plugs and the PCM...) Check that you have spark all the time. If it starts to die, or if you can simulate the conditions in which it stalls perhaps in the driveway.. try to verify spark in that instance. I wonder if something is coming and going that isn't just fuel pressure, perhaps spark. That was my problem when it came to the coil. A long while after it was the Crankshaft Position Sensor -- but that was years later. Definitely unrelated. I think that part can be mostly ignored if it is clearly happening under a load via the AC and easily replicated.

 

[CynthiaK]

Good Morning!
I let my Explorer sit overnight with the battery cables disconnected.
I just went out and reconnected the battery and it started like normal with 32 pressure at the fuel rail.
It must have something to do with heat - perhaps the coolant temp sensor is to blame but the gauge never reads high and still no codes.

 

[CynthiaK]

Good luck! Can't hurt. Tried finding similar threads with solutions, a lot went unanswered unfortunately. Lots of people had your problem however it seems. How has the fuel pressure at the rail been..? It can be on the low side -- should still start however -- if there is "some" pressure and still no start or it is cutting out, I'd check spark (or all of what is between the plugs and the PCM...) Check that you have spark all the time. If it starts to die, or if you can simulate the conditions in which it stalls perhaps in the driveway.. try to verify spark in that instance. I wonder if something is coming and going that isn't just fuel pressure, perhaps spark. That was my problem when it came to the coil. A long while after it was the Crankshaft Position Sensor -- but that was years later. Definitely unrelated. I think that part can be mostly ignored if it is clearly happening under a load via the AC and easily replicated.

The pressure at the rail has always been around 30, except yesterday (daily temp was 33.5 C) when it was 0 and now this morning (23 C) it was 32 and the vehicle started. However, ambient air temp should not affect it.
I will have to check all the spark plugs.

 

[Metalface]

Fingers crossed this doesn't end up being an electrical gremlin issue and more of a "change one part and the whole system behaves" type of issue. When ambient temp/weather starts affecting stuff, makes you wonder if it's condensation reaching electrical contacts when it shouldn't be (such as in a PCM.)
At this point I'd definitely change the coolant temp sensor like others said and then whittle away at other possible issues one by one to see if it gets any better. That's really complicated I'm sorry you're having to deal with this :/

 

[Mbrooks420]

Good Morning!
I let my Explorer sit overnight with the battery cables disconnected.
I just went out and reconnected the battery and it started like normal with 32 pressure at the fuel rail.
It must have something to do with heat - perhaps the coolant temp sensor is to blame but the gauge never reads high and still no codes.

The coolant temp sensor the engine uses for fuel/air ratio is not the same as the one that feeds the dash gauge.

 

[C420sailor]

Stalls…won’t restart until it cools. Okay.

Give the ignition coil a good look over for cracks, as mentioned.

Does your code reader do live data? If so, bring it with you. When the truck dies, look at the RPM on the reader while you crank it. Should be at least 150 or so. If it reads zero, it’s your crank position sensor. They like to crap out when hot, then start working again when the truck cools off a bit.

The AC bit may be a coincidence, or indirectly related. Remember, running the AC heats things up much more rapidly under that hood.

 

[Metalface]

Stalls…won’t restart until it cools. Okay.

Give the ignition coil a good look over for cracks, as mentioned.

Does your code reader do live data? If so, bring it with you. When the truck dies, look at the RPM on the reader while you crank it. Should be at least 150 or so. If it reads zero, it’s your crank position sensor. They like to crap out when hot, then start working again when the truck cools off a bit.

The AC bit may be a coincidence, or indirectly related. Remember, running the AC heats things up much more rapidly under that hood.

A+++++ listen to this guy.

 

[CynthiaK]

The coolant temp sensor the engine uses for fuel/air ratio is not the same as the one that feeds the dash gauge.

Yes. The one that feeds the gauge is actually considered a switch while the other one is the coolant temp sensor.
I was just meaning that my vehicle never has heating issues.

 

[CynthiaK]

Stalls…won’t restart until it cools. Okay.

Give the ignition coil a good look over for cracks, as mentioned.

Does your code reader do live data? If so, bring it with you. When the truck dies, look at the RPM on the reader while you crank it. Should be at least 150 or so. If it reads zero, it’s your crank position sensor. They like to crap out when hot, then start working again when the truck cools off a bit.

The AC bit may be a coincidence, or indirectly related. Remember, running the AC heats things up much more rapidly under that hood.

I did have a look at the coil, but did not take it out. I will do that.
My reader does not do live data but I think I have to go and buy one to check for the RPM when it dies.

This morning:
I unplugged the AC and started the vehicle - it ran fine - 32 at the fuel rail.
Plugged in the AC but did not turn the AC on - it ran fine - 32 at the fuel rail.
I turned the AC on to Normal (not Max) and the fuel at the rail dropped to 20 and the truck started to chug so I shut it off before it stalled.
It was not on long enough to build condensation. The AC was not whining but it was kicking in and out continuously for the few minutes that it was on.

 

[Mbrooks420]

Yes. The one that feeds the gauge is actually considered a switch while the other one is the coolant temp sensor.
I was just meaning that my vehicle never has heating issues.

Yeah, that’s not correct. Both are analog sensors that send a range value.

You’re thinking of the oil pressure.

Heating issues have absolutely nothing to do with a coolant sensor messing up the AF ratio and preventing the vehicle from starting.

 

[CynthiaK]

Yeah, that’s not correct. Both are analog sensors that send a range value.

You’re thinking of the oil pressure.

Heating issues have absolutely nothing to do with a coolant sensor messing up the AF ratio and preventing the vehicle from starting.

I was told that was the difference between the two. I guess the person that told me was wrong...

 

[donalds]

I was told that was the difference between the two. I guess the person that told me was wrong...

Indeed they were

 

[UtahX]

Had similar issues, it was the fuel pump.

 

[CynthiaK]

I had the pump replace a few years ago but maybe it is bad again...

If it was the cranskshaft position sensor, would I not get a code P0335 or P0336 or both? Or can it still fail and no code is presented?

I just drove around (and around and around) my neighbourhood for 1 hour with no problems at all. Pulled in to shut it off and when I put it into reverse, it stalled again!!!

 

[C420sailor]

You can have no code.

But it generally doesn’t coincide with things that put load on the engine (like dropping into gear) or any event for that matter.

The IAC should be compensating for the load. And the mechanical idle stop should be set low, but also high enough that the truck can idle with AC on and in gear without stalling, with the IAC disconnected or failed. It won’t idle well like that (low) but it’ll keep running

 

[UtahX]

I had the pump replace a few years ago but maybe it is bad again...

If it was the cranskshaft position sensor, would I not get a code P0335 or P0336 or both? Or can it still fail and no code is presented?

I just drove around (and around and around) my neighbourhood for 1 hour with no problems at all. Pulled in to shut it off and when I put it into reverse, it stalled again!!!

I was not getting the codes as well. It went on for years, then someone said try the fuel pump. I also replaced the intake manifold gasket, it was the first thing I did, but it did not help at all.

 

[CynthiaK]

I was not getting the codes as well. It went on for years, then someone said try the fuel pump. I also replaced the intake manifold gasket, it was the first thing I did, but it did not help at all

Is there a way to test the fuel pump other than pressure at the rail?

 

[UtahX]

Is there a way to test the fuel pump other than pressure at the rail?

I'm not a mechanic, sorry.

 

[Turdle]

Next time it will not start cycle the key on and off 4 times then try starting.

I suspect fuel pump, fuel pump relay, pcm relay in that order.

 

[CynthiaK]

Would a failed O2 sensor cause these issues?