ECM constant(Memory) is killing battery. Help - Third Generation F-Body Message Boards

tgscooter · 11-11-2009, 07:07 PM

Problem:
Battery is dead after 2 days of no start. I narrowed the draw to my ECM constant 12v+ at the fuse box.

As a temporary fix, I've wired the Constant into Ignition Accessory.
Problem with that, the computer is relearning every time you start it.

I've been driving the car daily since April (when I completed the swap)
I've killed 4 batteries. Although, the first couple dead batteries were a combo of the PCM constant and a defective replacement Headlight actuator. The battery would be dead overnight. I've since fixed the actuator.

So basically, the draw is not severe, but its significant.

I really need help on this one. Ideas?

Setup:
'85 Trans Am
'00 TA LS1 (assuming the PCM is the same)
Battery Relocated to trunk
LS1 fuse box located in trunk
ECM located under dash on Pass. Side

tgscooter · 11-12-2009, 10:10 PM

Oh man! I am kicking myself!

Problem fixed!!!! After posting this thread last night, I decided to go over my wiring notes and references.

I reversed the IGN postive(Pink) for PCM & Battery positive (orange) for PCM.

So for 7 months, I've never had the correct PCM constant wired. There is no drain on the battery anymore.

Maybe this will help someone else who runs into something similar.

3.1EyeCandy · 11-12-2009, 11:35 PM

What's the easiest way to tell if the PCM is relearning on start? I'm afraid my PCM constant is hooked to a random pink wire under the dash - by the proffessionals that did my tune previously. Will efilive or hptuners indicate a relearn is taking place?