MX5000 completely dead...need help

[msinc]

Thanks a million for all the replies fellas, it is greatly appreciated. Today I checked and verified ALL grounds, connections and cables. Every one of them, unless I missed something, is fine.
Looking at the wiring diagram {strange that it doesn't show a 40 amp main fuse, which I replaced anyway} I don't see anything that would stop this tractor from cranking over even if the OPC system is open. It appears that the OPC system disables the fuel solenoid so the tractor either: A. cuts off if it's running, or: B prevents the engine from starting for lack of fuel. It does not appear to have any means to prevent the tractor from cranking over.
Unless the wiring diagram is incorrect and failing to show other components like that fuse, I see nothing that can stop it from cranking over and dash indicator lights to light up if there is power to the ignition switch.......which brings me to a bad switch right out of the box!!!! I have not had time to test it yet, but first thing tomorrow I will. Thanks again for all the replies!!!!

 

[ki4dog]

If the symptoms changed when you changed the switch then I'd suspect the switch or anything you messed with changing it. Could have introduced a second problem.

 

[Mark_BX25D]

If the symptoms changed when you changed the switch then I'd suspect the switch or anything you messed with changing it. Could have introduced a second problem.

Yep. Coincidence happens, and it can do a number on your troubleshooting when it does!

Never assume coincidence, and never rule it out.

 

[msinc]

I am happy to report that the end of the big mystery is here!!!! While double checking the ignition switch I noticed when I was moving it around the dash indicator lights blinked momentarily. It was in the run position and I was lucky enough to see an arc at back of the wiring harness connector. When I turned it over to have a better look the main power wire fell out. The female spade connector for this wire must have either been crimped too tight and it eventually broke away or it was not crimped tight enough and arced itself to death. We'll never know, I did remove all the other terminals and have a look. All of those had good terminals and nice snug crimps with no corrosion.
For the record, and many of you guys may know this, but since I never had trouble with the OPC system I sure did not. The engine will crank over, the dash indicators all light and the glow plugs will energize if you choose, but the engine will not start. It will crank until the battery dies, you stop or you fix the problem. Careful wording in the manual..."engine wont start" not engine wont crank.
This was a very confusing problem for quite some time. Initially, I had gotten some bad fuel and had water in it. It would eventually cut the tractor off and I had to remove and drain the separator. What made it worse is that it would not stall for a day or so every time I emptied the separator.
I unplugged the connector on the ignition switch and check for voltage numerous times and the probe on my VOM pushed the bad terminal back far enough to make contact and read the full 13.1 volts, but plug it back in and it had no connection. Had I missed that little spark I would still be out there chasing this problem. Thanks again for all the replies fellas!!!!!!

 

[D2Cat]

Good that you discovered the open connection. I would think that would be discovered when the switch was replaced.

 

[SidecarFlip]

I must say I have little to no faith in mechanical crimps and I always solder the connections anyway.

 

[Mark_BX25D]

Mechanical crimps are used in aerospace, are mil-spec in places where solder is prohibited due to reliable concerns, and are "preferred" over soldering for marine applications.

Just like soldering, if it's done wrong, it will cause problems. But it's a lot easier to learn to crimp correctly than to learn to solder correctly.

Use the correct tools (not pliers), use decent connectors (not the vinyl garbage from your local WalMart or Autozone), line up the seam properly, and you'll get more reliable connections from crimping than from soldering.

 

[msinc]

Good that you discovered the open connection. I would think that would be discovered when the switch was replaced.

Yes sir!!! This particular switch comes with its own attached wiring harness that's about 6 or 7 inches long with a "molex" like quick connector. Strange that the wire never fell out when I changed the switch, then again the wires are all taped together right up to the connector so it kind of couldn't really just fall out even though there was nothing to hold itself in. The other wires did the holding being taped to it.
I had just plugged it in and unplugged it several times when just by luck I left the switch on the run position and saw the wire arcing. Had it not been for seeing the spark I would probably still be trying to figure this thing out.

 

[msinc]

I must say I have little to no faith in mechanical crimps and I always solder the connections anyway.

I just so happened to have the correct female spade to do this, but prior to finding it I was seriously considering taking all four wires and soldering them together, and doing away with the connector. I mean 6 inches away the wires all lug to the back of the switch, so it's not like you really need this connector. It just makes it easy to swap out the switch. One would hope having to change out ignition switches wouldn't need to be done so often that it needs to be made slap simple!! I think now looking back I would be more comfortable with soldered wires and shrink wrap. That also would have made a better repair because it would have kept dirt/moisture out of the connection. One thing I did was spray the connector down with terminal protectant and gave it two layers of black tape.

 

[msinc]

Mechanical crimps are used in aerospace, are mil-spec in places where solder is prohibited due to reliable concerns, and are "preferred" over soldering for marine applications.

Just like soldering, if it's done wrong, it will cause problems. But it's a lot easier to learn to crimp correctly than to learn to solder correctly.

Use the correct tools (not pliers), use decent connectors (not the vinyl garbage from your local WalMart or Autozone), line up the seam properly, and you'll get more reliable connections from crimping than from soldering.

Once upon a time I was J-Std-2000 certified and I still have my crimpers. I agree that there's a little more to soldering correctly and that using the crimpers are easier to get a good connection. I do like the ability to be able to seal up the connection and lock out moisture and contaminants though with solder and a fixed permanent connection. I think using quick connectors in this location might not be the best way to do it. Might have been better if they were sealed so-called "weatherpac" connectors instead of just open backed molex type.

 

[SidecarFlip]

Way too complex for me. This ain't 'aerospace', it's a tractor (or automotive) applications. I always tin the ends of my connections and then solder them to the connectors and finally heat shrink the over wrap.

All my 'Molex' connectors get di-electric grease inside too.

 

[SidecarFlip]

gave it two layers of black tape.

I never use tape, always heat shrink tubing. Tape gets sticky and unravels.

 

[NHSleddog]

Way too complex for me. This ain't 'aerospace', it's a tractor (or automotive) applications. I always tin the ends of my connections and then solder them to the connectors and finally heat shrink the over wrap.

All my 'Molex' connectors get di-electric grease inside too.

Flip, Aerospace tends to build at a much higher quality than earth based tractors. Crimps are simply better than a soldered assembly (ESPECIALLY in a TRACTOR that is KNOWN for VIBRATION).

We do a lot of chassis and PLC work and it all calls for crimping, not soldering. Most of these PLC's are in industrial environments doing industrial work.

It is OK for you to do something wrong, but you shouldn't encourage others to do the same thing wrong.

 

[Adam G]

Glad your mystery is resolve

 

[BigG]

Flip, Aerospace tends to build at a much higher quality than earth based tractors. Crimps are simply better than a soldered assembly (ESPECIALLY in a TRACTOR that is KNOWN for VIBRATION).

We do a lot of chassis and PLC work and it all calls for crimping, not soldering. Most of these PLC's are in industrial environments doing industrial work.

It is OK for you to do something wrong, but you shouldn't encourage others to do the same thing wrong.

Why or how is soldering wrong? It seams to me that it is two different ways to get to the same destination. I have seen crimped battery cables corrode and fail. I have never seen a soldered cable fail at the connection.

How much does the cost of production go into the method of the connection? Soldering would seam to be more costly due to the labor involved.

 

[msinc]

Glad your mystery is resolve

Thank you sir, I am too....been out of the mechanical field for too long and it only took me several days to stumble upon the problem. The only good thing for me is that I wasn't the only one stumped, so I don't feel too bad. M

 

[NHSleddog]

Why or how is soldering wrong? It seams to me that it is two different ways to get to the same destination. I have seen crimped battery cables corrode and fail. I have never seen a soldered cable fail at the connection.

How much does the cost of production go into the method of the connection? Soldering would seam to be more costly due to the labor involved.

It is mainly for applications involving vibration.

Soldering creates a weak point where the solder meets the wire. Soldering is best for low resistance, but crimping is best for vibration. Also, soldering with flux always leaves some residual acid on the assembly inviting corrosion. NASA could explain it better than me.

I am not saying doing something one way won't work, but one way in this application will work better.

We used to see solder/tinning specified all the time for screw terminal blocks. You don't see that anymore, now they specify specific crimp caps to use on the screw terminals. This is due to corrosion/breakage/failure.

 

[BigG]

It is mainly for applications involving vibration.

Soldering creates a weak point where the solder meets the wire. Soldering is best for low resistance, but crimping is best for vibration. Soldering with flux always leaves some residual acid on the assembly inviting corrosion. NASA could explain it better than me.

I am not saying doing something one way won't work, but one way in this application will work better.

We used to see solder/tinning specified all the time for screw terminal blocks. You don't see that anymore, now they specify specific crimp caps to use on the screw terminals. This is due to corrosion/breakage/failure.

Ok that makes sense. Thanks.