Hot restart difficulties

[YBNormL]

My Explorer has been acting very strange this last week. The first start of the day, everything is fine. I stop to gas up or nip into a convienience store, and when I go to restart the engine, it just cranks and cranks. I have to put my foot full on the gas to get it to start up.

When the engine does this difficult restart, it typically is prone to stalling when I try to move from a full stop. It can cough if I'm already moving, and have to feather the throttle. The RPMs drop to about 400 for about 1 second. I think that the auto trans is keeping the engine rotating, hence why it doesn't die.

I've used a code scanner and I get a code 54 (Intake Air Charge sensor failure), and for the first time today, I got a code 14 (PIP circuit failure). The Intake Air Temp sensor was replaced 2 weeks ago, and it keeps apearing in my code scans. I'm still tracing the wiring, but havn't found the cause yet.

Does anyone have an idea on what is causing difficulties with hot restarts, and how I can make this code 14 go away?

Thanks

James

 

[Opera House]

First things first

Your code indicates the ait temp sensor is open or has a bad connection. At 50 degrees F it should be about 60K ohms. This drops to about 16K at 100F. With sensor disconnected there should be about 5V on the computer side connector. Since you replaced this, I suspect a wiring problem that is affecting both sensors. Try unplugging the computer connector and then plugging it back in. Later engines have an engine bulkhead connector and this might also have this. Most likely wiring problem, if not maybe water has been dropping on computer. Any windshield leaks?

 

[YBNormL]

I checked for a bad electrical connection yesterday by unplugging the pigtail to the sensor, turning the key to the on position, and checked the voltage at the pigtail. I saw a pretty constant 4.6V (keep in mind, the engine is not running). I was a little concerned about the voltage thinking that it should be 12V.

I then wiggled the pigtail with the voltmeter still attached. No matter if I pulled, pushed, or twisted the pigtail, I always got the same 4.6V reading. And this was done as soon as I got home, with the engine still at normal operating temperature.

The windsheild leak possibility is interesting. I haven't considered it before. We're having a good bit of winter right now, snow on the roads and colder temperatures. Maybe the windsheild washer fluid is finding a way in. I'll have a look at the computer and let you know.

Thanks

James