O/T: '92 Caravan charge temperature sensor

Tonight, on a cold start, it fired up on the 3rd try(didn't fire at all on first 2). Idled smoothly for about 5 minutes, then started running rough. This occurs as a slight miss and gradually worsens until the engine quits. Running time can be prolonged by moderately revving the engine. When it does quit, it will restart but still runs very poorly, and only for a few seconds.

We put this engine in this summer(engine is from a '91 New Yorker). Problems did not arise until fall, when temperatures dropped.

I noticed tonight that there's a sensor on the intake that's not plugged in. I can not find a plug in the wiring for this sensor. By the Haynes manual, this is the charge temperature sensor. What is the function of this? Does it read the temperature of the air entering the intake for the computer to adjust richness?

My best guess is that it is loading up with fuel. Does this make sense to y'all? Wouldn't an overfueling problem be less pronounced at cold start(when fuel needs to be richer) and get worse as the engine warms up(when fuel need to be leaner)? Or am I barking up the wrong tree?

Can someone explain the function of this sensor, just to make sure I am going in the right direction?

Suggestions and opinions are appreciated; I thank you for your time.

Happy Holidays!

Anthony

I checked for vacuum at the fuel pressure regulator, thinking a busted vac line, and don't recall any dampness.

As far as the scan tool, I couldn't agree more! lol I've suggested a couple times that he trailer it to town and have that done, but the idea hasn't sunk in yet.

Thank you,
Anthony

WHERE is the sensor.... intake manifold of the donor engine, or in the intake air ducting that has been with the van all along?

If the sensor is in the donor engine, and the original engine did NOT have one there, there obviously won't be a pigtail/connector in the van's harness for it, nor will the van's as-original 'puter be looking for it. Of course, also the original engine could have the sensor at a different location.

If you have access to a good scan tool, you can probably get a readout on what the 'puter thinks the coolant temperature is, as well as seeing if it is looking at the charge air temperature, and what it is seeing for a temperature there, to see if it makes sense.

Also, there are 2 water temperature sensors. One is on the end of the front head. This one operates the temp. guage. But there's another one, much larger, directly behind the thermostat. What's the function of this one?

Thanks,
Anthony

If you are still using the van's original 'puter, it will be looking for the exact same wiring and sensors as it left the factory with.

If the wiring has been "cobbled up", it would be a NIGHTMARE to trace every thing out to get it back to what the 'puter expects to see.

I sure wish he hadn't gotten rid of everything; it would be a whole lot easier if I had the other wiring to look at.

WHERE is the sensor.... intake manifold of the donor engine, or in the intake air ducting that has been with the van all along?

If the sensor is in the donor engine, and the original engine did NOT have one there, there obviously won't be a pigtail/connector in the van's harness for it, nor will the van's as-original 'puter be looking for it. Of course, also the original engine could have the sensor at a different location.

If you have access to a good scan tool, you can probably get a readout on what the 'puter thinks the coolant temperature is, as well as seeing if it is looking at the charge air temperature, and what it is seeing for a temperature there, to see if it makes sense.

Let's go Mountaineers,

Aaron