Rough Idle/Stall_Possible MAP, lots of codes.........its seized.

[jeckel7234]

2006 Explorer XLT ~130k mi, 4.0L

BLUF: While trying to figure out if there was a large vacuum leak or if the MAP sensor was messed up the motor seized up....How screwed is this motor?

Background
Good afternoon all,

I bought the explorer for son ~ 4 months ago while he was coming up on getting his learners permit. I have been driving it 1-2 times a week since we got it, with no issues; I also scanned all modules about a month after buying it and no codes were given. Low and behold, on the way to the DMV to take his test we start the explorer and it sounded like crap (rough/sporadic idle), so we shut it down and took my car to the DMV (he passed). Today we tried to figure out what the problem was.

The idle remains sporadic but low enough to occasionally stall out, also got a check engine light......with 13 PCM faults (below).

I then took vacuum off the manifold and was getting 15 inHg or less; based on this and the MAP faults and I used propane to search for large intake leaks but never found one.

I then attempted to restart the engine to pull live data from the MAP sensor and the motor would no longer turn over......guess i should have looked more into the P1336 code .........I then pulled the serpentine belt off and crawled under the truck with a 18" long ratchet to try and turn the crank but it would not budge.....sad day.

I havent pulled the valve covers off yet, but I'm guess the timing chain broke.

A few questions for the community:

1. Is this an interference motor?
2. What are the pistons made out of and how often are they damaged enough to require be replaced if this an interference motor.
3. Is replacing and hand lapping the valves a difficult job? Ive done this on Honda J35s before.
4. Any other thoughts?

Thanks all

 

[Rick]

Yes it is an interferance engine. Valves will contact pistons if timing chain breaks or goes out of time.
The pistons are aluminum. If you're lucky only the valves will be damaged not the pistons.
Here is a thread describing the timing chain replacement. Obviously you will have to go farther to remove and install new valves.

How to: - Timing chain replacement on a 2002 explorer 4.0 l

My wifes ford explorer 2002 of 100000 miles has a broke rear cartridge, so i got to pull the motor and pull the chains, i have some photos and videos, and i started the thead late so the stuff might be out of order.....but i do still need help the the chains, i quess im a little confuse about...

www.explorerforum.com

Best of luck.