The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Re-wire truck or???

**hatzie** · 09-07-2016, 02:19 AM

The stock charge wire on the LS1 F body is 6AWG. 6AWG will carry 100amps just fine. That should be plenty.
http://www.powerstream.com/Wire_Size.htm
Yes the alternator is MAX rated for 105-145amps but it rarely will run more than 2/3 of the rated current. The battery and alternator will not last long if you are pulling close to 100% rated output continuously. They aren't designed for that.

The first thing I'd do is break out your good meter and run some static voltage drop tests to isolate which cable is causing the problem.
Check from the battery to the engine block circuit and the battery to the alternator BAT circuit with the ignition on and engine off. If you have larger than .1vdc drop then try to isolate which connection is loose by testing at each connection point running back toward the battery. I bet you'll find a dodgy cable or loose/corroded connection. Fix em and you'll have a more stable charge.
#2 would be to make sure the Sense lead to the alternator regulator connection or the PCM is making good contact at each end and is not damaged or spliced in some dodgy fashion.

09-07-2016, 02:19 AM	#5
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,020	Re: Re-wire truck or??? The stock charge wire on the LS1 F body is 6AWG. 6AWG will carry 100amps just fine. That should be plenty. http://www.powerstream.com/Wire_Size.htm Yes the alternator is MAX rated for 105-145amps but it rarely will run more than 2/3 of the rated current. The battery and alternator will not last long if you are pulling close to 100% rated output continuously. They aren't designed for that. The first thing I'd do is break out your good meter and run some static voltage drop tests to isolate which cable is causing the problem. Check from the battery to the engine block circuit and the battery to the alternator BAT circuit with the ignition on and engine off. If you have larger than .1vdc drop then try to isolate which connection is loose by testing at each connection point running back toward the battery. I bet you'll find a dodgy cable or loose/corroded connection. Fix em and you'll have a more stable charge. #2 would be to make sure the Sense lead to the alternator regulator connection or the PCM is making good contact at each end and is not damaged or spliced in some dodgy fashion. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 09-07-2016 at 02:28 AM.