BMY M931A2 - assistance Please - No Power after Starter Replacement

[MOS91E]

I have a 91 BMY M931A2 Tractor that the starter went out on.

I am smacking my head here trying to figure this out... im sure its something so simple that im going to say duhhh but right now I need some advice from you guys because im at a loss here.

I replaced the starter with a new Re-manufactured starter, known to be good. I reconnected everything the same way I took it off and when I go to fire up the truck I have no power to any of my gauges or even the blower. I took out the volt meter started my diagnostics found out im not getting a good ground.

Temporarily ran a jumper cable directly from the battery to the frame and bingo I have power to my gauges but still no start. I disconnected PCB and jumped the terminals to eliminate pcb as the problem.
Jumped the starter and bingo truck fires right up. Ok so now im back on the road moving again as long as I dont turn the truck off im good right.

Next day I attempt to actually fix the problem correctly so I can start the truck normally and now I have no start even when I follow the temp process above.

To get any power whatsoever I need to run a jumper cable from the (-) (+) bridge on the batteries to the frame which to me indicates I have a bad ground somewhere but where i have no idea. Im thinking the starter ground may be reversed or something since it went back together exactly as I took it off which previously worked with original starter.

But even when I jump the starter (+) main feed to (+) solenoid bendex will not engage to start truck like it did the day before.

Has anyone here experienced anything like this before or heard of something like this?
Any suggestions because i honestly cant figure out what the heck is going on?

Like i said im sure its something so simple that im having a brain dead moment here!
Thank you in advance and Yes I have scoured the TM's for the truck and still am at a loss!

 

[adamsoffroadperformance]

by chance there's too much paint on the starter where it meets the block and bolt heads and isn't making good contact? just a random thought

 

[MtnSnow]

Absolutely double check your wiring in the battery box (there should be a wiring diagram on the underside of the seat/lid) and double check the wire numbers at the starter to make sure the right wires are going to the right places as several are pretty easy to get mixed up. (this was one of the issues with my M925a2 and why I was able to purchase it so cheaply since the seller couldn't get it to start/run (along with fuel/air leaks)

 

[74M35A2]

You likely left a large "-" cable off somewhere. Back of the starter, block, frame, battery bank, or other. Look from underneath, you can usually find it hanging down. HD starters are grounded directly as to not pull 1-2 thousand amps through the engine block bearings. I have never checked the schematic, but usually the battery bank ground cable will route to the back of the starter first, and then the rest of a truck pulls ground from that point, to the engine block, frame, etc....

 

[Doug Roberts]

I just think you need a new PCB

 

[Andyrv6av8r]

I just think you need a new PCB

Or replace the 2 relays in yours.