Where's the IAT on a '91 Ex 4.0L?

Folks,

I've been lurking on the message board for quite some time and this is my 1st post so please be gentle.

I have a '91 Explorer with (what my manuals describe as) the 4.0L "pushrod" V6. I'm experiencing some problems with the engine running rough, surging, and stalling (when cold) until it reaches normal operating temperature. And yes, the IAC was recently replaced. I have reason to believe that the IAT sensor might be bad. However, my manual shows the location of the sensor only on the later model 4.0L engines. And I can't seem to find it. It doesn't seem to be in the usual spot between the MAF and throttle body.

Any help would be appreciated.

What's a "IAT" sensor?

"Intake Air Temperature" sensor.

I thought it was near the air cleaner with the MAF

and the Haynes manual shows it there.

Yeah...I've got the Haynes manual too. Assuming that we have the same version of the manual, unfortunately my engine is not shown on page 6-3 where they show the location of emissions components in the engine compartment. Same thing for the picture on page 6-16; this is not what the air duct looks like on my 4.0.

On our '92 the IAT is right near the IAC...

Basically take off the snow shield (if you have one).. stand by the drivers front tire.. and look just to the right of the IAC... its right in the upper intake plenum.. just to the right (behind if you standing at the front) of the IAC

~Mark

Some of the books call it an ACT: Air Charge Temperature sensor. Thats the one next to the IAC servo. My Haynes book talks about a separate IAT sensor near the MAF but a mechanic at the dealer told me the temp sensor function is part of the MAF.


Bob

I have only seen an intake temp sensor on the plenum on the first Gen X's.. I have seen one near the MAS on a newer ranger (I believe it was still early to mid 90's)..

On our '92, and the neighbors '91 and the parts truck (a 91) it is on the intake plenum...

~Mark

Well if you looked closely at the picture on 6-3 you would see that it says 4.0L SOHC. Which you do not have.

Got it.

Thx Maniak, it was on the plenum.

AlaskanJack...understood. However, that was the reason for my post in the 1st place...the manual doesn't show the location for my engine.

Regardless, I've replaced the sensor and my Ex seems to be happy again; especially with the cold weather startups. I'll post a followup thread regarding my experiences with poor driveability, check engine lights, and the various things that I had to do to fix the problem.

The bottom line from this (and its a pretty obvious one): Don't run an engine for extended periods of time without an air filter (as the previous owner of my vehicle did). I paid the price for it but the effects could have been alot worse.

Thx for the help folks...

Originally posted by donzo
The bottom line from this (and its a pretty obvious one): Don't run an engine for extended periods of time without an air filter (as the previous owner of my vehicle did).

Click to expand...

Wow!

90-94 Ranger/Explorer 4.0's in the upper intake.

95-00 Ranger/ Explorer's in the intake tube after the MAF.

01-up 4.0's with the 6 wire MAF its incorporated into the MAF.

Look for the Grey and Grey/Red wires, its the same two color wires for all of them.

later Doug904.

In case anyone still can't find it on the 91-94