So I have a 00 Expedition, the other day my girl went to the store, called and said it wouldn't start, I showed up, turned it over and it started. Followed her home, it died at a light, but started back up. I checked for codes, and it had none. Few hours later I tried to start it and it fired up. The next morning she went to go to work, it didn't start, just cranked over, she called a cab, tried to start it again and it fired up. When she got home from work, we jumped in it to get gas and repair a low tire, after gassing up, I went to start it, and all it would do is turn over. About 10/15 mins later it fired up, left it running until we got home. Today after I got off work, replaced the cam sensor, started up, shut it off, tried to start it up, and would not start. Thought maybe the fuel pump was going out,(that I replaced about 4 years ago) sprayed some starting fluid, still no start. Pushed the gas pedal down a little like you would if it was flooded, and it started turning over like a flooded and then started. Shut it off and tried to start...yep didn't start, just cranked. I'm wondering if it might be the PCM? I did try disconnecting the battery for 30 mins, and that didn't work. Any suggestions would be appreciated.

 

I see that you replaced the fuel pump a few years ago, but can you hear the fuel pump run with key on?
Intermittent fuel pump relay failure?

Just a crazy guess, but could the chip in your Key crapping the bed?
Does your Expedition have a Security light in the instrument cluster? I'd look to see if that light is going out when you're cranking it over.

 

Do you have a fuel pressure gauge you can connect to the fuel rail schrader valve and see what kind of fuel pressure you're getting to the fuel rail ? Should be 35-45 psi . Did you say you had a code reader ? Any DTC codes stored in the computer?

 

No I dont have a fuel pressure guage...
no codes...
yes it has the theft light in the dash..

I believe the key is good, I did dissconect the battery for 30 mins, and also tried the manual door lock with the key.
Funny thing I just got home from work,, went out and it fired up..noticed the temp Guage bounced a little then just went flat.. also it was idling at about 2K rpms, it went down to 1200, when I gas it, it seems to hesitate coming down,, sometimes sticks anywhere from 1500 to 2K. So I pinched the hose to the IAC valve and the rpms dropped. So I shut it off and tried to restart it, no fire. Just watched a video on how to test the IAC, gunna try that and see what happens. Thx for the responses.

 

That gauge needle bouncing like that seems like an indication of water/corrosion in the fuses/electronics under the dashboard.
Have you had any water leaks around the windshield? Is your drivers side carpet wet?

 

no leaks, carpet dry

 

Just got off the phone with a mechanic, he suggested replacing the crankshaft sensor. Wouldn't it throw a code if that was the problem?

 

Probably not. When the PCM doesn’t see a crank signal, it just thinks your not cranking the engine.
When you turn the ignition key to the on position, the CEL lamp should illuminate.
When you turn the key to the crank position, if the PCM sees the CKP sensor signal it will turn the CEL off.
If the CEL stays illuminated while cranking, the PCM hasn’t seen the CKP sensor signal.

 

Update, picked up a crank sensor this morning, started truck to take to my dad's to work on(4blocks away), and the oil light, temp light, and check engine light were all on. Ran the codes, and got P1504, and P1289. Head temp sensor, and Idle Control Valve. Replaced both, and it now starts every time. Temp gauge is also working properly. I believe it was IAC. But it's fixed...for now. Thank you to all that gave input. I really appreciate it.

 

So my girl mentioned to me that it seems to be idling high when it starts but does come down. She said it's at 2K rpms, but does drop down after a min. Is that normal after replacing the IAC?

 

For a cold start when it's really cold out, it's normal for my Navigator to scream for less than a minute at about 1500-1800 RPM. And then drop to the normal ~800 RPM.
That's normal.

But I'd double-check all the vacuum lines in the areas under the hood that you've been messing with. You might have pulled or broke a vacuum hose.
Fords use a hard plastic tube for vacuum that break very easily. That's one reason for a high idle.

Also, I assume you used a chinese IAC? I'm not saying it is or will cause you further issues, but yeah, it's a possibility that your Ford computer doesn't speak chinese. The parts aren't made to "spec," and computers are fussy about sending and receiving proper signals. That's another reason for a high idle.

I hope you saved your original IAC just in case you need to put it back in.