Ignition timing erratic at idle

[ikema]

I just got my 87 turbo buick running again after sitting for two years in my driveway. Using direct scan i'm seeing my timing at idle jumping around between 17 deg. to about 21 deg. I am running an extender chip with 16 deg. timing at idle ( 91 pump gas ). The timing chain was replaced shortly before I stopped driving it and it was running great when i parked it. I have a factory service manual and thought it might be related to the esc module but the manual is pretty vauge on this subject. I'm thankful for any help I can get.

 

[ikema]

sounds like this is not a common problem

 

[earlbrown]

Just to verify what DS is showing you, I'd put a timing light on the balancer and make sure it's actually jumping around.

 

[TurboBob]

DS is showing what the timing wants to be, not actual.

idle timing should be 21-25, I wonder if the ECM mode is changing or something.

a timing light should be the next step.

or, it could be bad/noisy data. any other data jumping around?

B

 

[ikema]

I put a timing light on it and it appears to be bouncing around like the DS was showing. Tried another ecm and got sime results.
Thanks for the help

 

[TurboBob]

post up the chip number and the DS log.

B