Idle help 91 SHO!

[Jason Gardner]

Ok new info to go on. So I did go and redo the codes only ones present are 21 and 24. The 24 code we did replace a new air charge temperature sensor so no idea why that code is still there.... But after looking over the vacuum hoses I thought I'd just see what it did if I pulled off the hose that connects near the IAC (one we did replace) motor while it was surging and as soon as I pulled it off it leveled out the idle and was running fine. I could hear the thing sucking air pretty good with it off. So is there a blockage in the hose still somewhere or is that still a problem on the IAC motor? Posting a pic of the hose that was pulled off to make it idle right.

Edit: Forgot to also mention when I plugged the hole with my finger it stalled out also. Hope I dont still have a bad IAC. Really hate to have to pull the intake again just to get to the damn thing.

 

[luigisho]

You don't have to pull the intake to remove the IAC. You can get an extension or three and get at the bottom fastener with the intake in place. Get a couple feet of extension and the correct allen/hex socket with a ratchet. Much easier. Just don't drop the bottom bolt. When I replace these now, I cut a slot out of the bottom circular casting on the IAC so it has material that can be secured by the bottom fastener. If I have to remove it --you just get a few twists on the bottom and remove the top fastener and pull it up and out.

 

[rubydist]

sounds exactly like the iac is bad, even though its new - I had it happen at least once to me.

did you reset codes after you installed the new parts? if not, that is why they are still there...

the iat sensor code is likely from a wire harness issue somewhere - could be the connector on the iat or somewhere in the harness. the main point here is that I have never seen a SHO motor run correctly with that code.

 

[SHOdded]

I think the OEM part number is FODZ-9F715-A, posted by sdpatt a while back. Still available, search the interwebz.

SHOsource and RCM should also have the part in stock.

 

[Jason Gardner]

I think the OEM part number is FODZ-9F715-A, posted by sdpatt a while back. Still available, search the interwebz.

SHOsource and RCM should also have the part in stock.

Cool so saying not to go to the local parts store to pick one up, but go with oem?

 

[SHOdded]

That's generally proven to be the best thing to do with these SHOs. Aftermarket parts (new, mass production) are comparatively iffy.

 

[Jason Gardner]

Cool, well thanks for the fast replies and all the help and info. Will get another ordered then and see if that helps. Thanks again guys.

 

[Jason Gardner]

Well tried my 2nd new IAC that had to be ordered and shipped to a parts store here and still it does not idle and surges. Soooo frustrated! The plug is getting power to the IAC we checked. Did an ohms check on the IAC, read they are supposed to be around 7.0 to 15 ohms it was in between somewhere. We did before putting the new one in checked to see if the IAC when given power would move the little rod any and it barely moved. We also took the top part of the IAC off the motor part but left it plugged in to the car (wouldn't start if unplugged) and was able to keep the car idling right by pushing in on the little rod inside the IAC. It seems like still the IAC is not moving the little rod inside enough to correct idle. Can anyone confirm that when given power to the IAC that you should see more then a little tick on the inside of the IAC?

Also a side note I am able to get the IAC off without having to pull the whole damn intake so replacing it now isn't a problem IF I am indeed going to have to try another.

 

[rubydist]

when the engine is warm, with no accessories on (no a/c, etc) the engine should just idle at around 500 rpm with the iac unplugged. If it does not, you will need to tweak the throttle stop screw in the throttlebody. It may be that the old iac would stick open so a prior owner may have adjusted the throttle plate stop too far closed to compensate. Then, when you put a properly operating iac on there, it will not idle because the throttle plate is too far closed. Its worth checking out.

 

[Eric VerValin]

A little late to the party here, but the air charge temp sender or whatever we are calling it here.... doesn't it put off a code when it's below 50 degrees outside? Not sure if it is the same on the 2 digit cars, but I know I always get a temp code when testing mine in the winter. I'd pull the throttle body off and see if those nostrils are clean going to the IAC. You say it moves, but it sounds like it's still not getting enough air. I'd check those nostrils for a carbon booger.