First Gen. Ground Strap Question

[Bronco648]

Ranger: 1985 RCLB 2.8/auto

I am putting this truck back together (after the p.o. removed the drivetrain). I have this ground cable:

It measures ~25.5" from eye-to-eye and is the same gauge as the ground cable that goes from the battery to the radiator support (see Figure 3 below). The big eye sure seems like it would fit perfectly under a starter bolt. But, I have no idea where it goes, or what it would attach to, with (what appears to be) a sheet metal screw.

My Electrical & Vacuum Trouble Shooting Manual indicates that the ground cable runs from the battery to the starter (see Figures 3 & 5):

But, the O.E. ground cable (which has been swapped out for a new cable of the same length) was not long enough to reach the starter. The ground cable attaches to the passenger side of the block, near the oil filter mount.

Does anyone have any idea where the cable in the top pic is supposed to go?

TIA.

 

[RonD]

There are 4 main grounds

Bigger negative battery cables goes to engine, as said usually starter motor bolt but block is OK, because starter and alternator use or generate the most AMPs, so need the larger cable

2nd is Rad support and inner fender, headlights, horn and relay grounds

3rd is Cab ground, usually from back of head to firewall, wiper motor bolt was popular firewall ground, for cab electrics

4th is frame ground, taillights, park lights sometimes fuel pump

Cab often had a ground strap under it to frame
Also bed to frame ground strap

That longer, smaller gauge wire, could be used from Block ground(big cable) to upper firewall for the cab ground

If your negative battery terminal just has the one larger cable, then use a ground strap from block ground to frame
And from frame to rad support and inner fender
(later model negative battery terminal cable usually had 1 larger cable then 2 smaller wires, smaller were for rad support/inner fender and then frame)

You CAN have 1 too few grounds, but NEVER 1 too many, lol

Frame and body parts are painted FIRST, then assembled, so no good grounding between them or the body parts, bolts holding them together are on clamping painted surfaces and often rubber mounts to frame
Engine and trans sit on rubber mounts also not good for ground to frame or body

 

[Bronco648]

Thanks @RonD !

As mentioned, the negative battery cable goes to the block near the oil filter base. However, I have seen some of these ground cables with a brass Adel clamp in the middle which bolts to the passenger frame rail near the motor mount. I may make this modification to my new ground cable.

The radiator support seems to have grounding points on both sides of the radiator but I'm not seeing actual wires that ground the inner fenders. I may not be looking hard enough.

I do see the engine to firewall ground strap which is braided. The wiper motor has a small wire which runs to that point on the firewall.

The taillights ground point is back near the back bumper. I do not have an electric fuel pump (mechanical only). I know you've mentioned that the filler neck should be grounded (I checked my filler pipe and that does not have a grounding strap.

Interestingly, my exhaust y-pipe has a braided grounding strap that runs to the cab (or maybe the frame, it's hard to see where it goes).

When I replaced my cab isolator bushings, I did not notice a cab-to-frame strap nor is there a bed-to-frame strap (I removed the bed to pressure wash it and the top of the gas tank).

So, yes, I need to add some.

 

[RonD]

Yes, on older Fords they liked to do Main ground cable with an "eyelet" in the middle to ground the frame and engine with the one larger cable
But it became more cost effective to just use 1 larger cable to engine then smaller ground straps/wires to share that ground

In older models with 3 wire O2 sensors the exhaust pipe needed a reliable ground for O2's internal heater
Later models had 4 wire O2's

Rad support and inner fenders usually had short ground straps in upper corners, then either a direct wire to battery negative or on one side a ground to frame down low

Odd there was no bed ground strap, that's the filler ground, as its bolted/screwed to bed metal

 

[Bronco648]

I opted to install that 'eyelet' into the new ground cable so that the block and frame are grounded directly to the battery. Still trying to figure out where that one ground cable goes (pic posted in my o.p.).

My truck has no emission controls anymore so I completely forgot about the O2 sensors. It makes sense that the y-pipe would be grounded then.

Rad support (passenger side of the rad) is tied directly to the ground post on the battery. I'm going to have to look harder for the inner fender grounding points.

The bed has direct contact with the frame but we know that rust is not a good conductor. Of course the bed bolts are galvanized and clean so maybe I'm getting away with that because the truck isn't rusty. Adding a ground strap to the bed is trivial. I'll buy one of those braided brass ones for that.