The car is a 2002 LS1 Camaro

After installing a new set of Spec D tuning ebay headlight to replaced my broken factory ones, I was aiming the headlights on the car with the engine off and boom after about 30 minutes the car is completely dead in an instant - to the point not even the interior lights flip on...ok that's maybe to be expected.

I boost the car and the battery cables smoke a little bit and get hot as hell...weird...car starts and ends up dying at idle about 5-10 minutes later...no biggie, pull it in the driveway and put the trickle cell charger on it. Battery goes from "dead" and zero response from electronics to showing 100% charged in about 10 minutes...weird but whatever ok... cars sits for 2 weeks and still fires up...when driving the volts seem to be dropping into the red area of the gauges.

Sooo.. I grab the voltmeter and I verify after letting the car sit over night - battery shows 12.4 volts across the terminals.

Key on engine running it was showing 13.1-13.3 volts...so I believe the alternator to be junk. Call the scrap yard and pick up a truck alternator as a replacement and pop that in... start the car up and it shows 13.8 volts...after a drive and a retest it shows 13.1-13.3 volts at idle...if you rev the car in neutral I drop to about 11.xx volts above 3,500 rpm. If I enter the highway and go WOT by the time I hit 80mph my check gauges light is on and I am buried in the red on the volt gauge.

So I think maybe it is the exciter wire- pull that plug off this morning and I got 9.78 volts going to that plug with the engine running and it unplugged from the alternator.

So I am stumped...battery shows good, exciter wire I think is good, they tested the alternator and said it was good? What the heck could be wrong?

 

Check for a short on the charge wire from the alternator to terminal block.
Check the big fuses under the hood.
Clean battery terminals?

Just thinking..

 

The charge wires looked good to me - I just ran all brand new wiring with 4gauge wire about 2 years ago from the battery to the starter, alternator and fuse block. I also upgraded the ground wire at that time as well.

The battery terminal looked pretty clean but I ran some sandpaper across the touch points anyways to make sure all was well and it didn't change anything.

As far as fuses - those I haven't checked...which are you thinking? Generally when a fuse is bad something doesn't work entirely, not intermittently?

oh - also I should mention, I just did a road trip down to CT which is about 500 miles... anything over 70mph and the battery gauge would jump up and down from 13v to red every 5 seconds...if I sat at 65-69mph she seemed fairly happy ...which I also found to be very weird and had me really thinking the exciter wire was damaged...but I am getting 9volts from it?

 

is there anything else I can test?

 

Sounds like a speed control device to me.


Just kidding on the speed control, so this all started after your headlight conversion? I don't know the kit your using, but I'd go back and investigate and eliminate the headlights assemblies. A short or defective part could be messing you up.

 

I unplugged the headlights to see if that made a difference and it did not, so I believe it is likely coincidence as I drove without them plugged in and was still having the same issues.

After confirming that, I wired up a new exciter wire and my voltage bumped up at idle after a drive and test to about 13.48-13.5volts at idle with the fans on...when the fans kick off I have approximately 13.63-13.65 volts

However, I still drop voltage at WOT or any throttle above 3000rpm, just not as much as before with the new exciter wire.

I intend to target all of my major grounds this weekend...but can anyone think of anything else or anything I can test?

 

If you had an exciter wire problem, you'd have issues at idle.

If you have this issue as RPM's go up with the car in neutral, I'd first check for a slipping belt. Maybe you have a bad/loose belt? How is your tensioner? Is your belt routed correctly?

 

The belt is routed correctly (I triple checked) and I installed a new kaltech manual tensioner to eliminate any belt slip just in case.

the exciter wire had 3/7 strands broken on it and does appear to be acting better with the new wire...but still not 100%.

 

So I pulled off all the grounds I could find, sanded them down, cleaned them up. I pulled out the ground strap from behind the alternator and it was full of green corrosion. I replaced it with some spare 4gauge wire I had lying around.

Fire the car up and I get 14.xx volts on cold start- great I think it’s fixed... go to back out of the driveway and I can see the volts dropping... go for a drive and anytime I am above 2500 rpm the voltage is in the red. If I put the selector in 2nd gear and drive above 2500rpm for 5-10 seconds my check gauges light will come in due to low voltage.

I am stumped- is it back to being the alternator? Is there another way to test things?

 

This may sound stupid, but I know you said you cleaned up the grounds. Do you mean you cleaned up where they attach to the body as well??

With all you have said so far I am getting fairly stumped as well.

 

not stupid at all- I cleaned up anywhere where I saw a ground, so battery terminal, spot above the battery on the body, points along the frame, the block where the ground strap goes behind the alternator and the body connection point. Some grounds only got one side cleaned like the small wires on the front frame- no clue where the other side of those go unless I tear apart the entire harness and I am guess they will end in some of the electronics.. but in all honesty I wasn’t seeing dirty spots on the grounds I took off (minus the one ground strap)- I just ran some sandpaper to be safe.

If I have to get the junkyard truck alternator rebuilt I will- but I would like to be sure it needs it and be sure I am going to fix the problem before this becomes a money pit problem

 

When you swapped to the new headlights, did you disconnect the battery from the car?
Have you tried with another battery?

 

What about Neutral for 5-10 seconds at 2500+ RPM?

If that is good, then that would indicate your grounds and alternator are fine. We have had folks with problems where the air moving in the engine compartment and bumps in the road cause wires to become disconnected. (Loose power cable lugs (the crimped ones), bad battery cables, etc.)

 

So at 2500 rpm in neutral I have voltage drop as well- anytime above 2500rpm - neutral, 1st, 2nd, D it drops and the red check gauges light comes on if I keep it above 2500 rpm for 8-10 seconds.

I have now had the battery tested at the parts store- the voltage was ok in the 12.2-12.4 range (did 3 tests) however the CCA’s were 450 of 800 that it was supposed to have. So they advised the battery was no good. So I replaced it under warranty but am thinking I still need the alternator rebuilt... correct me if I am wrong CCA’s should only affect cold starts not voltage of the vehicle when it is running? Especially since theoretically you should be able to unplug the battery and run the car off the alternator only when it is started?

Also yes- I unplugged the batter when installing headlights

 

It's definitely not your battery because it doesn't change with RPM.


This problem may have stressed it out. A reconditioning may have brought it back - but a warranty replacement is hopefully less expensive than the machine.


Correct. The battery starts the car and does a little to condition the power of the running car, but that's about it. The alternator feeds the running demand and provides extra power to charge the battery back up.


This sounds like a problem at the alternator. Not enough information to determine if it's the alternator, yet. Have you had the alternator tested?

When you stop revving the engine, do the volts come back up?

 

The junkyard tested it and said that the unit they gave me was good (I was having the same problem with my stock alternator which is what prompted the change to a Junkyard unit)

The volts do go back up when you stop revving the engine above 2500rpm- so driving on the highway I went 500 miles doing 65 and the car was fine- kick it up to 70-75 where roms are over 2500 and the voltage would drop up and down constantly every 1-2 seconds. Kick up to 80+ and it was a straight drain no recovery of volts unless you get off the throttle.

I am going to take the alternator to a rebuild shop this afternoon but I am still stumped

 

That sounds like a bad alternator or a belt issue. If you take the alternator to a parts store to be tested, the used parts place should give you your money back if it's indeed bad.

 

Not sure how the junk yard tested it, but most Autozones, etc. have a machine to bench test them on. Sometimes it is a bit of a pain because you have to uninstall and bring it in, but it's worth it to check before having it rebuilt. A rebuild shop would likely tell you "yes, it needs to be rebuilt"

 

if you haven't already, check the power wires from battery, to starter, to fuse panel, to alternator.

I had an issue where the main power cable that run under the radiator to the driver side (to alternator and fuse panel) brock off the wire holders and the cable got chewed up by the crank pulley. it still worked, but dirt and mud got into the open insulation and caused voltage issue.

I upgraded to big 3 when I replaced the main power harness.

 

so got back from the alternator shop and this is the outcome:

Bench tested the junkyard truck alternator and he believes it to be good - proper charge at idle (14.6-14.7) - however he could not apply a load to the alternator due to some machine issues. He opened it up and the alternator was a rebuild in the past - but appears to have full brushes. He said the only thing he could see being wrong with the alternator is possibly the rotor is stuck open.

Bench tested the stock alternator - tested good - opened it up and found the brushes were worn all the way down however the guy said although the alternator is "junk" it wasn't displaying black marks on the slip rings indicating that I should be having the type of problem I am having.

He believes my problem is on the car as opposed to the alternator and his theories are as follows:

1) wiring (however I just ran all 4 gauge wiring from the battery to alternators/starter about 1.5 years ago and it all appears to be in great shape. I also replaced the exciter wire eliminating that.

2) belt slip - however, this problem existed both with the factory tensioner as well as I installed the katech manual tensioner - I see no evidence of belt slip

3) He has asked if the harmonic balancer has separated from the crank pulley causing the crank to spin but the alternator not to spin as fast as it needs to. I plan on marking the pulley right across with white out to see if I have movement...I am doubting this scenario because I am not experiencing overheating and I would imagine that the water pump would spin much slower if this were the case as well.

I also took a modified jumper cable to connect to the back of the alternator directly to the battery and I am to take a ground cable and put it directly to ground from the alternator casing to ensure that wiring is taken entirely out of the equation.

I honestly think there is a very slim chance it is either of the two scenarios (wiring since it is new or pulley slip) ...so short of this I suppose the next step is replace the alternator but I am completely stumped.