As of Nov 2022 car wouldn't start. Checked battery and was dead so got a new one. Installed and got it to start once, then next time it sounded like starter was making noises. Got it towed to a shop that determined the starter and alternator were done. (The starter and alternator were original so makes sense) Got the alternator rebuilt since I couldn't find a new one and then the starter I couldn't wait for a special order from GM so I got a reman starter. Started up after install and I picked up the car around Dec 2022.

As of March 2023 I had a no start one day which I thought was odd. Left it for a bit and came back and it started up no problem. Drove it a few times until another no start happened. Then into April I got stranded out one day because the car would not start for hours. Ended up getting it towed back to the shop to have the starter and alternator checked along with the install to make sure everything was done right. Car started for them every time until the last time they went to pull it out it wouldn't start. They confirmed the starter was good with bench tests and also the alternator was working. I picked it up and was able to drive it a few times until it had another no start.

Now as of July 2023, still having that same issue. I have cleaned as many grounds as I can with limited space. I have checked the relays which are clicking when I go to start. Fuel pump primes when I turn key on.

No codes from HPTuners.

I just bought a s257 turbo kit lol so I want to figure this out asap before I install it. Any recommendations?

 

I would ask @Kolt for the wiring diagram of the starter system and get a multimeter going. My guess is that there is something loose, possibly with either the ECM or BCM (not sure which is used for the starter)

 

I had experienced similar issues way back when I it was new/stock.
I would get the intermittent no start, no codes, it even cuts out on me for a brief second while driving on a few occasions. Luck would have it during one those episodes that I start pushing on the fuse box on one corner, and it would start up. Couldn't duplicate it at the dealership but I had told them about it. Long story short, they replaced the fuse box and no such issue since, 10 + years and counting. I hope this is the issue with you car as well? Good luck.

 

this post concerns me.

My car has been rock solid reliable, then last Wednesday when driving back home from Winnipeg (13 hour one way drive; was 3 hours from home) it wouldn't start.
Oh great.

I had it towed to a dealership, because I knew them by name (but in a post-GM bailout world, it seems as though some of the bigger dealers have bought out all the smaller dealers, so they are "X" dealer almost in name only...
I was less than enthusiastic about the level of service.
I was grateful that I got the car started (they told me they had to hot wire it) - but that was after a five hour delay, and my work order was written so that it is absolutely unusable - so I get to start from square one.


I was told that the starter was good (which makes sense since they were able to hot wire it);
I was told that it could be the ecm, a ground on the fuse box, or a ground wire...
Typically, when I pay for diagnostic work, I can take the vehicle home, and fix it - but not this time.

I have used my multi meter, and the starter relay has 12 volts, and all three grounds that come off that relay look good.
The 2 amp (BCM) fuse is good, and the 10 amp (ecm) fuse is good, so I am stumped.

I have a factory service manual set (bought when my car was still new), but these read terribly - it's as though I need decoder glasses to know the gibberish it's telling me to lookat;
As as example one chart says what you should get for readings at "B+" - it took me ages to fid the correct schematic which had a "B+" on it!?

 

Like blrt, it could be corrosion causing it. I decided to take my fuse box somewhat apart thinking about this thread and there's a ton of crud that gets in there.

 

My bad on not updating this thread.


Threw some parts at it and nothing worked. Took it to someone that use to work at GM during the cobalt days and he guessed it was the reman starter that the previous shop installed. He took it apart and found a piece inside not working all the time which was the cause of it being intermittent. Since replacing with a brand new starter it has been perfect ever since!

S257 goes in next week

 

thank you VERY much for the update!!

 

The starter bench tested fine but when he opened it up the problem was found