Expert Challenge!! - '07 Explorer will not start

[347Mustang]

Hello friends and resident experts. I have a frustrating issue on my hands and a good challenge for the experts among you, as this seems to have stumped everyone I know including my mechanic.

The vehicle

2007 Ford Explorer Sport Trac, 4.6L V8 AWD, Limited

The Issue

The truck will not start. Turn the key and nothing happens.

All accessories appear to be working with key on (i.e. windows, air, radio, etc.) EXCEPT the instrument panel which has absolutely no lights or activity in response to the key being turned on or an attempt to start the engine.

Battery is new, has been tested, and is in 100% working order. Absolutely no issues there.

Checked all fuses, both interior and under hood. No issues there.

Circumstances that may or may not be relevant to diagnosis

The truck sat for several days (3) while we were away.

My wife broke the vanity mirror so the little light stays on at all times (been this way for over a year).

The dual zone air conditioning has been intermittantly acting up (blowing hot on one side, cold on the other).


I need help folks. I fear a towing and very large bill from Ford on the horizon.

Thanks!!

 

[347Mustang]

Update:

I left the battery disconnected overnight, hoping that clearing out the computer memory would help. It did.... sort of...

After reconnecting the battery, the instrumentation lights worked and the truck started.

Seemed like everything was working fine. Drove it around for a while, shut it off and started it a few times... no issues. Was ready to call the issue over, when the truck began to buck and shimmy a bit.

If you keep the throttle light or medium, seems to run fine. If you throttle it, it runs poorly.

May be misfiring in one of the cylinders, but not throwing any codes or anything.

Theory

I recently replaced one of the coil packs to address misfiring and an error code that was being thrown.

Seemed like that fixed the issue.

However, I am assembling a theory here... could the injector actually be bad?

Follow me here, if an injector failed (perhaps stuck) could it create a voltage drain? if so, could the smart junction have sensed the drain of that stuck injector while it sat, and shutdown the power to that system in an attempt to save the battery? Thereby causing the starting issues which resolved after I cleared the memory?

Thoughts?

 

[FIND]

A stuck injector wouldn't cause a voltage drain. They are basically just a little solenoid, a linear motor, that when you electrify a coil, it causes the solenoid to open which lets pressurized fuel spray. When you remove voltage the injector (should) close. But at any time, you can apply current to the injector, there is nothing in it that will break a circuit.

I don't know what to say about your problem... It would take more information to make a meaningful diagnosis. But, given your issues, I would suggest a short or ground problem would be a good place to start looking unless something else comes up to suggest where else to look. I would also unhook your MAF and see if that has any impact on your issues.

Also, if anything would have troubled your smart junction, I would think it would be that vanity light. Try disconnecting it and see if that has an effect on your issues.

 

[Lbarb26]

Did you ever find a solution? We are having the same exact problem. But wont start at all

 

[347Mustang]

Issue Identified Problem Solved!!!

Yes, actually we did figure out the issue.

There is a technical service bulletin which decribed the issue to the letter.

The TSB outlines a known issue with the instrumentation cluster failing intermittenly.

Required a replacement instrument cluster and standard transfer of programming from old cluster to new.

Ford does not make new clusters, your dealer will have to order a rebuilt one from a 3rd party company contracted by ford to make the repairs.

The new cluster was $275, and the programming was $100 (non-dealership pricing).

$400 all in for the repair. Not cheap, obviously. But completely resolved the issue.

By the way, there is a steep core charge ($400) for the cluster which you will not be able to get back until you return the old one to the dealership. Since you need to download info out of teh old one and upload it into the new one, you'll need to float the core charge for a day or so until they've done everything (applicable only if you have someone other than the dealership do the work, but worth mentioning).

Here is a link to the TSB:


http://ww2.justanswer.com/uploads/crackenzag1/2009-11-04_134128_sport_trac.pdf


Hope this is helpful. Finding this bulletin was not easy, and I came across a lot of folks with the same issue on various forums looking for answers. So I really hope this makes it around to those that need it.

Good luck!