Idle "Adjustment" Pin & TPS

[ParkerRocker]

So I dorked around with my idle pin a while back, and a few months ago the 92 explorer started running like ass. Tested a bunch of sensors, replaced bad O2 and IAC valve. However, the problem was not 100% fixed. I checked the voltage on my TPS and adjusted the idle pin down so that the TPS read .96V at idle.
However, even after resetting the computer, the engine still idles at ~1000 RPM. Any ideas? Checked for vacuum leaks, replaced a crap IAC gasket, still idles high...

This is of course making the assumption that the TPS is mounted within a tolerable range, would anybody be willing to post a picture of their idle pin so I can see approximately how far out is is supposed to stick? Or if anybody has any suggestions please let me know.

 

[Anime]

Sometimes the high idle is due to the ECM / ECU. The capacitors eventually leak after a number of years and when they do, it messes up the connections on the circuit board so things start going wonky for no apparent reason and obviously throwing other parts at it doesn't help. Either pulling the ECM and replacing the caps with new ones, sending it out to have it done, or buying a refurb ECM is about all you can do.

 

[pteepee69]

I would agree. I am in the process of doing an auto to manual tranny swap, and in the process I had to change out the auto computer for a manual computer. I have been chasing a rough idle problem every since I bought the Explorer. Throwing parts at it. However, the computer change made a big difference. Best it has ever sounded just sitting at an idle.

 

[ParkerRocker]

Ugh, I might have to do that. How much did you guys spend replacing the computer? This is my DD, I don't have a lot of money (college student). So a remanufactured part would be ideal...

http://www.ebay.com/itm/1992-EXPLOR...Parts_Accessories&hash=item1e62bb3473&vxp=mtr

looking at that one, but are there two different ones for manual vs auto trannys? Cuz mine is a manual, and i don't see that it specifies....

 

[jd4242]

did you set you idle 200 rpms LESS than what you want it at with the iac unplugged?thats how you adjust the idle properly.also clean your maf if you havent

 

[Anime]

If you decide to replace your ECU, you need to make sure you replace it with one that has the same part number and program code on the sticker.

You need to make sure it has the same part number (like F2PF-12A650-YA, F27F-12A650-YB, etc) AND the same program code (P2U, ANY1, etc) for it to work correctly.

The manual tranny ECUs are different from the automatic tranny ECUs, and you'll need one from a '92, not a '91 or '93 or anything else.

You could try Advance Auto Parts if they have one close to you, they sometimes have them for about the same price as other refurbs, and if you buy online with their site, you can use their online discount codes and get an ECU with a year warranty pretty cheap.

The bad thing is they want your old one back and charge a core. I think it's best to keep the original ECU and eventually have it refurbed with new caps. Obviously it's a hassle on a daily driver due to the downtime unless you're doing it on the spot in a day or so.

You could also just take a chance and try to get a non-refurb used one on ebay, or even see if anyone parting out on the site has an ECU with the same codes. I tried doing this instead of buying a refurb so I could have the stock one repaired in the meantime, but no one had an ECU I could use.


Re-adjust your idle speed, clean the MAF, double and triple check everything, but if you still wind up with a constant high idle it could be the ECU.

For whatever it's worth, mine still idles high now and then, seems to be the IAC and TPS. I figure new Motorcraft parts once I put the original ECU back in should fix it.