High Idle and IAC reset issues

L78MARK · Post by **L78MARK** » Sat Apr 05, 2014 7:34 pm

I am having a problem with my idle after the engine warms up. I have a 1990 Olds Touring Sedan with a 1228253 ECM. The original engine was a 3800 LN3. I put a 2000 Supercharged L67 3800 in and had the ECM tuned to work with this engine. I am using TunePro RT ver-5 to make changes and do my data logs for the tuner. The car runs great other then the high idle when warm. The engine idles around 1100 when I start it cold. It goes up to 14-1500 when it warms up. The IAC should reset when I shut the engine off and restart it but it does not. I have to shut it off and disconnect the battery to reset the IAC and bring the idle back down to the normal 650. I replaced the IAC with a known good working one and no change. I even tried replacing the ECM with a known good working one. I checked all of the vacuum lines and all is good with the car except for the fact that I have to power down the ECM to bring the idle down to normal. any help or ideas would be greatly appreciated…
Thanks....
Mark

Post by **Mangus** » Mon Apr 07, 2014 10:08 am

There's generally an idle speed versus coolant temp table to control idle speed. What's shown in that table?

L78MARK · Post by **L78MARK** » Thu Apr 10, 2014 2:39 pm

.
Mark hear is a screenshot of the idle RPM vs coolant temp table you asked about.
.

Post by **robertisaar** » Thu Apr 10, 2014 5:39 pm

uhh...... i think a BIN/XDF mismatch is happening here. that is easily the oddest looking desired idle table i've ever seen.

Post by **Mangus** » Thu Apr 10, 2014 5:47 pm

Yeah, looks backwards to me, with one cell that isn't congruent with the rest..

L78MARK · Post by **L78MARK** » Sun Apr 13, 2014 6:47 pm

You are correct; I had the latest BIN, my working ADX and the wrong XDF file. As you can see that one is for a 1227165 F-body.

This one does not have a Idle RPM vs Coolant temp table. I guess this XDF is also wrong. It is the best one I could find.

Post by **Mangus** » Sun Apr 13, 2014 8:17 pm

You need either the 5B1 or 5B2 definition. I don't have them on my site, but they're out there somewhere.