2005 Aveo alternator run-on after Passport removal

[zombieallen]

Hey, all. First time posting, here

I searched the forums but didn't find quite what I needed. I've got a 2005 Aveo that's been paid off for years. At some point in the car's life, someone installed a Passport GPS system, I guess to keep track of the previous owner. It's only ever been an inconvenience to me, making me wait until the unit beeps before I can start the car. Last week, the unit went out. I had to remove it and rewire the ignition in a laundromat parking lot.

They did a hack job when they installed that thing. I un-spliced the wires running to it and re-wired the ignition switch. I was able to start the car and announce to the world that I'm the smartest man alive, but when I turned the key off, the car kept running. I had to unhook the battery to stop it. I thought maybe I had damaged the ignition switch while working on it, so I replaced it. No dice. The car still runs on.

Any help you guys could provide is much appreciated. Thanks!

[avguy]

One way that could happen is if the red/black #1 wire was connected to either the red/black #2 wire, or the #5 orange wire. Not sure what other possibilities there might be which would create that situation.

[zombieallen]

One way that could happen is if the red/black #1 wire was connected to either the red/black #2 wire, or the #5 orange wire. Not sure what other possibilities there might be which would create that situation.

Thank you for the response, I'll have a look at that when I get home from work. But from memory, they spliced into the yellow starter wire, piggybacked the constant 12V, and left everything else intact (or so it seemed). I certainly could have missed something, though.

[zombieallen]

So, the plot thickens. Yesterday, I went and checked the wiring again. It's definitely wired correctly. I figured out that pulling the DIS INJECTOR fuse kills the engine (of course), but here's where it gets odd. Without the fuse, the car runs normally. The electronics work, it starts, it drives, it dies when the key is turned off and removed. If I replace the fuse, all the problems come back. It makes ZERO SENSE.

I also noticed a slight high-pitched noise coming from the engine when the car is off. I tracked it down to the alternator and found the noise goes away when I remove the negative terminal from the battery. I'm thinking a bad diode is causing a parasitic drain on the battery. That would explain why the battery takes a charge from the alternator but never holds it with the car off. I might have shorted the diode when I pulled the hot wire from the battery like an idiot when it initially wouldn't stop running.

Again, any thoughts are appreciated.

[avguy]

Yep, the stuff you described is REALLY weird. If all of the ignition switch wiring is ok as you indicated, then it almost sounds like someone changed the wiring in the SP201 splicer (although I can't imagine why anyone would do that). SP201 is the common link for the #7 fuse output, and a bunch of other stuff in the operational systems. And one of those is the exciter wire that goes to the alternator, so if that's still being powered after the key shutdown, that might explain the noise from the alt.

Changes to SP201 is just pure speculation on my part, and I'm not even sure exactly what rewiring would need to be done in order to produce what you're seeing. The actual cause might be something completely different. However, regardless of the specifics, IMO either someone made changes to something in the factory wiring, or there's been wiring damage and crossed wires, resulting in these weird issues with your Aveo. I hope you don't have to resort to unbundling harnesses in order to get it resolved!

[petrified.rabbit]

If you alternator is whining (or whatever the noise it that you are calling it), and it is causing a drain on the battery when the car is off. Then the alternator is sending power to the same spot when it is running. Which could in part be charge to the DIS Injector circuit when the fuse is in, which could keep it running. I believe it is a short to ground circuit, cut power from key, kills engine. But if it finds an additional power source from a short in the alternator, it can keep running. In fact, this short could be electrifying a lot of the engine components. So be careful.

I would replace the alternator, and I would imagine some of the other issues will go away.