Non-Stop Cranking until battery dies

[AM0608]

I turned on my 2000 Expedition 4.6L this morning and it started fine like usual, then I put it in reverse to get out of my driveway and it stalled. I put it into park and tried yet again to start it, it made the cranking noise to start but never actually started and just kept cranking even if I turned the key back, removed the key, etc. I had to disconnect the battery to get it to stop. I posted about this problem in a Facebook Expedition group and it was suggested that it might be the ignition switch or to try using different keys. The key fix didn't work so I went to get the ignition switch and replaced it. I started it about 5 times in a row to test it and it was fine again in my driveway. I posted a thanks and thought that was it. A little later I needed to go run errands so I started it and it was fine even when reversing unlike in the morning. I got to a main intersection not even 5 minutes away from my house and it died while I was stopped and going to make a turn once the light turned green. I started it again and it just started doing the cranking again (the theft light went on as well). It kept doing that for a minute or so then I finally got it to start but as soon as I put it in gear to try to move it it stalled again. It then did the cranking non-stop once again until the battery died. I got towed home and charged the battery (which the charger's overload light came on and the battery was warm). It wouldn't start after charging it so we jumped it and for the first few times it would start but as soon as you remove the jumper cables it would stall after about 30 seconds of it in gear. Tried testing it by unlocking with the unlock buttons on the vehicle and on the fob to see if that helped but didn't seem to, once the battery had more power it would just start the non-stop cranking again. Anyone know what this is (I'm assuming some kind of electrical issue) and/or how to test/fix the problem so we can be reassured of the reliability of it when we want to take it out again? Thanks.

 

[american steel]

I have a feeling your starter regulator might be a cause or the PATS ******** is creating the issue.
my 02 did this years ago and I replaced the starter reg it fixed the problem.
if your PATS light is flashing constantly there's a problem with that. make sure your key is tuned to the factory computer module.

 

[stamp11127]

One of two things may be happening:
1) Starter solenoid/relay has failed leaving the high current contacts "closed" which allows current to the starter motor. Will run until the circuit opens or starter burns up.
2) The control side of the starter relay is staying powered which is keeping the high current contacts closed. This would be a failure on the ignition switch side of the circuit.

Easy to tell with a test light or meter.

 

[EightIsEnough]

Sounds like something Col. Hogan would pull. Sorry this is not a helpful post, but I happened to be watching Hogan's Heroes when the post came up.

 

[AM0608]

Ok just a update. I changed the starter and it starts fine now but as soon as I put it in any gear it stalls and the theft light starts flashing. If I hit the unlock button on the fob it starts fine again then stalls in gear again with the theft light on. What could this be? I was told it may be the key but it has been working fine before all this.

 

[stamp11127]

The key is out of the picture once the ecm validates the key is valid and allows the engine to start.
How fast does the theft light flash once you put it in gear and it dies?
What electrical test equipment do you have available? Meter, code reader etc

 

[AM0608]

I have a multi-meter and a code reader (scanned it and no codes showing up), and the theft light was flashing fast. Just started it seemed fine, not doing it now but still don't trust driving it until I figure out what it is or was.

 

[stamp11127]

You may want to check the connections to the pcm. Also a vd test on the grounds. If your code reader receives power through the obd port you can use the reader to see if the pcm is loosing power. If it is it will power down or lose connection to the pcm.

 

[AM0608]

connections to the pcm are good code reader isn't showing any codes and I got a new key cut from the dealer and its still doing the same thing...

 

[stamp11127]

By "same thing" you mean the stalling issue?

If so, does the code reader loose connection with the pcm when you put it in gear? Does the trans make it into gear or does it stall prior?

What is your level of wrench turning/knuckle busting?

 

[AM0608]

Yes same thing as in stalling. It gets into gear and a few seconds later it stalls if I leave it in park it stalls after about 2-3 mins. I just checked the scanner and waited until it stalled and go this msg "unable to establish a link with the vehicle Verify the connection at the DLC". I am pretty good at turning a wrench.

 

[stamp11127]

I will look at the wiring diagrams tonight and give you the wires to check. We will look to see if the power to the pcm is dropping out or if there is an internal problem.