Negative starter cable not connected?

lily · June 05, 2010, 11:39:42 AM

Hi everyone,

I have a 1995 International shortie school bus with a T444E engine. I was looking at the cabling in the battery box and there are two giant black leads and one red one coming into the box, but only one black lead is hooked up. The black lead that is attached goes right to the bus frame. The lead that is not goes to the starter, as does the red lead (which is attached to the battery +, of course).

I understand why this works; somehow the engine block that the starter is bolted to is grounded to the frame, probably via another fat ground lead. My question is, shouldn't that lead be hooked up anyway? Is there some reason it wouldn't be? This unattached lead also has a couple smaller wires that run with it, and Im not sure what they go to, but I am sure they are grounded the same way the starter is.

Thanks for your help!
Lily

Just Dallas · June 05, 2010, 11:46:47 AM

Removed

lily · June 05, 2010, 11:55:48 AM

Quote from: Now Just Dallas on June 05, 2010, 11:46:47 AM
Give us a few more hints.
I don't think IH ever made an IH Skoolie, but was probably built by one of the major School bus builders, like Ward, Bluebird, Thomas, etc.
Some of us have manuals for those buses, and each one is different.

Oh! I didn't realize it would vary by coach type. It is a Carpenter, 29 passenger no handicap. It looks like this:

You can see what I am talking about here:

Three leads come in the back, red one goes to the +, one black one goes to the - (and the frame), and the other is just hanging out there, but runs to the starter.

The bus starts fine though.

Lily

luvrbus · June 05, 2010, 12:06:07 PM

Dallas, they do build school buses in Tulsa at the old Boeing Plant along with their new 40' and 45' intercity coaches which are not bad looking fwiw.

good luck

Lin · June 05, 2010, 12:06:22 PM

Is the unconnected cable actually connected to the starter or does it just terminate there without being connected to anything? If it is not connected at either end, it was probably a hot cable to something that may not be there anymore. Merely being black does not mean that it was a ground cable. It may even have been an old, faulty positive cable that was replaced by the red one and abandoned. People do all sorts of things.

lily · June 05, 2010, 12:21:59 PM

Quote from: Lin on June 05, 2010, 12:06:22 PM
Is the unconnected cable actually connected to the starter or does it just terminate there without being connected to anything? If it is not connected at either end, it was probably a hot cable to something that may not be there anymore. Merely being black does not mean that it was a ground cable. It may even have been an old, faulty positive cable that was replaced by the red one and abandoned. People do all sorts of things.

Here is a picture of the starter from the front:

The large cable in the foreground on the starter body is the black lead that is not connected in the battery box.
The red lead is attached to the solenoid farther up, it has that black cable wrap on it.

Hope that helps!

Lily

Gary '79 5C · June 05, 2010, 01:03:19 PM

Could the orignal equipment have called for Two (2) batteries, but only one is within the batt comp currently ??

Not sure of the size and if the comp could accomodate a second batt, Just a thought.

Very Nice shortie, schoolie.

lily · June 05, 2010, 01:09:43 PM

Quote from: Gary '79 5C on June 05, 2010, 01:03:19 PM
Could the orignal equipment have called for Two (2) batteries, but only one is within the batt comp currently ??

Not sure of the size and if the comp could accomodate a second batt, Just a thought.

Very Nice shortie, schoolie.

It currently has two batteries, and room for a third. Maybe it came with three to start with? I am putting my house battery in there, which is why I am looking at all of this. I did wonder if I really needed two starting batteries, but I have never owned a diesel bus so I don't know!

Thanks

Lily

Iceni John · June 05, 2010, 01:17:40 PM

Most school buses came with two batteries, often Group 31 or 8D. Even though your engine probably starts just fine with just one battery, it's nice to have the cranking capacity of two batteries for cold weather, or if one battery is getting old and tired (they should however be replaced together), or if your engine needs lots of cranking, or helping jump-start someone else's bus. My bus will start with just one Group 31 (less than 1,000 CCA), but I have two 8Ds (2,500 CCA total) just in case. Remember, as your starting volts decrease, the current increases, and then you risk burning out the starter, or worse.

John, happy to see some more yellow here!

Runcutter · June 05, 2010, 03:22:34 PM

Lily, if you just bought a recently retired bus, how about calling the Superintendent of Maintenance of the system that ran it. He/she can probably tell you right out what's going on. Or, with a photo (or diagram) of how both batteries are hooked up, (series or parallel), that may reveal something.

Although I'm strictly a 12-volt guy, could the funny wiring have something to do with series/parallel? -- In other words, is it a 12-volt or 24 volt system?

Your profile shows that you're in Texas. A lot of us are scattered throughout the state. If you're semi-permanently in one place, posting your location (see my signature line) might reveal that one or us is nearby.

Arthur

lily · June 05, 2010, 04:44:34 PM

Thank you John

Arthur, this bus went through a couple pairs of hands before it came to mine, so there is no telling what the thinking was (or not!) of whoever left it off. It is definitely a 12V system though.

I am in DFW, near the airport, so you arent too far from me!

Lily