TC33 Starter Problem

[MTGreen]

Well it seems like there's only a couple things it can be at this point. Since the starter is new and your positive battery cable is new and you ruled out the possibility that your battery is putting out good voltage but no amperage: either the ground circuit to the battery negative is inadequate or the starter solenoid and motor are not actuating together because they're disconnected electrically or inappropriately shorting. I think the inadequate ground scenario is more likely. You said you connected a wire from the plate that the starter is mounted to to a wiring harness ground on the block. What about the block to negative terminal connection along with the chassis to negative terminal connection?
Excessive resistance in your ground circuit causes a voltage drop per ohm's law. It doesn't take much power to free spin the starter so it is conceivable that inadequate grounds could spin the starter without actuating the solenoid.
The other thing I would try is not jumping the terminals to try to start it and use the ignition switch instead. There's some variation on starter wiring setups and there also can be some variation on interpretation of what jumping terminals means to folks. This can eliminate additional variables

 

[Noytheyah]

Well it seems like there's only a couple things it can be at this point. Since the starter is new and your positive battery cable is new and you ruled out the possibility that your battery is putting out good voltage but no amperage: either the ground circuit to the battery negative is inadequate or the starter solenoid and motor are not actuating together because they're disconnected electrically or inappropriately shorting. I think the inadequate ground scenario is more likely. You said you connected a wire from the plate that the starter is mounted to to a wiring harness ground on the block. What about the block to negative terminal connection along with the chassis to negative terminal connection?
Excessive resistance in your ground circuit causes a voltage drop per ohm's law. It doesn't take much power to free spin the starter so it is conceivable that inadequate grounds could spin the starter without actuating the solenoid.
The other thing I would try is not jumping the terminals to try to start it and use the ignition switch instead. There's some variation on starter wiring setups and there also can be some variation on interpretation of what jumping terminals means to folks. This can eliminate additional variables

After I changed out the + wire I figured it was a ground issue. At first, I forgot to disconnect the ground from the battery and connected a jumper cable from the battery to the starter mounting bolt, with same results, however, I started blowing the 30amp main fuse. I disconnected the the battery ground cable and left the jumper cable connected with the same results including blowing the fuse. I replaced the - cable with a new one removed the jumper with the same results. When I engage the starter for (guessing 10 seconds or so) it will eventually blow the 30amp. With the jumper cable attached I get .6-1v drop, which to my understanding is pretty significant.

The ground from the battery is bolted to the front frame below the engine. The engine is bolted to the frame and the panel the starter bolts to is bolted to the engine. I never removed or messed with anything in this path. The only electrical work I did was change out the old relays/relay harnesses. When changed them out I triple checked each wire but I plan to check them again today. One relay is the safety start which I know is working, the other is the start circuit relay and I believe the last is the lighting circuit. Incidentally, the lights on the rear work but the headlights have no power. I was planning to troubleshoot that issue once I had the tractor put together. Obviously the start circuit is working but seems something is sucking the juice from the starter that I’m missing. I get barely .1 voltage drop when the lights are turned on.

 

[MTGreen]

So you have a short in the system or you wouldn't be blowing fuses. Also visualizing that you have a wire going from the battery to the frame and doing a voltage drop test does not guarantee that you have a good ground as that can change at high amperage. You should remove that wire, scrub the contact points with a wire brush, and look carefully at where the wire is crimped to the ring terminal. You can also diagnose whether ground is an issue by running a wire from the starter mounting bolt directly to the negative battery terminal -if that fixes the problem you know it's a ground issue. Do you have a wiring diagram you can post?

 

[ruffdog]

NH TC33DA Wiring Schematic.

 

[thclimer]

Wow, you are blowing the main 30 amp fuse, definitely something is grounding in that circuit.

Does the fuse blow when you turn your key to the first position for the glow plugs? If not then its probably not the glow plug relay, I'd then look at the PTO safety start relay or the Safety start relay.

 

[Noytheyah]

So you have a short in the system or you wouldn't be blowing fuses. Also visualizing that you have a wire going from the battery to the frame and doing a voltage drop test does not guarantee that you have a good ground as that can change at high amperage. You should remove that wire, scrub the contact points with a wire brush, and look carefully at where the wire is crimped to the ring terminal. You can also diagnose whether ground is an issue by running a wire from the starter mounting bolt directly to the negative battery terminal -if that fixes the problem you know it's a ground issue. Do you have a wiring diagram you can post?

With regard to the battery cables. Last year I replaced both because the tractor would only activate the solenoid. I thought it was a dead battery but I changed the cables first which ended up being the issue. The tractor has custom battery cables ($150) that plug into the harness the previous owner had replaced the OEM cable and hacked into the harness, he just replaced the factory fittings. The cables I replaced with are standard Orielly auto cables with the large holes and the bolt having to make contact with the center of the lug hole. At first I thought this was an issue so I bought some solder lugs and soldered them on the cables. That didn’t cure my problem so I replaced them with crimp on. Didn’t solve the issue so I soldered the crimp on still no change.

I did run a jumper cable like you mentioned from bat - to the starter mounting bolt. That’s when I started blowing fuses, which really doesn’t make any sense to me. At first I forgot to disconnect the battery ground so it was grounded with the jumper cable and with the battery ground. When I realized this I unhooked the battery ground.

 

[Noytheyah]

Wow, you are blowing the main 30 amp fuse, definitely something is grounding in that circuit.

Does the fuse blow when you turn your key to the first position for the glow plugs? If not then its probably not the glow plug relay, I'd then look at the PTO safety start relay or the Safety start relay.

No the fuse only blew when I had the jumper cable connected from the - batt to the starter mounting bolt AND I would run the starter for several seconds (10 sec +/-). I was running the starter for a longer time to check the voltage. As the voltage would drop (up to 1v) that’s when the fuse would go. Still I don’t understand how grounding the battery to the starter mount would cause a short.

 

[MTGreen]

There's something going on in your wiring harness that's causing the problem. I would bypass the harness all together by running a single heavy wire from your battery positive to the starter and then applying power to the starter trigger. The starter should turn the engine appropriately at that point, then you can start working through your wiring harness and figure out where you are shorting out. You may want to consider unwrapping a good portion of the harness and looking for shorts and cracks etc

 

[LittleBill21]

Voltage drop tests only work during high current such as the starter actually turning. based on the amount of work done, and the fuses blowing. I would disconnect literally everything in the start circuit and run direct wires to a battery, and work your way back

 

[Noytheyah]

There's something going on in your wiring harness that's causing the problem. I would bypass the harness all together by running a single heavy wire from your battery positive to the starter and then applying power to the starter trigger. The starter should turn the engine appropriately at that point, then you can start working through your wiring harness and figure out where you are shorting out. You may want to consider unwrapping a good portion of the harness and looking for shorts and cracks etc

I’ve done that already. I didn’t use a switch but I connected the bat + to the starter like it should be and the - from battery to the starter mounting bolt. I used a separate wire clipped to the + battery terminal and touched the other end to the starter solenoid where the switch would connect. The starter still turns slow and bendix doesn’t advance. I even put a piece of tape over the starter gear to verify it was or wasn’t advancing. Then I removed the starter and set it on the tractor tire still hooked up the same way and it functions normally. So no matter if its in the tractors wiring circuit or not, the bendix will not advance if it’s bolted to the tractor. I’ve even loosened one of the bolts to make sure I wasn’t binding it somehow, same result. That’s why I’m so confused. No matter how it’s wired, if it’s physically attached to the tractor it won’t work properly. Off the tractor they both work fine