I could've sworn the last time I timed this car the timing advanced when I revved it up while the EST was disconnected.

With the EST connected it's around 20* and advances when I rev it.

With the EST disconnected it's at 10* (well maybe 9*), but it actually retards just a little when I rev it.

Like I said, I remember it advancing. Is something wrong, or is my memory going?

 

It should advance when you rev it with the EST/BYPASS open. This is a function of the ignition module.

Was the module replaced sometime with an aftermarket?

RBob.

 

Interesting.

I don't know what brand the icm is, just whatever cheapo I got from the parts store. I used an accel icm for awhile, it died, replaced with another from a parts store, eventually it started cutting out because of something I did, and now I have my current icm, which isn't really very old.

I'll pick up another I guess and try it. Any brand I should look for? I'm sure the dealer will want $50-70 for an AC delco. *edit $65 on summit. Probably more at dealership.

This car does seem kind of weak in the higher rpms. I wonder if the computer is giving me some advance at the lower rpms, but I'm not getting enough at higher rpms.

 

If at all possible get a GM module. I'll even use (and do use) JY pulls instead of aftermarket modules. If you go to a U-pull-it yard and grab some other part that you need, along with an ignition module, they usually don't charge much for the module.

As for the computor advance. There is a difference between modules. It is best to match up the 3-digit code on the OEM module with whatever GM one you get. This has to do with module latency and the correction for it in the ECM.

RBob.

 

were is the computer advance located at. took my car to a mechanic and told me there was something wrong with my advance but i have no idea what or were it is located at Please help. also is the ICM this one> http://www.autozone.com/autozone/cat...estions=%5B%5D

 

The computer advance is in the computer (ECM). The ECM does a series of lookups to get the desired spark advance and then signals the distributor when to start dwell and when to fire the plug.

RBob.

 

I was told that the advance is not working properly so inorder to fix that then i would have to get a new ECM????(wheres the ECM???)

 

ECM is under the dash on the passenger side.

Before replacing anything I would definately check the timing with a light. Just to make sure that it truely isn't working correctly. Also note that wiring issues or a bad module can also cause a no-advance condition.

RBob.