Mild shutter as engine sits down to idle.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Mild shutter as engine sits down to idle.
It doesn't happen all the time...probably only when the IAC holds up the revs a bit before settling down to idle.
Idles smoothly (esp for my cam).
Revs smoothly
Feel the occasional miss cruising at the lowest rpms (1400-1600ish). Jon thinks I might have a slightly sticking injector. Short-block builder thinks it's a tune issue. Hard to see how closed injectors (as it's dropping to idle) would cause the shudder.
I even thought the mounts might have a pit of play in them.
Probably two different issues?
Idles smoothly (esp for my cam).
Revs smoothly
Feel the occasional miss cruising at the lowest rpms (1400-1600ish). Jon thinks I might have a slightly sticking injector. Short-block builder thinks it's a tune issue. Hard to see how closed injectors (as it's dropping to idle) would cause the shudder.
I even thought the mounts might have a pit of play in them.
Probably two different issues?
Last edited by GREGGPENN; Apr 23, 2012 at 11:21 PM.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Bueller? Bueller?
Best guess, it's probably when the IAC is setting the idle down to the lowest level. You know...it holds the idle up as you slow to a stop...then it drops.
For a brief instant, I feel a shutter. Could that be IAC related? Seems unlikely unless it can overshoot it's mark...and end up closing off the IAC passage for a micro-sec.
Best guess, it's probably when the IAC is setting the idle down to the lowest level. You know...it holds the idle up as you slow to a stop...then it drops.
For a brief instant, I feel a shutter. Could that be IAC related? Seems unlikely unless it can overshoot it's mark...and end up closing off the IAC passage for a micro-sec.
