Adaptive idle wont move

[Phil99vette]

I've got a 98 corvette that is being a PITA. Its got a fairly large cam and for some reason the adaptive idle trims STIT/LTIT wont move, they are glued to 0. Its a stock tune from the factory with no mods in those tables with the exception of dropping the min coolant down. What would cause the adaptive idle to not respond and try to correct idle issues?

[PitchblackC3]

post log and tune

Are O2s responding?

[edcmat-l1]

Phil, are you scanning too many PIDs? Have you tried zeroing the long terms and see if the STs will move? Can you verify they're not working, or it's just a scanner issue? Example; won't hit target idle? Is it going into idle mode? Are the spark under and over tables working? Do you know how to verify that?

PS tune and data log dammit! LOL

[Phil99vette]

Its a 98, I'm scanning the basics. The idle is all jacked up, it feels like the STIT and LTIT are not working. It does not correct just bounces. The STIT and LTIT are all set at 0.000, the spark under and over table seem to be working. I logged another car right after it with the same setup and it worked fine. I had 2 cars on the dyno today, the 98 vette tune went fine but it just wont idle. The 2004 GTO idles perfect and dyno was a dream.

[edcmat-l1]

Its a 98, I'm scanning the basics. The idle is all jacked up, it feels like the STIT and LTIT are not working. It does not correct just bounces. The STIT and LTIT are all set at 0.000, the spark under and over table seem to be working. I logged another car right after it with the same setup and it worked fine. I had 2 cars on the dyno today, the 98 vette tune went fine but it just wont idle. The 2004 GTO idles perfect and dyno was a dream.

They're 2 completely different PCMs. The 98 won't allow you to monitor near the amount of PIDs as the 04 GTO.

Does it bounce just sitting there? As in no wheel speed at all?

I would get rid of all your pids except the idle pids and see what it says.

Still no data log?

[Phil99vette]

I'll get a data log this week. The 98s are the worst for pids and sampling rate. It doesn't bounce or anything. What would cause it to NOT go into idle mode. Could something like missfire or air pump or another sensor cause it?

[edcmat-l1]

I'll get a data log this week. The 98s are the worst for pids and sampling rate. It doesn't bounce or anything. What would cause it to NOT go into idle mode. Could something like missfire or air pump or another sensor cause it?

I would think the only thing that would cause it is if it thought it was moving. Wheel speed. But if that were the case, then the idle spark tables shouldn't work either.

[printmanjackson]

I would think the only thing that would cause it is if it thought it was moving. Wheel speed. But if that were the case, then the idle spark tables shouldn't work either.

they do that with clutch in too!

[Phil99vette]

they do that with clutch in too!

[edcmat-l1]

they do that with clutch in too!

Not really. It will still go into idle mode sitting still with the clutch pushed in. If you jab the throttle TF will kick in and then decay out, but it will still go into idle mode with the clutch in. Now with the clutch in and moving (wheel speed) it will not.