95 explorer phantom problem

[Armyguydan]

OK, i have a 1995 ford explorer, all stock with a strange problem. I can drive the car for 400 miles and it will run fine, but only if i dont shut it off. If i shut it off when it is hot, 75% of the time when i try to start it it will start but will run really ruff. When it does this it will actually, according to rpm's, say its not running. Now if i press on the gas a little and bring it up to 700rpms or so, it will run perfectly, not backfire, no hesitation no nothing. but i let my foot of the pedal and back down to 0-100rpms and stalling, hesitation, all the fun stuff. Since, if i keep rpm's at normal range with foot on pedal, it runs ok i thought it might be the TPS, so i replaced that....and nada, didnt work. I have replaced the MAF and that didnt fix anything either. When i originally bought it, previous owner said it was the fuel pump, but like i said, if i get the rpm to normal by giving it a little gas it runs flawlessly. Please help as if i dont have any other direction to go, im going to drop the tank this weekend and replace a $200 part(fuel pump) that i do not think is the problem. Thanks

 

[Armyguydan]

Anyone???

 

[Joe Dirt]

I would check your IAC. Have you checked for any codes? I had similar issues with a bad IAC, another time a bad EATC, and another with a dirty MAF sensor. I'd think IAC, since it obviously affects the idle.

 

[Armyguydan]

Can I clean an iac? Or just replace?

 

[Joe Dirt]

Some guys clean them, they don't seem to last though, I just replaced mine, they're not too expensive- you can get them on rockauto.com pretty cheap...

 

[Armyguydan]

on a side note, i dont think i said this before. when it is hot and i turn it over, it starts quick, and like it something fully hasnt caught...It is sooo hard to describe. I went out and took off the IAC just to see how it looked and it dosnt look to bad, prob something to replace just to make sure. When it does this it almost reminds me of when you are having trouble starting a car and it catches for that quick second but dosnt catch all the way and dies......also just had the starter replaced last week so i know its not that. the eatc, is that the electronic automatic temperature control? dosnt that have to do with hot cold air comming into the cab, not anything with the vehicle running? Its not throwing any codes and check engine light isnt on either...this dam thing is sooo confusing. Think i might by the IAC and rent a pressure guage for the fuel. What pressure should the fuel line be at at idle?

 

[EricM9104]

Check the relay box under the hood for moisture. Every once in a while my fuel pump relay acts up resulting in a no start or uber rough start... No start, I pull relay and put it back in and works fine...

 

[gtyates]

The coolant temp sensor can also cause this condition. Been there on mine. I did not have a CEL either and no stored codes when the system was scanned, but this sensor was my hot start issue.

 

[Armyguydan]

Hmm, thats funny as my temp guage always jumps around....can I ask how this could cause my problem?

 

[nssj2]

If that is your problem, here is what the temp switch does. It senses the temperature, obviously, to rich or lean out the AF ratio. I'm not sure if it affects timing on these trucks. Anyways, if you're too rich it'll cause a popping and maybe even miss at idle. So, theoretically, it could be sending a signal to the ECM that the engine is cold, when in reality, it is hot. There are 2 temp sensors on your vehicle. One provides the signal for the gauge, and one for the ECM. The best thing to do right now is rent an OBD2 Scanner from autozone. They can graph live data. Take one "snapshot" of the truck running fine, and one "snapshot" with it stumbling. That will find any electrical problem real quick. Hope that helps!

EDIT: Didn't see yours was a 92. Forget that last scanner part *doh*

 

[Armyguydan]

It's a 95, bought a new one

 

[Armyguydan]

Lol would the iac not having the gasket cause my problems? Lol realized this morning that it didn't have one installed last night..

 

[gtyates]

Lack of gasket on the IAC could be a cause of this for sure. Allowing too much unmetered air in.

 

[95ExpLim]

If i shut it off when it is hot, 75% of the time when i try to start it it will start but will run really ruff. When it does this it will actually, according to rpm's, say its not running. Now if i press on the gas a little and bring it up to 700rpms or so, it will run perfectly, not backfire, no hesitation no nothing. but i let my foot of the pedal and back down to 0-100rpms and stalling, hesitation, all the fun stuff. Thanks

From the symptoms it does sound like a bad temp sensor or its electrical connection.

In one post you say the temp "always jumps around". I can't remember if those are a one wire (ground return through the threaded section) or a two wire. On a one wire sensor I'd check to see if someone in the past used Teflon tape on the threads -this could cause an intermittent or totally open ground return.

Have you looked for any codes? There is a procedure where you can initiate the CEL flashing a sequence of any stored codes on the OBD1 system.

edit:

If the IAC was bad it seems it'd be hard to start on the initial cold start. You'd have to press the accelerator a bit to give it some air to make up for the IAC not working

 

[baez23]

Lol would the iac not having the gasket cause my problems? Lol realized this morning that it didn't have one installed last night..

96 sport 2wd 4L 163K

I just finished the IAC changeout as well and noticed that, despite the insistence of many posters, my OEM IAC had no gasket. It also didn't have the velvet 'pellets' that others also said existed in the black cap. I brake cleaned mine (to work on an idle issue - runs great all the time, but rpms do some sort of cycle like the AC is being turned & off at random intervals) and put it back on and it would go dead after 3 seconds without heavy gas. I wonder if there was some different type of seal on the original that, when removed by us, cannot be replicated and thus messes up the mixture.

I bought an AutoZone IAC which came with a gasket and idle issues greatly decreased, purr increased.

Do you get a moose call from your compartment at all?

p.s. I'll use the suggestions on this thread to totally rid the engine of the idle jump issues and report.

 

[Armyguydan]

well, the gasket was not the problem, and of course, my explorer is not the $50 iac, its the $130 iac that they have to order. Autozone gave me the wrong ait sensor as well, and i cannot for the life of me find a fuel guage pressure tester around here. SO i have to do some calling around to see if anyone has one that i can borrow/steal lol. SO back to square one..

 

[95ExpLim]

My '95 has what looks like a "double-D" o-ring type gasket in a groove in the plastic air intake plenum. A missing gasket wouldn't cause a problem of this magnitude. Just be a small vacuum leak.

 

[Armyguydan]

Well, the fuel pressure tester snapped off the housing of the nipple for the fuel attatchment. Thankfully its not leaking...but at idle, yes of course idling normal, fuel pressure was 30lbs..really wish it would have been running Luke crap so I could have made sure fuel pressure was good. Does anyone know where/how to replace the tester fitting in the truck