66 F100 Ground question

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Nov 20, 2012 | 01:10 PM

thumper7741

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66 F100 Ground question

I am new to FTE but WOW what alot of info out there! I am chasing a ground gremlin, and would to ask for some help.

While chasing down my battery ground it appears to be attached to some type of flange type thing that is attached between the exhaust manifold and the head??? is this normal? also the ground does not have any insulation areoud it near the attach point.

I tried to jump the truck connecting the + and - to the good battery and the + to the dead battery and the - to the truck chassis. the 4 gauge cables were extremely hot in the span of 15-20 seconds.

I have also had the starter bench tested and it is fine.

any ideas.

thanks in advance.

Nov 20, 2012 | 03:15 PM

SuperSabre

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From: Tucson, Arizona

You didn't specify which engine your truck has. If it's a 352, the stock battery ground cable mounts to the front SIDE of the engine block, just below and behind the alternator. I've forgotten what size the bolt is, but it's bigger than you'd expect and requires an oversized lug at the end of the cable. There is also an engine to body ground at the back of the block that mounts to the firewall. Plus any other grounds you decide to add. When it comes to grounds, more is better. Make sure both ends of your ground are contacting clean, bare metal - no paint or rust. If your engine is an I 6, someone else will have to help you. Good luck!

Nov 20, 2012 | 03:20 PM

SuperSabre

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From: Tucson, Arizona

My response was for a 4 x 2 truck. 4 x 4 trucks may be different.

Nov 20, 2012 | 03:50 PM

thumper7741

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Thanks SuperSabre, btw it is a 352, 4X2. would the ground cause the jumpers to heat up like that?

Nov 20, 2012 | 04:02 PM

thumper7741

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I just checked again and the main ground is attached to a large lug that is sandwiched between the exhaust manifold and the head on the pass. side of motor. i have never seen anything like that before.

Nov 20, 2012 | 05:22 PM

jowilker

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From: Creedmoor, North Carolina

I have only had success going battery post to post. That gives you the most direct current flow. This is not say that it won't work.

It can also help to have the vehicle running with the donor battery.

John

Nov 20, 2012 | 06:01 PM

SuperSabre

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From: Tucson, Arizona

I agree with John about hooking up jump cables. Wires get hot because they are asked to carry more amps than they were designed for, or there is a dead short circuit. I am not an expert electrician by any means but if you're getting hot wires I'd be looking for a loose connection (which may raise the current draw) or a wire that is supposed to be positive but is touching something metal (short to ground). Good luck.

Last edited by SuperSabre; Nov 20, 2012 at 06:03 PM. Reason: left out a couple of words