I have a 2011 GS manual coupe that's having trouble starting and keeping a charge. Here's the situation:

- Saturday morning - Went to cars and coffee and started up fine. Came back home and everything was fine. Went to leave a couple hours later and seemed like a low battery trying to turn the engine over but still started up. Thought it was weird and went on driving. Stopped for lunch and when trying to leave, really struggled to start up. Once it was running the voltage stayed around 11.5V. Took it to a buddy's place to check it out. Pulled in still at 11.5V, turned it off, then back on again and was around 13.5V stumping us. To see if it was either the battery or alternator, we started it up and pulled the battery leads off. Well it stayed running at around 13.5V. We couldn't recreate the voltage drop and was able to start right up every time. As preventative maintenance we replaced the alternator to try and mitigate it being a bad alternator.

Then I left with the vette to go on a trip I should've already left for at lunch. Drove about 3 hours monitoring the voltage and never dropped below 12.8-ish. Even stopped at a rest stop, turned it off and started right up afterwards. The whole way I had on the AC, listening to music, driving as I would usually, while still monitoring the voltage. Everything was fine for the rest of the day.

- Sunday - Everything was fine.

- Monday - Everything normal again.

- Tuesday night - I get in to go to a store maybe 10 minutes away and starts up fine. I get there, do my thing and get back in about 5 minutes later. Hit the starter button and it just clicks. As in the starter made a singular click and nothing else happened. Waited about 30 seconds, hit it again and started right up. Brought it back where I was staying, voltages were around 11.5V. Tried to start it later that night and did the same thing, click from the starter. That's all it did. Tried it about 5-6 times and just clicked so I left it and went with the rest of the family in a different vehicle.

- Wednesday morning - Went out to start it again to take it to a nearby dealership to fix and had no problem starting up. HOWEVER, it started at 11.5V and steadily dropped on the way as if the alternator wasn't even working. Right as I got into the dealer parking lot the whole thing died and shut off at around 9-ish volts. Had to use a jump box the get it the rest of the way into the service area.

Now it has taken the dealer 2 and a half days to say that it's the alternator not working, even after I told them that I replaced the alternator this past Saturday with the same symptoms as the original one. I even mentioned other people having solenoid problems and they still said it was the alternator. This afternoon they called me back and said they found that a starter solenoid terminal was about ready to break off and was loose. So now they're going to replace the whole starter assembly and not the alternator.

My question is, have any other of you guys had starter and voltage/charging problems at the same time with the solenoid? I know that having a bad ground in one place can screw up other stuff but I really don't know anything else that could cause the charging to stop. Any insight would be helpful.

 

First off you NEVER remove the battery terminals while the car is running…that was something they did back in the 60’s to see if the car kept running or not seeing if the generator was bad…the battery acts as a “buffer” or “surge protector” for the electrical system…if the alternator was overcharging you could have fried EVERY module in the car if the voltage suddenly spiked…the B+ cable from the alternator goes down to the starter solenoid…the battery positive cable connects there too…if you have a bad connection or corrosion the battery will not charge…this is the first post I have seen in years where a dealership actually diagnosed a car correctly.

 

For whatever reason, the alternator output is connected directly to the terminal on the starter solenoid, and then the +ve post on the battery is connected by another cable to that same post on the solenoid. It’s not uncommon for the Bakelite that holds terminal to fail which in turn causes the connection to become loose and fail. The terminal stud and the nut can also corrode and cause continuity problems. Replacing the starter would certainly fix the stud problem as long as the terminal ends of the cables were still in good shape and cleaned up. But it’s probably overkill to replace the starter since the solenoid is relatively cheap and can be replaced. GM mechanics tend to be parts replacers and not repairers so it’s not surprising that they would replace the starter because it comes with a new solenoid.

 

I second this. Pretty much had the same symptoms as the OP. My problem was a loose, corroded connection at the starter. I would encourage the OP to get under there and check it out, if possible.

They key point is that the alternator connects to the battery AT the starter solenoid. If that’s loose, you could have starting or charging issues, or both.

 

I would make a thorough visual inspection of all alternator and battery wiring.
If no wiring issues were found, I would remove the alternator and have it tested.

I suspect you have a failed alternator.

How old is the battery?
Reminder. Over-discharging a lead acid battery shortens the life of the battery. (Deep cycle, the exception)
I would pull the battery, give it a full, slow charge (compatible battery charger) and have it tested also.

Know how to have a screamin' good time?
Try diagnosing a weak battery in tandem with a failing alternator.

fat biker