04 4.0 V6 died and won't restart.

[jchesher22]

Hi, new to the site, thanks in advance for any help! My girlfriend has an 04 explorer 4.0 V6. She was backing out of the drive way the other day and the car stalled on her. When she went to restart, it just clicked and would not turn over (cold night, bad battery fyi). Next day I threw a charger on it, and it would turn over, but not start. I threw a spark tester on a plug and it's lighting up when the engine turns over. I wasn't sure how to check fuel pressure because there was no schrader valve, but I feel confident it's getting fuel because the plugs are wet from trying to start so many times check inertia switch just in case. Pulled codes and it had a p0174 (lean bank 2). Cleaned maf, nothing, tried with it unplugged, nothing. I see no huge vacuum leaks or anything. I kind of think that code is not the problem. Checked compression, that's good. I'm getting air out the tail pipe so I don't think the cat is plugged. I checked the cam shaft position sensor plug for continuity, good. I checked the ohms with sensor removed, was getting .45 @ 20k setting. And it would jump if I touched the sensor to metal. I removed the fuel pump fuse thinking maybe it was flooding and tried to see if it would pop off a couple times, but no luck. The tach moves when I try to turn it over, so I'm guess the crank sensor is good. I'm really not sure what else I could check...


On curious thing was that her spare key won't turn the motor over. U can turn the vehicle on, but not turn the motor over. She swears that she used that same key earlier in the day, to start and drive the car, before it died. When I put it in and turn it on, the red light on the dash flashes quickly, but the motor won't turn over. The other key turns the motor over just fine and does not cause the red light on the dash to blink rapidly. Could I be dealing with some sort of anti-theft issue?? I have no idea why that key would work the day before, but not the next, other than the fact that I cleared the code when I pulled it on the OBD2 scanner.


I'm by no means a mechanic, I've just tried everything I can think of, along with several suggestions from online forums. If anyone has any other advice or checks I can do, it would be greatly appreciated! Thanks

 

[Mbrooks420]

It’s not an issue with the anti theft with the key that turns it over.

Did the motor ever rattle when started cold? It’s possible it’s jumped time, if so.

 

[jchesher22]

She said she heard nothing, but I've wondered the same thing. Anyway to check that with out tearing things down?

Thanks for the reply! Any idea why the other key would have stopped working?

 

[Mbrooks420]

Thumb compression test. If it’s jumped time, or broke a chain there’s likely at least one cylinder with little or no compression

Not definitive, but a dead cylinder is certainly a terrible sign.

 

[donalds]

! Any idea why the other key would have stopped working

Dropping them on the table all the time

 

[Mbrooks420]

Some aftermarket keys have batteries and are clones of another key. If they don’t look the same this could be the issue with the second key.

 

[jchesher22]

Thumb compression test. If it’s jumped time, or broke a chain there’s likely at least one cylinder with little or no compression

Not definitive, but a dead cylinder is certainly a terrible sign.

I've got a compression tester. What's an acceptable range?

 

[Alex from GA]

Over 100 lbs

 

[Mbrooks420]

Ideal Compression SOHC See the chart in there by Donalds

 

[TechGuru]

 

[jchesher22]

Thanks for all the input, guys!!

Update, I went to check compression today. I hit the key and I heard it pop off a time or two! (I had 150ish psi on #6 btw) so I quickly threw the plug back in and hit the key again. It struggled to start, but once it did, it ran like a top! Can't believe it...

The day it happened, and the two days I spent troubleshooting afterward were rainy pretty much all day. I know damp conditions can cause havoc on ignition systems, could it maybe be the coil pack? I threw a plug tester light on and was getting a blinking light a few days ago, so I assume I had soark, but could it maybe have been misfiring to the wrong cylinder? Or just producing a very weak spark? It had been two days since I messed with it, both of which were dry. It actually got cold and well bellow freezing too, so I'm wondering if that dry air cured the issue?

Or am I crazy?

Is there a way I can check the coil pack??

I appreciate any input you guys could provide and thanks for the previous input!

 

[Mbrooks420]

Next time you do a compression test you should have the throttle all the way open.