I have a rough idle due to timing fluctuation at idle. I've seen threads posted saying something similar but haven't found any real aswers yet.
I have a 92 gta 730 ecm 8d mask and right now trying trax's super aujp bin.
I have my closed throttle timing set at 20 degrees, and in the main timing table I've set everything from 400 rpms to 1000 rpms at 20 degrees and still at an idle only (as seen on Datamaster and tunerpro) my timing jumps from 20 to 30 degrees (a 10 degree variation) about every 4 to 5 seconds and the motor gives a shudder when this happens..Is there something else for me to check in the bin or do you think this might be a mechanical problem.
Just to clarify it only happens at idle ..
when i increase rpms the timing and motor
are smooth as silk... by the way stock cam, heads, has headers, no air injection and a stealth ram

 

There are two SA functions that can cause the timing to jump like this: idle control SA and stall saver SA. Zero those out and see what happens. May make it easier to track down the problem.

RBob.

 

I've searched and searched and I don't have those listed in my ecu file. I have closed throttle SA which might be the same as "idle control SA" except it includes many more rpm settings other
than idle. As far as stall saver SA , I don't
anything that comes close.. I have never
edited an ecu file.. can someone help intruct me how to add these items if possible or direct me where to get an ecu file that icludes these.. thanks again for the suggestion RBob..

 

Does anyone have a clue or am I out of
luck here?

 

Try to log the stutter and post here...

 

I'm still working on figuring out the .ecu stuff.
But,

L81EB starts the idle retard timing corrections.
the first entry is for a 0 rpm timing correction, then 50, 100, 150, and then 200 RPM timing error

L81F0 starts the timing advance idle speed correstion
Again 0-50-100-150-200

Just for grins, I suggest you first 0 this entries out, and see if that helps your idle, you can just use a Hex Editor for that.