Idle surge since tc installed
Idle surge since tc installed Any ideas on causes for this idle surge problem i have. Ever since the Torque convetor was installed in gear at stops the idle will flare approx 1-200 rpm . It is very annoying. No ses light and no codes in pcm. otherwise car runs great. All thoughts would be appreciated. I have Diablo Predator programing in it right now,nothing custom though. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
TECH Fanatic
Joined: Nov 2001
Posts: 1,355
Likes: 1
From: Chicago (Elgin), IL
Re: Idle surge since tc installed I dunno if it affects A4 F-body's (As I have an M6), but some other GM cars have to have the TCC soleniod(s) (some do have more than one) re-calibrated if they are replaced, removed, etc.
Re: Idle surge since tc installed I believe the higher stall speed "unloads" the
motor more at idle, and any overshoot in IAC
servo position will let the RPM jump more.
The IAC will be more sluggish and slower /
more prone to overshoot and retract, as it
ages.
Lean mixture at idle also tends to make the
motor more "twitchy". You might look at the
idle trims and see if they're indicating
lean. Not much you can do about it with the
Predator, you don't have that "****". But
if you detect an overall lean bias a MAFT
might be the way to go. The GMAF may be
contributing to a lean mixture; it's been
reported to before.
motor more at idle, and any overshoot in IAC
servo position will let the RPM jump more.
The IAC will be more sluggish and slower /
more prone to overshoot and retract, as it
ages.
Lean mixture at idle also tends to make the
motor more "twitchy". You might look at the
idle trims and see if they're indicating
lean. Not much you can do about it with the
Predator, you don't have that "****". But
if you detect an overall lean bias a MAFT
might be the way to go. The GMAF may be
contributing to a lean mixture; it's been
reported to before.
