LS1 alternator problems

**Shmack2004** · 04-25-2011, 12:09 AM

I've burned up 5 alternators and I dont know why. the wiring seems but but the volt gauge on the dash reads almost at 18 volts.

any idea as to what could cause this?

**Smittro** · 04-25-2011, 03:00 AM

What car? Is your 87 camaro an LS1 swap?

If so sounds like something maybe wired incorrectly..

More info needed...

**Smittro** · 04-25-2011, 03:03 AM

Oh and Welcome to LS1.com..

**KMdef9** · 04-25-2011, 09:17 AM

Agree, more info is needed.

Are you running a sound system? Does your sound system have a multiple batteries to it?

Is the voltage regulator getting replaced with the alt? Are the alts used? Re-manufactured? Brand new?

**Shmack2004** · 04-25-2011, 02:38 PM

yea its swapped, 87 camaro with a 99 camaro ls1 drivetrain. The wiring is fine i cant find any issues there, the alt turn on wire reads 10.2 volts like it should...im stumped on this one. i went through 3 remans and 2 new alts. no sound system except for a sony head unit and 2 speakers.

**waterman74** · 04-25-2011, 03:10 PM

Check engine grounds and chassis grounds for corrosion or missing.There may be high resistance in system..

**Shmack2004** · 04-25-2011, 05:26 PM

so all i found online anywhere says that wire should only get 5 volts...so why the hell is mine getting 10.2 volts?

**waterman74** · 04-25-2011, 08:07 PM

Do you have a 470ohm resister in the small red wire?

**Shmack2004** · 04-25-2011, 09:59 PM

Originally Posted by waterman74

Do you have a 470ohm resister in the small red wire?

no i used the whole 4th gen harness and i was told i wouldnt need it, if i do i'll put one in if that will fix the problem

**Shmack2004** · 04-26-2011, 12:22 PM

well the resistor did'nt help anything

**sjsingle1** · 04-26-2011, 12:29 PM

is it a built harness........or pulled from a car harness?

**Shmack2004** · 04-26-2011, 01:05 PM

pulled from a 99 ss

**ThunderChicken** · 04-26-2011, 02:57 PM

Check your starter. Could be pulling too much voltage.

**waterman74** · 04-26-2011, 03:08 PM

How many wires on voltage regulator plug??

**Shmack2004** · 04-26-2011, 06:23 PM

how could the starter be doing that when its only used to start the car?
it only has 1 wire in the plug

**Cutlass** · 04-26-2011, 07:35 PM

Originally Posted by Shmack2004

so all i found online anywhere says that wire should only get 5 volts...so why the hell is mine getting 10.2 volts?

I think the L terminal should have 12 volts from the PCM. Maybe you have a bad PCM

**Shmack2004** · 04-26-2011, 07:42 PM

Originally Posted by Cutlass

I think the L terminal should have 12 volts from the PCM. Maybe you have a bad PCM

i thought that too but it did the same thing in the 99 before i pulled it. im not using the PCM from that car either. this is the most irritating problem i have ever had

**waterman74** · 04-27-2011, 05:30 AM

per alldata trouble shooting on charging systems 1999 camaro (quote)

The L terminal must be a resistance circuit eather through a charge indicator or the PCM. If direct battery voltage is applied to the generator at the L terminal, the regulator will eventually be destroyed,causing repeat failure.

AGAIN, check all engine grounds and B+ connections on alternator completly through to the battery for corrision and make sure they are tight.

**Cutlass** · 04-27-2011, 06:00 PM

Originally Posted by waterman74

per alldata trouble shooting on charging systems 1999 camaro (quote)

The L terminal must be a resistance circuit eather through a charge indicator or the PCM. If direct battery voltage is applied to the generator at the L terminal, the regulator will eventually be destroyed,causing repeat failure.

AGAIN, check all engine grounds and B+ connections on alternator completly through to the battery for corrision and make sure they are tight.

Oops yep your right. I found that info in the service manual also.

Shmack2004, you need to trace your wiring and figure out why you have 10 volts on the alt L terminal. What PCM are you using?

**Shmack2004** · 04-27-2011, 10:32 PM

i've checked all the power and ground wires, they are all tight and not corroded. i traced the red wire back to the PCM and its fine. The PCM is model number 12200411. this is really blowing my mind