2017 Explorer XLT, V6, 3.5L, Non turbo, no start, compression issues

[Happster]

So this is a new one for me. My wife's motor in her 2017 Exploder XLT AWD, V6, 3.5L, non-ecoboost, non-turbo, geeked out and lost all it's antifreeze into the oil in just a couple hours. 180k miles, wasn't worth even diagnosing why. Likely a cracked head or severely blown head gasket on bank 1. Compression sucked on that bank.

So I found a new-to-me plug and play motor with about 50k miles. Looked clean as hell. Took the lower intake off and the valves looked prestine. (Wish i turned it over by hand and watched the valves operate.) Plugs that came out of it looked fabulous too. Finished enough of the install to run a compression test in case i was sold junk and, starting on bank 2 cylinder 4, left to right, I got 120 lbs. (cylinder 4), 60 (5) and 60 (6). Bank 1 I got all 60s across the board. So I went back to cylinder 4, and this time I got 60 from that cylinder too. Motor has been cold abd sitting for months. Thinking I toasted my compression tester I bought a new one. With the new tester i got all 30s across the board. Anyone have any idea WT absolute F could possibly explain all of this? I finished the install to see if it would start and it didn't. Shot some starter fluid down her throat and she didn't even queef.

I'll run compressed air into each jug at TDC and see if I can trace the leak, and I'll also confirm spark and fuel pressure. I'll plug her into my Autel to see if there are any hints there. But damn this has me befuddled. What are the odds of both heads being cracked, or head gaskets blown out? Im thinking not too damn likely. Any thoughts, and/or other tests to run?

Thanks up front.

 

[peterk9]

Could the initial problem have been a leaking water pump?

Peter

 

[Happster]

Could the initial problem have been a leaking water pump?

Looks like that IS a possibility. Thanks for that, might be able to more easily refurbish the old one and recoup some costs.

 

[Happster]

Ok, so I figured out what I was doing wrong with the compression test. I wasn't cranking it long enough. Wow do you really have to crank this thing to get a full reading. Compression is fine.

Still no start. I'm getting a PO6E9 DTC, which means the PCM is sending power and ground to the starter but not sensing crank rotations. I swapped out the crank sensor from the old motor and no change. I have the bumper cover off the car, but I can't imagine unplugged headlights and bumper sensors would create a no start condition. Thoughts appreciated on tests to try, possible causes.

 

[Happster]

Well, for those of you as inexperienced as me with flywheel side crankshaft position sensors, I may as well swallow my pride and tell you that the problem was that I missed installing the crankshaft sensor pickup ring on the rear of the crankshaft. lol. My buddy from a Ford dealer asked me if I had the old motor and asked me to look carefully at the backside of the crankshaft. Sure enough, there it was, it popped right off. So back out she came, cracked off the tranny, installed the ring and put her back in. Running great.

Then I was getting a random misfire. The engine would go into limp mode for maybe 20 seconds, CEL would flash, then it would run fine again and stop flashing. Rinse, repeat. I would pull P0300 (random misfire), p0302 (cylinder 2 misfire) and P0306 (cylinder 6 misfire) DTCs. That's when I learned about the crank sensor reset procedure that needs to be done any time you monkey with the crank sensor. Was able to do it with my Autel and she's purring like a kitten!