The fix for my endless alternator failures by 00pooterSS

4 minute read

The fix for my endless alternator failures 

Compliments of 00pooterSS @ https://ls1tech.com

5-31-2010

I posted a thread a while back about having alternator after alternator fail, one literally lasted about 5 minutes. 

Long story short I tested every thing multiple times and even replaced the exciter wire and connector, never could find an issue and it all started when I replaced the factory original alternator with an aftermarket one, and it was all downhill from there. 

The fix.... A truck alternator. I got the idea from another board member that the truck alternatoractually fits the F body cars, so I went to the junk yard and spent $40 on a used 2003 Truck 145 amp alternator bolted it in and the voltage has never been more stable.

The 145 amp truck alternator only has one simple modification that needs to be made to use it, it does not use the rear support bracket that the F body alternator does so remove the one bolt and bracket, other than that it bolts directly in, plugs directly up, and works good!! So for less money you can have an higher amperage output, more stable, more durable alternator if you go this route. The pulley was even the same, this couldn't be easier.

I am going to add a wire from the back of the alternator to the battery to help carry the extra amperage since it has been stated the factory wire isn't even enough for the puny stock alternator.

I hope this helps anyone else with the same issues, here is the link to my original thread if you feellike reading more details of the problems I was having

https://ls1tech.com/forums/generatio...ders-here.html

Identifying the right alternator:Get a 99-2003 Truck alternator (may even apply to up to around 2005?), 145 amp, 4 pin connector, the code junk yards use to identify it is "KG3". The standard truck alternator is a 105, Escalades and such trucks with a lot of electronics use the 145. When I ordered mine I told them it was a 2003 truck, 145 amp, 4 pin connector, KG3 option and they figured it out. I got mine from LKQ for $43.30 picked up.

Some more info on identifying the alternator

ALSO VERY IMPORTANT Replace the alternator connector, the single wire connector with the plastic plug in on the top, these fail and cause problems as well. Here is some information on the connector.

AC Delco part PN# PT1136 (Oreilly has another brand also for the connector, don't remember the name brand)

I got mine from NAPA so you can try going there or go to Oreilly. They are all over Ebay too, search LS1 alternator connector.

http://www.oreillyauto.com/site/c/se...aro&vi=1361450

I dont have pics but may be able to take some in a bit when I get home...

And im glad you posted up, I had given up hope until you gave me the idea to do this so I wanted to thank you for ending that nightmare!! I may still go that route you suggested but for right now this is working great.

I thought I would have to move the sway bar or fans since the stock one is hard enough to get around those things but I was still able to work this big honking thing through and into the hole. I was amazed at how easy it was and how well it worked.

All my rebuilds would go below 13 volts within about 20-30 minutes ESPECIALLY if I was running the system, and they would either way with the a/c on and it was hot sitting at idle. I have gone on 3, 100 mile or more trips in the past 2 weeks with a/c, headlights, system, everything on all the way and its steady right at 13...