Project Undertow #388

[Dominicnicklyn]

This sounds like some of the issues I was having. The solution to my goblin's issues was
1. poor connection on the connectors under the fusebox, (reseating the connectors fixed this)
2. bad data connector at the power steering (bought a connector from an auto recycle yard, soldered it on)
3. replaced the power steering unit with used one.
I also cleaned every ground wire and retorqued all 3 of my grounding points, which have a bunch of ground wires on each one.

When your data is flowing enough to move the throttle butterfly, I wonder if jumping the starter motor would allow it to run. On my LSJ, I ran the purple starter wire into the cabin, so I could connect it to accessory 12V power, and jump the starter quickly, while in traffic. I had to do this for about 6 months, as it took that long for me to debug my data issues.

Yes, I was thinking about this while laying in bed last night.

I'm starting to belive that I solved the original issue and now I have a bad ECM ground. I only lose coms with the ECM atm.

I'll check the fuse block plugs, but I've already set them in 3 different times believing they weren't making good contact. (Had to jb weld some plastics due to over tightening them)

I've done all of your solutions above. Even swaped ecm/bcm/ignition from another same model lsj.

I'll dive deeper when I get home from work.

 

[Gtstorey]

I had to unplug the individual wires from the fuse box to plugs and tighten the individual connections to get mine to stop having intermittent issues. And the more you have messed with the plugs, the more likely you are to have this problem.

 

[Gtstorey]

But I would still start by confirming your missing “black” ECM wire is a ground and reconnecting if it is. I don’t expect any of the ECM to be unnecessary.

 

[Dominicnicklyn]

Anyone know where the power wire(s) are on the p12 ecm?

I want to test and see if I'm getting the voltage I need for the ecm to work properly. It's acting like on key "on" that it has power and is working how it should. Then if I let it sit for a short bit (30 sec to a couple min) that it doesn't have power.

 

[Gtstorey]

I’m pretty sure there have been recent links by Ross that covers wiring diagrams for all donors.

 

[Dominicnicklyn]

I’m pretty sure there have been recent links by Ross that covers wiring diagrams for all donors.

I have the pinouts for the ecm conectors, I just can't seem to find anything labeled in the "power" category.

 

[Ross]

Red wires on a Cobalt are typically "battery positive voltage" wires,
then once they go thru a fuse, are Red wires with a White stripe.
If they also go thru the run/start relay, then they are typically Pink wires, that are switched by the key.

 

[Dominicnicklyn]

Red wires on a Cobalt are typically "battery positive voltage" wires,
then once they go thru a fuse, are Red wires with a White stripe.
If they also go thru the run/start relay, then they are typically Pink wires, that are switched by the key.

Your the man, I strive to be knowledgeable like you good sir

 

[Gtstorey]

My service manual for the later models calls the ECM power “ignition voltage” and “battery positive voltage”.