Smallblock87

I can't get my 2007 CTS-V (~150k mi) to start. It's been starting rough the last few months. I replaced the alternator as running voltage was a little low. No improvement in hard starts. Replaced the battery since I do have a small parasitic drain I haven't pin pointed yet. Still no improvement.

More recently it failed to start entirely. One click and then nothing. I noticed the starter solenoid connector was toast so I decided to replace it and the starter (all AC Delco OEM parts) while I was at it. Battery has been disconnected or on trickle charger while I did the work to swap out the starter. Got everything buttoned up. Insert the key into the ignition and turned to the on position. All lights and accessories come on as usual. Turn the ignition to start/crank, I got a click one time and everything goes dead. All accessories and lights are then off even with the key back in the on position. Turning the key to start does nothing. Everything is dead. If I pull the negative battery terminal and reconnect it, the accessories and lights come back on with the key in the on position. I can repeat this continuously. Turn key to start, 1 to 3 clicks, everything dead until I reset it by pulling the battery negative cable again.

I tested the voltage under load and the battery reads 12.3V with ignition off. With the ignition on, it drops to 11.85V. Turn to crank and voltage doesn't even drop before everything goes dead and it jumps back up to 12.3.

I also tried starting using a jumper box with the same results. I went back and took a look at the starter solenoid and starter connections. I checked the G102, G104, and G105 for a loose ground. All are secure and seem to be in good condition. I bench tested the starter relay and ignition relay and both worked fine. The fact that it gets reset by disconnecting the battery has me perplexed. What would you troubleshoot next? Thanks in advance for any input.


Edit: I disconnected the alternator, starter, underhood fuse box, and battery positive terminal. Doing continuity testing I was able to identify that the alternator post reads 55.2 kohms to ground. Looks like I may have found my problem. The rebuilt alternator appears to be shorted.

AAIIIC

iTrader: (19)

Did the alternator end up being the issue?

Smallblock87

I'll update when I get it back from the shop and installed.

Smallblock87

Nope!

Still don't know what the issue is. Sent the alternator back to the shop and they said it was fine. Apparently a continuity check from the alternator positive lug to the casing will show a high resistance. I was thinking it was a sign of an internal short but I'm being told that's normal.

I'm going to clean all of the grounds, put everything back together and start over troubleshooting. My last guess is that it's an ECM issue since the ECM controls the ground for the starter solenoid. Not sure how I'll rule that out yet.

54inches

iTrader: (4)

What starter did you use? CTSV or a truck starter?

Smallblock87

Figured it out! It was a bad ground after all. Pulled all the grounds as a last ditch effort for cleaning. All were tight. However, the engine block ground had a thin film of oil on the back side. Cleaned, re-torqued, and she fired right up.

v1 Batman

can you please upload a picture of all the grounds you found? I have a 06 ctsv and mine won’t crank or start by key. I have to jump the starter reply to start it but even then she doesn’t want to stay started. And to put the icing on the cake none of my gages are reading.