I have a 2000 250 with 198000 miles on it. About six months ago I went out to start it after it sat overnight and it did nothing the truck was running perfect prior... long story short I was told the engine would have to be rebuilt but as we were getting ready to pull the engine we realized that the ac compressor was so locked up it was preventing the engine from turning. both my mechanic and i were shocked that the engine didn't have enough crank to turn with the ac compressor locked up, we replaced the ac compressor and truck ran fine for about 4 months. about 2 months ago it just decided to start and not start whenever it wants. the only pattern I can figure out is that after it sits for awhile, couple of hours or over night, it starts just fine, no problem at all. but sometimes when i drive it and run into a store and come back out it won't start or it's a delayed start meaning it cranks for about 5 seconds and then starts. the most recent was when i drove it about 30 miles, shut it down and ran into a store for about 20 minutes, came back out and nothing... not even a crank. i tried to start it about every ten minutes and still nothing, after about the sixth time, about an hour later it cranked for about 5 seconds and then started up fine. i can't figure out what is wrong. sometimes it cranks for a little bit and then starts, sometimes it doesn't crank at all. luckily i've never got stranded because it ends up starting after i let it sit for a bit. i've replaced the battery connections, new battery, new starter, new spark plugs, oil, fuel filter, new ac compressor and cleaned k&n air filter. does anyone have a clue what could cause this or what i could do to narrow it down. and by the way it's not throwing any codes.

 

Have you tried pushing down on the gas pedal 1/2 to 1 inch and crank?

 

i've never done that because when it cranks it usually starts after about 5 seconds, and when it doesn't crank its nothing. i will try that next time... i thought initially about the fuel filter being dirty so i changed it... i thought if it was a fuel pressure issue it wouldn't be intermittent and it would be the oppposite... start fine after being shut down for only a little bit and not start after sitting for awhile... maybe i'm way off????

 

If the IAC (Idle Air Control) is sticky, it may not start without hitting the go-pedal. It's a very common problem.

 

did not know that, i will check that out next time it does it

 

Report back if it helps or not, and we'll work on it with you. But that's the first thing to try.

 

After doing some research do you think it could still be iac even if it never idles rough or tries to stall once it starts

 

Yep it still could be the IAC. You can also try tapping on the IAC when it doesn't start and see what happens. My IAC in my 2000 Explorer has acted up over the last 6 years or so. A quick tap when it acts up and it starts no problem. It's surprising how much more expensive it is for the Explorers IAC than the SD.

 

If I were you I would be concerned about a mechanic who told you it needed an engine rebuild when it obviously did not. Did he even run any diagnostics?

 

We ran diagnostics tried the crank shaft bolt with and without the plugs in thinking it was hydrolocked and it would never turn over. It was a freak thing as far as i can tell. I would never have thought the engine wouldn't be able to turn a locked up ac compressor. It is what it is though he ended up saving me a couple grand when he found it was the ac compressor. Most mechanics would have pulled the engine had it rebuilt threw it back in and then figured out it wasn't the engine.

 

Your problem is heat saturation.You have a relay or something heating up and failing keeping it from crakling.Your problem is under the hood where the heat is building when parked after the drive. I would get a test light(walmart like 5bucks) and when the no start(crank) occurs get under and check the large and small terminals on the solenoid(while someone is trying to crank it) for juice. During cranking both should have power to them,the big one all the time. If not on either you have a starter circiut problem i.e. fuse going bad relay in fuse box etc. The other thing is do you have radio and other accessories when this problem occurs? If not then you are losing power to the fuse block.This means a relay or fusible link is heating up and failing. Even the big maxi fuses can fail and look fine with heat saturation. Best of luck.

 

well i replaced the iac valve this morning, so now it's wait and see if that corrects it. fuelman... as far as the solenoid, i replaced that when i replaced the starter, if that is on the passenger side quarter panel, at least that’s what i asked for and got. i'll have to check the fuses, when i replaced the starter and solenoid i checked all the fuses and everything looked ok but apparently that doesn't mean anything. i usually have the radio playing when this happens, and just recently started cutting off the ac in case that was drawing too much power but it will still occasionally not start or crank for a couple of seconds and then start. I’ve used a meter on the battery to make sure it;s not losing too much power when I crank it, and it holds its charge. I guess I’ll start pulling fuses and relays. Off the top of your head do you know what fusible link and relay to start with, where its located etc. and if i replace the fusible links and relays is that just patching the problem since its heat related (do i need to find the source of the heat and fix it)

 

Not to disagree with any of the posts here but there's a couple of other things you can consider:
Is the netural safty switch out of adjustment, try wiggeling the shift leaver or put in netural to see if it will crank.
You also could have a faulty ignition switch or chafted wires in the steering column which is common.

 

My understanding regarding a fusible link, is that once it separates, its permanently shot. I wouldn't think it could be responsible for an intermittent problem....

 

Well we're 0/2. I changed the iac and ignition switch this past weekend and when i got in the truck today after it sitting for twenty four hours it cranked for about three seconds and then nothing so i waited about ten seconds and it started right up. Drove about ten miles parked ran inside for about twenty minutes and when i came out to start the truck it cranked for about four seconds and then nothing. Waited about ten seconds then tried again and it cranked for about two seconds and then nothing. Waited about ten minutes and tried again and same thing. But this time i put it in neutral and tried and still nothing. It just cranks four a couple seconds and then nothing. Any other ideas.