New to me... Nightmare?

Good morning all!
I used to drive over the road when I was a kid but no longer do that. BUT, I just acquired a 1999 FLD120 single axle with a standard sleeper on it. It is a million mile truck and nothing spectacular or worth writing home about BUT it is mine all mine. haha

The previous owner actually delivered the truck to my driveway from 150 miles away so I know she runs and drives. The PO also said he thought one set of batteries might be bad because it didn't seem like there was enough "juice" to start it and it always needed to be jumped

Well, It's been here for a week now and I went out yesterday to see what he was talking about. I hop in and try to start it. The PO was right. very slow cranking and acted like it needed a jump. So I hop out and I smell hot electrical!!!

I go back to the batteries and find the ground post glowing red and smoldering! At least I'm smart enough that I didn't need a warning label telling me not to touch it so I left it a lone for a while as I take a look around.

So, I'm thinking to myself this slow crank could be one of 3 things...
1. Dead batteries. Seeing the post was glowing, thinking that is possible but probably not the main root cause.
2. Bad ground
3. Bad starter

I get to investigating and the glowing post comes to mind. Now. unlike every vehicle I have ever worked on, this one does not have a ground cable going from the batteries to the engine (or starter on this Cummins). The only ground the truck has is a small wire (maybe 1 AWG or 1/0 gauge) from the battery to the frame ground. That's it, nothing else grounding the batteries! Then at the starter, there is a 4/0 cable going from the frame to the starter negative.

Surely it wasn't designed like this, was it??? I'm no engineer but even I know grounds are a notorious fault on most things and this set up just has too many variables to fail to be correct.

So.... I went digging around in my piles of stuff and I found a length of 250 mcm cable. Ordered up a few lugs and will be installing the cable today. This SHOULD fix my glowing ground lug problem.

I'm just hoping the starter isn't burnt up from low voltage too many times...

There is also a couple of lugs that are cracked which need replacing. I'll do those also while I am there.

This girl is a complete truck and almost ready to work.
I'll be using her to move houseboats and avoid motel costs on long drives.

Any info on this truck would be awesome! Wiring schematics, common issues/problems to watch for, repair manuals, etc...

Also, I have a 1969 Ford N-750 for sale. This FLD120 is replacing it.

 

Thanks for the replies guys!!!

That just seems silly to me to run it thru the frame. Just too many variables to allow it to fail on such a critical electrical circuit.
But who ever said these engineers were smart? haha
The starter will draw what ever is available and will melt itself down internally if you allow it to. But, undervoltage will also burn up the brushes/armature also. I'm hoping this isn't the case this time.... Don't want to spend $400 on a new starter right now...

This one has a frame ground next to the batteries and then a frame ground next to the starter. No cables (except for positive) runs from the batteries to the starter or engine compartment. I know the frame ground is critical for the working cab systems but I just find it silly that a frame connection would be chosen by the manufacturer.

The rest is not directed to anyone. Just more info....
The frame ground makes sense in theory but I'm going to rid this system of the failure points and run the cable to the starter ground. It just makes sense to me to do it this way and get rid of a future headache. I'll be going thru this system pretty intensely. Ohming connections, replacing cracked lugs, adding the ground cable, cleaning the frame grounds, charging and testing the batteries, etc....

I'll post a picture of the old girl later!
Again.... Thanks for the r

 

Here she is....

 

It also creates more connection points which can/will corrode, work loose, crack, snap off, etc

Don't get me wrong, I'll still keep the frame grounds. I know those are critical for the design of the truck.
But honestly, you can never establish too many grounding points or routes in my opinion.

And, with the load that these starters take, grounding conductor size is just as critical grounding connections.
The battery to frame wire is undersized in my opinion as it is smaller than any other wire in the system. My guess is it is not stock and was replaced by someone that thought it would be enough.
This 250mcm cable is bigger than stock and I have enough to do the upgrade.
Thanks for the reply!

Not specifically directed to anyone....
Just a fun little fact..... DC voltage/amperage flows from negative to positive. The fuse box in every vehicle is actually designed to protect the power source (batteries) and not the system it's tied to. But that is the MSHA certified electrician coming out of me. lol

 

Remember, This is a million mile truck and there are going to be issues. Grounding is not one I want to have.

Better safe than sorry in my opinion. You can never have too many solid, clean grounds on a vehicle.

Keep in mind that a 00 cable has an ampacity rating of 195 amps where this 250mcm has an ampacity rating of 290 amps.
The grounding circuit is always as strong as it's weakest link. If these trucks only use 2/0 cable to connect to the frame, that has a limit of 195 amps under perfect conditions.

Upping the cable size for grounding can never be a bad thing.