high idle and wont start when hot

[jeffh286]

hi everyone i got a 95 explorer that has a high idle and sometimes wont start when its hot i put a new fuel pump (in tank) in it last fall and had no problems after that but a few months ago it started to idle high then would not start if hot i changed the tps sensor air filter and fuel relay and still no luck the check engine light isnt on so dont know where to go from here

 

[bman1958]

Hey Jeff,

My son's 96 Explorerer has been doing the exact same thing for the past three days. Our mechanic told me this morning that it was a shorted temp sensor causing it to not start when hot. When cold, no problem. My son noticed the temp gauge has been reading low for a while but we didn't know that the temp sensor was related to the no start issue. Hope this helps.

 

[gtyates]

brman1958, please update us in a few days on whether or not this solved your issue. I am still tracking down an idle and a also a hot start issue like this thread describes. I have replaced the MAF, IAC, and IAT sensor so far. Truck does run better, but issue is nto totally resolved for me.

 

[jeffh286]

i changed my temp sensor last summer and the gauge still didnt work so that short would make sense in this case if they say it has to do with it starting but would that change the idle too thanks for the help

 

[budwich]

the temp gage sensor doesn't having any to do with engine control / starting.... there are two temp sensors.... a two wire one and single wire one... the two wire one is for engine control (iirc).

 

[bman1958]

Yep, this did the trick. It starts right up hot or cold. Have no idea how the temp sensor relates since our mechanic was gone when we picked up the Explorer. If I get a chance I'll look for the repair bill and detail what specifically was done, which sensor was changed, etc.

 

[ModT1927]

hi everyone i got a 95 explorer that has a high idle and sometimes wont start when its hot i put a new fuel pump (in tank) in it last fall and had no problems after that but a few months ago it started to idle high then would not start if hot i changed the tps sensor air filter and fuel relay and still no luck the check engine light isnt on so dont know where to go from here

I have 1993 Ford Explorer XLT 4x4 and had the same/similar issue. Here is what I found in my case (after doing a long list of troubleshooting, none of which listed this as the problem):
MY SOLUTION:
THE IAC HAD SHORTED OUT, AND IN TURN, SHORTED THE COMPUTER. THE SOLUTION WAS TO REPLACE BOTH THE IAC AND COMPUTER.
I can explain each and every step of searching for an answer (the main ones being vacuum leaks including o-rings at fuel injectors, all that I faithfully ruled out).
Replacing the IAC allowed the truck to run, but not consistently idle correctly. Stalls were frequent. My solution to that was to mechanically increase the idle speed.
I just did not believe that there was no short circuit protection for the computer. Well, there is not. At least not in my case. And, even with the factory manuals, nowhere does it say to replace the computer after a sensor short. Eventually my mind went in that direction as the symptoms were highly suggestive of idle fuel/air ratios changing (i.e.: vacuum leak). (PS: my truck does NOT have EGR.)
I ended up going through 2 different computers before all returned to normal.
(Sort of: the performance with the replacement computer is slightly less than original and while that can be corrected by someone with a computer, I don't have the money to pay for either the program or for the guy who knows how to use. I am satisfied with the current state and as I don't drag race, the ever so slightly slower truck is just fine with me.)
As you are still prior to 1997 when all systems had to be pretty much the same, you are hampered, as was I as to how much diagnostics you can do. The original cost of a proprietary diagnostic machine to Ford dealers was $60k. So much time has passed, they no longer keep those, and I have not been able to find a used one for sale.
Here's wishing you luck in your search.