Engine Compartment - Routing of wires & hoses, etc.

[Bronco648]

OK, I'm getting close to having the my '85 RCLB re-assembled. However, because I didn't disassemble this truck, I'm a little lost as to how wiring and hoses are routed in the engine compartment.

First Question: How does the starter cable run to the starter?

I ran the red cable, from the starter relay, down and under the very front of the oil pan and then back to the starter along the driver's side of the oil pan. Is that correct?

Second Question: How does the ground cable run to the starter?

When I got my truck the ground cable was in poor condition so I replaced it with another 4 gauge cable that's ~2 inches longer. It originally had a brass Adele clamp that was soldered to the wire (sheath stripped) and the clamp was bolted to the outside of the frame just below the trailing edge of the battery tray. My Electrical & Vacuum Trouble Shooting Guide shows that a grounding cable goes to the bottom bolt of the starter (G104 for those with an E&VTSG). But the battery cable isn't long enough to reach the starter. Where does the negative battery cable go and how does it tie into the starter?

TIA

 

[RonD]

If cable is long enough then around the front of oil pan is fine just put some wire loom around it so it can't chafe, and short to any metal

You can use a short Negative cable to engine block, i.e. motor mount bolt
Starter and Alternator are grounded thru engine metal, neither has a specific ground terminal just grounded thru their metal cases

If starter was on the same side as battery then negative cable would be hooked to starter motor's bolt to bell housing, because its easy

On some the Negative cable runs under the engine and grounded to Frame(cross brace) and then continues on to starter motor bolt, they look like this: https://i.ebayimg.com/images/g/3ZoAAOxy4dNS7Co2/s-l500.jpg

Engine and trans are on rubber mounts
So Frame and body all need their own Ground straps

 

[Bronco648]

If cable is long enough then around the front of oil pan is fine just put some wire loom around it so it can't chafe, and short to any metal

Already covered in that black plastic loom protection! I might be able to use that hard heater core/coolant line, that runs in the same area, for support.

You can use a short Negative cable to engine block, i.e. motor mount bolt
Starter and Alternator are grounded thru engine metal, neither has a specific ground terminal just grounded thru their metal cases

If starter was on the same side as battery then negative cable would be hooked to starter motor's bolt to bell housing, because its easy

I'll see if I can't find a convenient, unused, tapped boss on the block for the negative battery cable. I can then ground the starter motor to the frame and make sure the frame is connected to the negative battery terminal.

On some, the Negative cable runs under the engine and grounded to Frame (cross brace) and then continues on to starter motor bolt, they look like this: https://i.ebayimg.com/images/g/3ZoAAOxy4dNS7Co2/s-l500.jpg

That is almost exactly what was in the truck when I got it. However, the insulation had cracked in several locations exposing the copper strands. It was only a matter of time before the 'green crusties' did their dirty work.

Engine and trans are on rubber mounts
So Frame and body all need their own Ground straps

I noticed that there seem to be ground straps everywhere. I have the one on the firewall fastened to the driver's side cylinder head. The negative battery cable grounds to the radiator support and I need to make up for eliminating the ground connection to the frame, that I mentioned in the OP. There's even a ground strap for the Y pipe, which surprised me a little.

Thanks for the info!

 

[RonD]

The bed should also have a ground strap to frame, so no spark when filling up

Body parts and the frame are all painted BEFORE assembly, and most have rubber grommets between them, lol
So when in doubt GROUND IT OUT

You can only ever have one to few ground straps, never one too many

 

[Bronco648]

The bed should also have a ground strap to frame, so no spark when filling up

I've had the bed off and do not recall disconnecting a ground strap. Any idea where it's supposed to be?

Body parts and the frame are all painted BEFORE assembly, and most have rubber grommets between them, lol
So when in doubt GROUND IT OUT

I've read this and am guessing that has to do with 'ease of production' on the assembly line. I'll have to make sure all the grounds are clean/good.

You can only ever have one to few ground straps, never one too many

 

[rumblecloud]

I've had the bed off and do not recall disconnecting a ground strap. Any idea where it's supposed to be?

Here's a shot of where mine is:

 

[Bronco648]

Moving on to fuel lines; how about a shot of how the fuel pump is connected to the hard line from the tank and the (hard/soft) to the carb?

 

[rumblecloud]

Sorry can't help with this one.------- what's a "carb?"
Too many will put unnecessary weight on you

 

[Bronco648]

Sorry can't help with this one.------- what's a "carb?"
Too many will put unnecessary weight on you

 

[4x4prepper]

> Second Question: How does the ground cable run to the starter?

On my 1985 B2, besides the ground wire to the block, there is one going to a stud under the battery tray on the frame, which holds the cable going to the block. Basically the cable is stripped, attached to the frame with a bracket (this grounds the frame) and then the cable continues and grounds the block.

 

[Bronco648]

> Second Question: How does the ground cable run to the starter?

On my 1985 B2, besides the ground wire to the block, there is one going to a stud under the battery tray on the frame, which holds the cable going to the block. Basically the cable is stripped, attached to the frame with a bracket (this grounds the frame) and then the cable continues and grounds the block.

Yep, I had that, too. I didn't know that you could get replacement ones so the one I now have doesn't ground the frame. I'll deal with that with a separate wire.

Courtesy of @RonD

 

[RonD]

Generally speaking vehicles need 5 main grounds

Larger cable from battery Negative to engine block, for starter motor and alternator, the largest AMP passing cable

Smaller wire/strap to
Rad support, headlights and horn
Frame rail, tail lights, fuel pump
Inner fender, relays
Firewall, cab electrics, usually found on the back of drivers side head to firewall(wiper motor bolt was often used)

In pickups the bed is often grounded to the frame as well, this is because fuel filler is usually on the bed side, so for safety, no sparks, lol


People often forget or don't realize that electricity must travel in a "circuit"(circle)
So in the case of DC it travels from +(12v) to -(ground)
(actually the opposite but no need to learn that, lol)

If the 12v wire can handle 10amps but the ground wire can only handle 5amps then 5 amps is the maximum this "circuit" can pass
So grounds are the same importance as 12v side, exactly the same
Either one being corroded or limited in power passing reduces power in the whole "circuit"(circle)

 

[Bronco648]

Generally speaking vehicles need 5 main grounds

1 - Larger cable from battery Negative to engine block, for starter motor and alternator, the largest AMP passing cable - check

Smaller wire/strap
2 - radiator support: headlights and horn - check
3 - Frame rail: tail lights & fuel pump - check (not in my case for the fuel pump, it's mechanical)
4 - Inner fender: relays - need to look for this
5 - Firewall: cab electrics (usually found on the back of drivers side head to firewall [wiper motor bolt was often used]) - check

In pickups the bed is often grounded to the frame as well, this is because fuel filler is usually on the bed side, so for safety, no sparks, lol - I do not see a ground strap on the filler neck hose, like you posted earlier. My bed is not isolated but makes direct contact with the frame. However, that's not the best grounding method and I'll probably add a grounding strap to mimic yours.

Additionally, I have (o.e.) grounding straps for the hood and exhaust (Y pipe).

 

[Bronco648]

Moving on to fuel lines; how about a shot of how the fuel pump is connected to the hard line from the tank and the (hard/soft) to the carb?

I called Carter and they told me that the barbed connection, on the (mechanical) pump, is inlet while the threaded connection is outlet.

I'd still like to see how the rubber inlet line is routed around the steering column (from the hard line on the frame to the inlet barb).

 

[RonD]

Yes, there is no such thing as having one too many grounds

And if conditions are right air movement over the body parts WILL build up a static charge, which is why you might get a shock when putting key in or touch body metal, similar to what happens in your house
People often hang a ground strap from frame that drags on the ground when stopped to prevent this