V1 Anti-Theft

[KingChuck24]

Went over the car again and these are the wires that are not connected:

this is labeled acessorie power. There are a couple of things like this on the harness but those are all of the lights and mirrors.

this is part of the engine harness coming out of the bottom of the engine near the starter area.

this comes out of the wires that go to the very front of the car near the heat exchanger and radiator, could not find any connection that would fit this at the front. This definitely isn't the pedal box wire that is attached and the pedal works with the butterfly in the intake.

 

[Keckster]

The wrapped up purple wire is key on power for any accessories you might add later. The two under the engine are for the ac condenser and pressure sensor I believe. The final one up front looks a lot like the pedal connector but you said your throttle is working. what are the color of the wires coming out of that last one? battery current sensor possibly?

 

[KingChuck24]

I am not very good with my colors so here they are: I think one is a orange wire another is a orange and white wire and the last might be yellow

 

[Keckster]

yup that matches for the battery current sensor. Should be a plastic collar type sensor that goes around the negative battery cable. I doubt that is the reason for it not starting though unfortunately

 

[KingChuck24]

Not sure if I have that but I will look around.

 

[Keckster]

you could start removing fuses one at a time, crank it and if the problem keeps happening move to another. if it doesn't do anything that fuse is needed for starting. I'd keep removing fuses and leave them out until I find the problem one and check that circuit

 

[KingChuck24]

Found the battery current sensor and got that installed, unfortunately didn't change anything. Tried to pull fuses to see if that changed anything but whenever I pull a fuse or a relay the car just seems to cut itself out, dash goes dark besides maybe the anti lock system being there.

 

[Keckster]

hmm, do you have access to a wiring diagram? I would check that none of your ign 1 circuits are continuous to ground

 

[KingChuck24]

New to wiring so not sure what wiring diagram that would be or where to get it. I think I know how to check if they are continuous to ground if I got a diagram though. But then again I might need some help. Also, you guys are being very kind to help me through all this and have been very responsive so thank you!

 

[Keckster]

there is a login to a website called alldatadiy somewhere on the forums here. but here are the connects for ign 1 voltages I found:



BCM:

ECM

 

[KingChuck24]

Ok cool, those should help. So for testing direct short to grounds would I just touch one lead to the pin and one lead to the ground? Or would I test it on the ohms tab and see if there is the right amount of resistance? I will probably dive into all this stuff tomorrow and over the weekend.

 

[Keckster]

I usually just use the sound continuity test from the pin to any bare part of the chassis. test them for continuity with the key off and then you could test for 12+ volts with the key in the run position if all seems well continuity wise

 

[KingChuck24]

Ok so just started testing tonight and the first one I tested was the d6 pin on the bcm which is crank voltage and there is no continuity to ground. I am putting on of the leads on the metal of the pin and the other on the battery ground. It is also disconnected from the bcm. Am I doing something wrong is this pin ungrounded?

 

[Ross]

Run/Crank voltage only has 12V+ when the key is on.
BCM C3 has run/crank on D6, that I'm guessing that is what you are talking about.
So if you have the key on, and are testing continuity to ground on BCM C3, D6, well there wouldn't be much continuity.
If you set your meter to measure voltage, then you should be getting around 12V+ on D6, when the other lead is on ground.

 

[KingChuck24]

Got it, what is the best way to get a lead to connect to one of the bcm ports when it’s plugged in. I won’t be able to poke it from the bottom side when it’s plugged in and the battery is connected. Unless I don’t need to have it plugged in.

 

[Ross]

I did a quick read of this thread, here is the recap:
- Donor LT car with an added supercharger, ran before the goblin build.
- DF did the wiring harness modifications for the goblin.
- Theft light is on the dash.
- You did key relearn... but the theft light is still on.
- Tried to crank it but there was nothing from the starter, instead there was a ton of noise from the fusebox which sounded like a machine gun.

Did I get it right?

What I would do if it was mine:
- These Cobalts can have electrical issues as they age. Loose connectors, bad grounds.
Take every ground wire off, and sand the flat ring connector nice and shiny copper.
Clean the ground post (welded bolt to the frame) down to bare metal on the frame.
Tighten the ground post, test the start.
If that fails, I would take the top off the rear fusebox, and remove the block connectors. Inspect them, and the pins that plug into them. Re-seat them on the bottom of the fusebox, re-torque those 7mm bolts.
test again.
Do the same to the BCM block connectors.

- read up on threads here that talk about "first start". See if it gives you ideas on things to check and test.
- Did you test the starter? If you connect the top wire (12V+ from the battery) to the little post with the purple wire (this wire gets 12V+ when the key is turned to start), then the engine should start cranking. If the key was left in the run position, it should start the engine.

 

[KingChuck24]

I did a quick read of this thread, here is the recap:
- Donor LT car with an added supercharger, ran before the goblin build.
- DF did the wiring harness modifications for the goblin.
- Theft light is on the dash.
- You did key relearn... but the theft light is still on.
- Tried to crank it but there was nothing from the starter, instead there was a ton of noise from the fusebox which sounded like a machine gun.

Did I get it right?

What I would do if it was mine:
- These Cobalts can have electrical issues as they age. Loose connectors, bad grounds.
Take every ground wire off, and sand the flat ring connector nice and shiny copper.
Clean the ground post (welded bolt to the frame) down to bare metal on the frame.
Tighten the ground post, test the start.
If that fails, I would take the top off the rear fusebox, and remove the block connectors. Inspect them, and the pins that plug into them. Re-seat them on the bottom of the fusebox, re-torque those 7mm bolts.
test again.
Do the same to the BCM block connectors.

- read up on threads here that talk about "first start". See if it gives you ideas on things to check and test.
- Did you test the starter? If you connect the top wire (12V+ from the battery) to the little post with the purple wire (this wire gets 12V+ when the key is turned to start), then the engine should start cranking. If the key was left in the run position, it should start the engine.
View attachment 36951

Yep your pretty much spot on with that summary, aside from maybe adding that I shorted out the car at the start. I tried the starter and it seemed to work, I took a video if you want to check it out because it didn't sound how I really thought it might sound but the belt started moving so it is probably working. I took off and inspected the fuse box and bcm connectors, nothing to my untrained eye seemed off. Most of the conectors wiggled but since all of them were doing that I thought it was probably normal. I didn't do the grounding studs stuff yet, I will probably do them later tonight but the thing is I have already done that to the things that you said so I'm not hopeful. I have been doing a bunch of reading and will definitely keep reading but nobody seems to have a similar issue to me, or at least not that I have found so far. If I were to test the starter with all of the power connected and the key turned to the on position would it run under normal conditions? I wouldn't have thought that just turning the starter would allow all of the other systems to start going.

Video

 

[Ross]

The theft light seems to stop the starter motor from getting power on the purple wire. So if the key is on, and you bump start the car, or hot wire the starter, it will remain running. At least my LSJ did. I ran an extra purple wire from the starter, into the cab of my car. I could touch it to the Aux power/Cig lighter that I have, and it would hot wire the starter. Ran this way for about 3 months, until I fixed the GM high speed LAN data issue that I had. Turned out to be the power steering unit in my car.

All 3 studs on the back of the starter are 12V+ posts... so accidentally touching the big 12V+ battery wire to any of them is not a big deal... It would spark, and try to run the starter motor, but that isn't a short. If you touched that big 12V+ battery wire to the engine block or car frame, then it is a short for the battery, but the rest of the wiring harness wouldn't be shorted.

Cleaning the ground wires might fix it. You seem to have already done all the other things I have suggested.

 

[KingChuck24]

The theft light seems to stop the starter motor from getting power on the purple wire. So if the key is on, and you bump start the car, or hot wire the starter, it will remain running. At least my LSJ did.

All 3 studs on the back of the starter are 12V+ posts... so accidentally touching the big 12V+ battery wire to any of them is not a big deal... It would spark, and try to run the starter motor, but that isn't a short. If you touched that big 12V+ battery wire to the engine block or car frame, then it is a short for the battery, but the rest of the wiring harness wouldn't be shorted.

Cleaning the ground wires might fix it. You seem to have already done all the other things I have suggested.

Ya I will definitely try cleaning those grounds again. Do you think shorting the battery is a big issue, would it have destroyed the battery and should I try a different one?

 

[Ross]

A battery can take a quick short and be fine. Every time you use a starter motor, you basically short the battery, and surge hundreds of amperes for a moment. Once the starter starts spinning, the amperage drops quickly.

You could always run jumper wires to your goblin, from a working vehicle, and that would tell you if your battery is working.

PS: I updated my last post after you read it.