2010 Corvette GS 53,000 miles Car started giving me the “Service charging system” DIC.... Volts would go from 14.4 down to 11.8 ok so changed the battery to a red top optima battery, because I have a stereo system with two amps....nope changed the alternator because hey maybe that’s what dropping the voltage.... nope changed the belt maybe it slipping.... nope...changed the belt tensioner... nope..... did the big 3..... nope..... changed the clip to the alternator because I was hearing a little noise.... nope ....changed the starter.... nope now for bolt on Mods on the car....TSP headers all the way back, dyno tuned, K AND N CAI, black widow mufflers, now the dang car will stay at 14.4 volts when driving soon as I accelerate hard it stays at 11.8..... I’m lost for what else to do or check..car is in pristine condition had it for 7 years always garaged only driven in Sunday’s. Has never seen rain water. ANY help is appreciated.

 

i assume you mean an 09. but when you say accelerating do you mean hard accel or just any? have you checked the wiring for your stereo system? could be weird wiring or maybe a short somewhere that only touches when accel. otherwise dont know. good luck

 

Good point about the stereo wiring. Maybe he could pull the fuse for the stereo and see if that makes a difference. For that matter, pull other non-critical fuses one at a time as well.

 

Using NGK copper plugs?

 

C6 charging system is overly complex, but not impenetrable. A voltmeter, wiring diagram and a diagnostic strategy are your freinds...
Check the basics first... junction point at the starter (if not bypassed directly to the fusebox), engine grounds, battery ground, etc.
Some kind of load test on the alt would be part of those basics. It's possible for them to charge proper voltage, but not produce enough amps to maintain that under load.
Not uncommon to get a defective new or rebuilt alternator right out of the box. One of the big pitfalls of the parts-swap method of diagnosis.
Regulator is built in to the alternator, and should charge ~14.2 steadily with the small plug disconnected, and only the red power lead connected.
Maybe monitor voltage directly at the alt? If it stays steady there, alt is OK. If it still drops in the car, the problem is downstream somewhere, maybe poor connection somewhere farther down the circuit.
Also the chance of some heavy current consumption drawing the voltage down, but if the alt is producing its rated amperage, that's a SH*TLOAD of current.
Shouldn't be hard to find... look for something smoking. Or glowing. Or on fire.
If it remains 14ish volts throughout the car, but drops when the small connector is plugged in, the problem might be in that overly complex charge monitoring/control circuit.
The factory wiring diagram and troubleshooting steps will leave you more lost than when you started.
Then there's also the possibility that the voltmeter isn't accurately reflecting what's going on in the rest of the car...
Time for a pro?
Good luck, let us know what you find!

 

I've had that happen before and it was the starter solenoid that had gotten brittle which allowed one of the terminals to come loose.

 

They didn't make a Grand Sport in 09.

 

Aftermarket spark plugs and wires, that do not have enough resistance/causing FRI through the spark plug coils to the ECM, and the ECM is clipping the output voltage of the alternator.

Or, it just time to pull the alternator apart to clean it, since it could just be that the high revs are kicking the brushes back into the cage/they are not rebounding fast enough for the alternator to hold its output voltage. Or could be a broken winding support on the rebuilt alternator that is causing the problems at high rpms instead (why it's better to just rebuild your own alternator).

https://www.corvetteforum.com/forums...nator-fix.html

 

I doubt he needs to clean the alternator since he has already replaced it and that didn't fix it.

 

I have changed out the alternator already

 

And I have ngk iridium spark plus recently changed those out too.

 

Could it be possible the tune is out of wack?

 

According to the factory manual troubleshooting steps, one of the failure modes is a bad ECU.
Unfortunately, the manual also contradicts itself on that point...
One reference there suggests that the ECU controls charging, while another might be taken that the ECU merely monitors charging voltage.
Perhaps there is a setting in HP Tuners to control alternator charge, I don't know...
Please refer to post (#4?) above.... Does it charge consistently at 14+ volts with the small plug connector off?

 

As previously said, the junction point (starter solenoid) is where positive battery and alternator tie together. On the starter, the solenoid post gets brittle and the connection becomes loose and degraded with heat and over tightening.

I had the same issue. Look into the Mechman alternator. As an option, they'll sell you a thick cable that ties alternator directly to the fuse box. Problem solved.

I also replaced starter because it needed it.

 

STL Mike, it seems to be a fairly easy task to have a cable made up to run from the alternator to the fuse box, but the brittle solenoid post issue still remains. I must be missing something. Please explain.

 

Just reread your original post and saw you changed the starter. When you tightened the nut on the stud that joins the battery and alternator cable together did you crank that down? That stud is held by plastic and folks crank down on it and break it, which causes intermittent connection. That's why the cable from alternator direct to fuse box is a good electrical update.

The C6 alternator is underpowered when you start adding amps, you have 2. You may consider the Mechman alternator. 170a and 14.4 solid volts (14.2 with engine hot) and I did the cable at the same time. No more electrical issues

 

Mike thanks for replying this issue was going on with the old starter and still doing it with the current starter. I was looking at that Mecham alternator before thinking I needed a high voltage alternator and you saying that confirmed it for me. I will purchase it and see if that hopefully solves this. One thing I need to mention is now I don’t get the DIC service charging system coming in anymore. But when I hit the gas it goes from 14.4 to 11.8 and stays there until I let off the gas and rpms go back down.

 

I would do the mechman with cable upgrade and wouldn't look back. There's a vendor on here that sells them, search around and I'm sure you'll find

Let us know how it goes!

 

Have seen too many rebuilt alternators that either have a broken wind basket, or wrong voltage regulator installed in them to begin with.

 

Where in CA are you located? I have a spare MechMan 170 if you want to try it. Any chance you put a voltmeter on it and try accelerating hard?