Rupert pupkin

I know what it is. Checked battery, and its GOOD. I know the alternator could be the culprit, but could it be a starter as well? Z didn't want to turn over, but eventually did after 3-4 tries.

TRSCobra

How did you check the battery? Load test or just with a voltmeter? Could be the connections at your battery or starter, also.

Rupert pupkin

Load tester... It was reading somewhere mid 11-12. I guess its suppose to be around 13 volts when charging.

TRSCobra

12.6 is fully a fully charged battery, and it should be over 14 when the alternator is charging it.

Rupert pupkin

When the car was on it was charging at around 11 and popped a code after. P0335-Crankshaft Position Sensor and p0340-from the looks of it is just some on going detection code. Going to test the alternator first @ auto zone's bench tester. Hate electrical sh**.

TRSCobra

At least these cars are about the easiest cars to change the alternator on.

Rupert pupkin

I know. I just turned the car on and fired right up, no engine light either. Checked all wires, and everything seems legit. Hopefully this doesn't pop up again, and hopefully its not the starter either. Looks like thats a B**CH to swap out.

Mark2009

Electrical interference from non-stock spark plugs (especially the copper variety), and I would presume non-stock plug wires and non-stock coils has been shown to produce this warning due to corruption of the low level signal communication between the alternator and the ECM/BCM/whateverCM.

Depending on what you have and how long you've had it in that department you might consider those components as well.

But if the voltmeter is showing less than 14 while the car is running, at least after a couple minutes, you most likely have a battery or alternator or connection (the dreaded starter) issue.

Treadhead

Send a PM to 98MOGT. He recently had the same issue. Turned out the plugs he was using were the culprit; too hot a plug I believe.

Undy

Exactly, my TR6s created similar problems until I went back to OEM plugs. At 10K miles after the heads/cam/intake/plugs/etc change I pulled the plugs for the wiggle test and the coloration of the oem plugs looked perfecto.

stefuel

You don't have to rely on the cars volt meter when trying to evaluate the output of the alternator. If you have a digital multimeter, you set it to DC volts, ground the black lead to the block and touch the red lead to the output lug on the alternator. That will tell you the output at the source.
Then go back to the battery and test there. The voltage should be the same or damn close. If it's not you need to check all connections including battery, starter and ground straps.

Rupert pupkin

Its definitely reading 10-11v for 20 minutes when I was driving late last night. Didn't even jump to 14v. Ive only had the build on the car for about 5k miles. The battery is holding a charge which is good. Just have to dismount the alternator to see if its that. Im REALLY hoping its not the starter, bc the Z wouldn't turn over after 3-4 starts.

Deff will

Will do that today.

rustybridges05

Im on my 4th alternator....After all that i went with a HD one and spent the extra $$$

stefuel

I just had one of those "funny" thoughts. I wonder what the alternator drive ratio is on a LS7? For the sake of conversation, lets say it's 4:1 over driven AND you're one of those who like to tickle the redline on a regular basis. You're asking that poor alternator to suffer 28,000 rpms. It's a wonder they don't just fly apart

Rupert pupkin

Will having a low charging fault cause your abs/TC go haywire?

gaklid

Mine did...I was out of town in my Z....It was running/starting perfectly. I went into the movies, and came out to a dead stick. Jumped it, & while running saw 14 volts, but as I kept driving the voltage got lower & lower. I was headed to Autozone, and when the voltage got to 10.9 volts I started getting all kinds of error messages. I swapped out the alternator in the parking lot of Autozone, and it's been rock sold 14.5 volts ever since...

silvrhand

Severe low voltage will create a mirage of issues if your alternator is going out, if you have headers as well then you are also likely cooking your starter slowly but surely.

I just went through this a while ago.

- new battery
- new alternator
- new starter

I drove to Austin came home and the battery low kicked on, running at 2k RPM's I was getting about 11v on the alternator, running at 4k rpm I was getting a little above 12.5v. I was luckily close to home and just rode home in a lower gear till I could get it changed.

Then it wouldn't start, so the starter apparently cooked itself and I had to replace it as well even though my headers are coated I could see after the headers were installed how close the solenoid was, so as I was replacing it I added a heatshroud to the alternator.

Now that being said I have a spare 170A Billet Tech alternator that is new, the first one they sent me was bad, and I ordered a black one as I didn't like the polished one, you ban pick up a nice new alternator for a good price

Rupert pupkin

Pb82 Ronin

When this happened to me it was a broken starter post. Thankfully even with headers, it wasn't too bad of a fix.

WhiteDiamond

Had the "service charging system" a few weeks back. Battery didn't measure good, so replaced it. Drove it somewhere and came out to a dead vehicle in about a 20-30 minute time frame. Voltage regulator on stock alternator culprit. Just spent the bucks and went the Billet Tech unit advertised here https://www.corvetteforum.com/forums...ght=alternator

Works awesome. Solves the GM OEM alternator issue.