Factory Grounds. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HarrisonTX · 11-15-2010, 02:25 PM

What do these trucks need as far as a ground system?

I just have a factory size ground wire going from the (-) on the battery, directly to a frame rail. And a small ground strap going from the firewall to the the back of a cylinder head. This seems insufficient.
The PO had a 4x4 shop (oh God) install a crate motor.

The truck cranks over very slow, and sometimes not at all. It'll just bump over sometimes. Its not a weak battery, although it maybe a weak battery.

I've also just seen one from the battery to the frame, and from that same location on the frame, to the block.

Truck's an '86 k5, with a 350.

3r!c84 · 11-15-2010, 02:51 PM

im thinking about this too.. mine go's too the battey - to my engine block. and only has 1 ground strap to cab to engine

Manbearpig · 11-15-2010, 03:06 PM

lol I have 1 gauge ground cables going to my core support and my frame
also have a 1gauge positive cable going from my battery to my alternator

Overkill but WIN

Jonboy · 11-15-2010, 03:09 PM

I was having ground issues with my '79 also. A ground cable to the engine fixed it.

rare86 · 11-15-2010, 03:11 PM

all of mine have the main battery ground to the engine itself, mostly the alternator mounting bracket. Most of the amp load goes thru the starter, which is grounded to the block, so you want this one to be the biggest. There is one from the back of the head to the firewall and one fromt the battery negative to the core support. If you dont have an adequate ground to you block for the starter, it will cause a voltage drop and your starter will crank slowly as indicated. Not saying this is your problem, but worth looking in to.

HOGDADDY · 11-15-2010, 04:52 PM

I believe this is a factory ground pictured also.

Dru · 11-15-2010, 05:30 PM

My 86 is setup close to what rare86 said about his.

Have a 77 Vette that I had a bad ground on, and also ran into a string of crappy starters, it just melted the cable right out of the lead ground lug one day.

3r!c84 · 11-15-2010, 05:27 PM

Yes it is
Posted via Mobile Device

*78 Chevyrado* · 11-15-2010, 05:59 PM

When I put on my hi-amp alternator I added some extra grounds just for the heck of it. The OE ground strap from the engine to cab was still good and still had a great connection so I left it alone.

My battery negative cable still goes to the alternator bracket like stock, but I added these. They are 6ga I think. I had this lying around the house so I stuck it on there.

Engine to Frame

Cab to Frame. I used an unused preexisting stud on the cab brace for the master cylinder.

Another for the heck of it, I checked to see how many AMPs each wire was pulling, and the stock strap showed only 3A or 4A running through it, while each of my new additional ground cables showed around 30A each running through them.

11-15-2010, 02:25 PM	#1
HarrisonTX Registered User Join Date: Nov 2003 Location: Waco TX Posts: 247	Factory Grounds. What do these trucks need as far as a ground system? I just have a factory size ground wire going from the (-) on the battery, directly to a frame rail. And a small ground strap going from the firewall to the the back of a cylinder head. This seems insufficient. The PO had a 4x4 shop (oh God) install a crate motor. The truck cranks over very slow, and sometimes not at all. It'll just bump over sometimes. Its not a weak battery, although it maybe a weak battery. I've also just seen one from the battery to the frame, and from that same location on the frame, to the block. Truck's an '86 k5, with a 350. __________________ '69 custom/camper '74 260z 302 chevy/tko500 swap in progrss '79 Malibu 355 all forged 4 speed car. '86 k5 blazer '06 Duramax

11-15-2010, 02:51 PM	#2
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: Factory Grounds. im thinking about this too.. mine go's too the battey - to my engine block. and only has 1 ground strap to cab to engine __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

11-15-2010, 03:06 PM	#3
Manbearpig Registered User Join Date: Mar 2009 Location: Midland, Tx Posts: 418	Re: Factory Grounds. lol I have 1 gauge ground cables going to my core support and my frame also have a 1gauge positive cable going from my battery to my alternator Overkill but WIN __________________ 1972 GMC C10 Last edited by Manbearpig; 11-15-2010 at 03:07 PM.

11-15-2010, 03:09 PM	#4
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: Factory Grounds. I was having ground issues with my '79 also. A ground cable to the engine fixed it. __________________ 1974 Jimmy- 5.3/4L80e/NP241

11-15-2010, 03:11 PM	#5
rare86 Extended cab fanatic Join Date: Oct 2009 Location: Gardendale, Tx Posts: 314	Re: Factory Grounds. all of mine have the main battery ground to the engine itself, mostly the alternator mounting bracket. Most of the amp load goes thru the starter, which is grounded to the block, so you want this one to be the biggest. There is one from the back of the head to the firewall and one fromt the battery negative to the core support. If you dont have an adequate ground to you block for the starter, it will cause a voltage drop and your starter will crank slowly as indicated. Not saying this is your problem, but worth looking in to. __________________ If it has a motor, it has my attention.

11-15-2010, 04:52 PM	#6
HOGDADDY Registered User Join Date: Jul 2006 Location: Alabama Posts: 661	Re: Factory Grounds. I believe this is a factory ground pictured also. Last edited by HOGDADDY; 11-15-2010 at 04:53 PM.

11-15-2010, 05:30 PM	#7
Dru Registered User Join Date: Oct 2010 Location: Wichita, Ks. Posts: 89	Re: Factory Grounds. My 86 is setup close to what rare86 said about his. Have a 77 Vette that I had a bad ground on, and also ran into a string of crappy starters, it just melted the cable right out of the lead ground lug one day.

11-15-2010, 05:27 PM	#8
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: Factory Grounds. Yes it is Posted via Mobile Device __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

11-15-2010, 05:59 PM	#9
78 Chevyrado Account Suspended Join Date: Dec 2007 Location: Unnapreciative, Trollville Posts: 2,079	Re: Factory Grounds. When I put on my hi-amp alternator I added some extra grounds just for the heck of it. The OE ground strap from the engine to cab was still good and still had a great connection so I left it alone. My battery negative cable still goes to the alternator bracket like stock, but I added these. They are 6ga I think. I had this lying around the house so I stuck it on there. Engine to Frame Cab to Frame. I used an unused preexisting stud on the cab brace for the master cylinder. Another for the heck of it, I checked to see how many AMPs each wire was pulling, and the stock strap showed only 3A or 4A running through it, while each of my new additional ground cables showed around 30A each running through them.



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