4.0L SOHC starting issues

[RangerPilot]

Explorer in my signature, '98 4.0L SOHC.


Occasionally, when the truck is somewhat warm, I'll go to start it and it will just crank and crank for several seconds before finally starting. When it does start it seems to slowly catch, then finally be normal.

I was hoping it had to do with the ancient spark plugs (see other thread), but sadly that didn't fix the problem.

Thanks for any help.

 

[d-kuzmen]

What happens if you hold the gas pedal to the floor. Could be the IAC. (idle air control valve) They are good for sticking.

 

[Ranger_man]

whenever I would kill my 4.0 SOHC, I would have to hold it halfway down for fuel kill, full throttle for any other type of kill.

Yeah, my 4.0 EARNED its keep. that engine is tougher than nails though!

 

[Brian_B]

I have not had a starting issue with mine so far (over 100,000 miles). I want to follow this thread and see what it turns out to be.

 

[scrapyardking]

I second the IAC valve being the problem.

 

[john112deere]

IAC is pretty easy to remove and clean on the 4.0, IIRC.

I'm told cleaning them tends to be a temporary fix, but mine's been going fine for well over two years now...

 

[RangerPilot]

I'll yank the IAC tomorrow and clean it (since I have to replace the thermostat anyways...it decided to stick open this afternoon).

I should add that it doesn't have any idle issues whatsoever, and as soon as it starts, it idles smoothly.

It's kind of intermittent, so I'll clean it tomorrow and drive the hell out of it tomorrow afternoon to see if it clears up or repeats itself.

Thanks for the help!

 

[d-kuzmen]

I'll yank the IAC tomorrow and clean it (since I have to replace the thermostat anyways...it decided to stick open this afternoon).

I should add that it doesn't have any idle issues whatsoever, and as soon as it starts, it idles smoothly.

It's kind of intermittent, so I'll clean it tomorrow and drive the hell out of it tomorrow afternoon to see if it clears up or repeats itself.

Thanks for the help!

Usually they won't have any idle issues, just gets stuck shut once running it'll work fine.

 

[RangerPilot]

Okay.

Over-cooling problem solved, replaced thermostat, the "bridge" part at the top was busted on one side, jamming it in a sideways-cocked, open position.

I cleaned the IAC to a nice shine and replaced it. I've only started it twice since then, both times it's cranked right up (much to my pleasure). I'll be driving it more tomorrow, and afterwords I'll be able to make a firm decision on whether it's good or not. But all signs look good!

Thanks for the help again.

 

[RangerPilot]

Well...the IAC didn't seem to help. I went to leave a friend's earlier and it cranked and cranked, just like before, before starting up. Should I be looking at another IAC related issue, or is it likely something else?

Thanks again for the help with this annoying problem.

 

[d-kuzmen]

Well...the IAC didn't seem to help. I went to leave a friend's earlier and it cranked and cranked, just like before, before starting up. Should I be looking at another IAC related issue, or is it likely something else?

Thanks again for the help with this annoying problem.

When it cranks and won't start put the gas pedal to the floor to see if it fires up. If it starts i'd be replacing the iac. If it still won't start, i'd be hooking up a fuel psi gauge and checking for low psi, excessive bleed down.

 

[RangerPilot]

Alright, will do. Thanks.