AC on and it idles at 3000+ WTH?

[Darkness]

I've played with the throtle follower tables and dont know what to do. When I turn the AC off it goes back to normal but it sometimes likes to idle at 2000rpms. I dont know what it is and I cant replicate the problem, it just happens out of the blue some times other times it runs like a champ!!!

:help2:

[SSpdDmon]

Engine>Idle>Learning>Parameters and other tables

After getting the desired airflow dialed in, you might need to expand the learning ability of the PCM or adjust the decay rates to combat your condition.

[ringram]

Tordne suggested turning learning off altogether which I did, no problems so far. There is also a table for adding extra air when the AC is on, you might want to reduce that.

[Tordne]

Can you explain the circumstance. For example:
1) The idle hangs when coasting and will settle about a half second or so after coming to a complete halt.
2) Sitting stationary and idling fine, I blip the throttle and it takes a long time or the idle to settle again.

Cheers,

[Darkness]

Can you explain the circumstance. For example:
1) The idle hangs when coasting and will settle about a half second or so after coming to a complete halt.
2) Sitting stationary and idling fine, I blip the throttle and it takes a long time or the idle to settle again.

Cheers,
These are more of less the conditions when the AC is off, some times its reved up to 2000rpms and at complete halt stops after 2 or 3 seconds. Not always though.

But with the AC it just stays up in the rpms, if I blip the throutle comes down to 1000 for a sec but then it shoots up to 3000 again.

[Tordne]

These are more of less the conditions when the AC is off, some times its reved up to 2000rpms and at complete halt stops after 2 or 3 seconds. Not always though.

But with the AC it just stays up in the rpms, if I blip the throutle comes down to 1000 for a sec but then it shoots up to 3000 again.

Send me your file if you don't mind. email is andrew and holdencrazy dot com

[Darkness]

Send me your file if you don't mind. email is andrew and holdencrazy dot com
Sure thing thanks. :)

[Darkness]

I might be chasing something in the tune that might be hardware related. I noticed today that I have these 2 trouble codes.
P1518 "Throttle Actuator Control (TAC) Module Serial Data Circuit"
P0108 "Manifold Absolute Pressure (MAP) Sensor Circuit High"

Could this be the cause of my car wanting to idle at such high rpms? I mean its getting worse and worse, yesterday I couldnt drive it at all as it would rev it self to 4500rpms in neutral while cruising and it would keep the car at 80mph without me hitting the throtle! And at full stop it idles like a dream at 950.

Oh I logged the Absolute throttle and it shows it at 11% when its reved like that and when its not reved its only at about 7%

[Chuck L.]

A Thread on another site, about problems with the FAST 90???
"2000FRC 408ci 520rwhp Callies crank, Eagle rods, Diamond pistons, Absolute Speed heads, 244 248 cam, LG Headers, FAST 90/90, 11.6cr, EFILive" :nixweiss:

[Darkness]

Whats your point?

[Chuck L.]

Whats your point?

Could the T/B be causing the idle problem[s]??

[Darkness]

I dont know but it just started doing it, and now I have these codes, could it be the MAP sensor that went out?

[Tordne]

Do a compare of your tune vs. a 2000 stock Vette. I noticed that a number of the MIL enables etc. had been messed with (for some reason).

I think you will end up chasing your tail a lot in that tune. A bold/broad statement.. But, it is relatively easy to make power tuning on a dyno, but it is A LOT harder to nail all the idle transition stuff to give the car manners.

[Darkness]

Do a compare of your tune vs. a 2000 stock Vette. I noticed that a number of the MIL enables etc. had been messed with (for some reason).

I think you will end up chasing your tail a lot in that tune. A bold/broad statement.. But, it is relatively easy to make power tuning on a dyno, but it is A LOT harder to nail all the idle transition stuff to give the car manners.
Yeah I think I'll have to start with a brand new tune. I got my LC-1 hooked up and reading correct so I'm going to start tunning the VE with it.

[Tordne]

If you do start from a stock tune again make sure you change the B0104 value as you have a 408 ci motor ;)

[Darkness]

OK, this problem HAS to be mechanical, there is no reason for the car to rev it self like that. I mean sometimes it drives and idles like a dream, other times is just revs it self to close to 4000 while rolling, once its stopped it comes down to normal after a few seconds. Sometimes it revs it self out of the blue so hard that it makes the traction control kick in. (its been raining these days)

What can I do??? :(

[joecar]

Have you checked the return spring on the throttle shaft/cam at the TB, is it weak/broken...?

[Darkness]

Have you checked the return spring on the throttle shaft/cam at the TB, is it weak/broken...?
Its an ETC and when I log the absolute throttle when its idling fine it shows ~7% throttle and when it goes crazy it shoots up to 12% for no apparent reason.

[SSpdDmon]

You should log all airflow adders to see if you can figure out which table it's coming from (cracker, follower, etc.).

[Darkness]

You should log all airflow adders to see if you can figure out which table it's coming from (cracker, follower, etc.).
Ok will try but dont know if I'll know what to look at though.

[Tordne]

It you are still having the problem of a high idle, by logging the Throttle Follower, Throttle Follower airflow PIDs you can see if either of those could be affecting the high idle.

For example if you were to see that Throttle Follower was adding 5 grams/s of air while you were idling at 3000 rpm then you could guess that you may need to lower the Throttle Follower airflow table, and/or increase the decay.

You should (if you haven't already) do the RAFIG stuff and correct the Desired Airflow table as this will cause idle to hang also.

[Darkness]

You should (if you haven't already) do the RAFIG stuff and correct the Desired Airflow table as this will cause idle to hang also.
Sorry for the ignorance but what is RAFIG?

[Doc]

RAFIG=Running Airflow in Gear

http://forum.efilive.com/showthread.php?t=149

http://www.ls1tuning.com/iboard/index.php?showtopic=9

http://www.ls1tech.com/forums/showthread.php?t=309671

:)

[Darkness]

RAFIG=Running Airflow in Gear

http://forum.efilive.com/showthread.php?t=149

http://www.ls1tuning.com/iboard/index.php?showtopic=9

http://www.ls1tech.com/forums/showthread.php?t=309671

:)Wow lots of info thanks. I'm sure I'm chasing my own tail on this one because from the codes it threw out it could be either the map sensor or the throttle actuator control having issues. I'll look into the RAFIG and check back in later.

Thanks