'99 763 won't turn over... trying to help a friend...

[couchsachraga]

Greetings! I'm trying to help a friend of mine out and get his 763 up and running again - I've done a bit of internet searching and found that others have had this problem... but not posted up what it took to fix it. Any help would be GREATLY appreciated as we have a Jan. thaw right now and he'd like to get back to moving snow before it all freezes sold Tuesday.... Machine was starting and running great (about 900 hours on it since new, he bought in fall), he let it sit for a week (and it was very cold, -20 F or so, we're in the 40's for highs now). Turn the key to on, tosses two codes which don't make sense (8-21 and 2-16, hydraulic constriction and overheating?). Turn key to to start (after glow plugs warm), fuel solenoid will click over, that's it. Testing where power is, power to + terminal nut on starter. Shorting that out to S terminal (from key) unit does not turn over when in machine. Take it out and bench it and it will kick out and turn. Adding a second battery will make it kick out and turn slowly. Also confused over when is in "run" position - main + terminal on starter (wire right from battery) will read 0, or 6v, then something clicks (glow plugs?) and voltage rises back up. Voltage in battery seems fine, each cell tests fine. Power on small wire in back (non S wire) is odd - when key is on (or turning over?) shows NEGATIVE voltage (-12.x, about what the battery is). Thanks for any help!

 

[OldMachinist]

First I'd have the battery load tested, sounds like its bad.

 

[couchsachraga]

First I'd have the battery load tested, sounds like its bad.

Battery is 2 months old, Interestate special order. But yes, I was kicking myself for not having my battery tester with me. He did pull it, clean the terminals and cables (and test them for resistance, they check out fine), and check each cell for specific gravity - by that it looks like a good battery. Unless it is the switch or something else odd, I'm guessing the starter - when you add a battery and short the main + terminal (starter) to the S terminal it barely turns over (kicks out, doesn't even do a full rotation). I wish I knew if it would kick odd codes out if there was something going on in the starter.

 

[[email protected]]

Battery is 2 months old, Interestate special order. But yes, I was kicking myself for not having my battery tester with me. He did pull it, clean the terminals and cables (and test them for resistance, they check out fine), and check each cell for specific gravity - by that it looks like a good battery. Unless it is the switch or something else odd, I'm guessing the starter - when you add a battery and short the main + terminal (starter) to the S terminal it barely turns over (kicks out, doesn't even do a full rotation). I wish I knew if it would kick odd codes out if there was something going on in the starter.

if a battery dies and then freezes, it ruins the battery. i'm guessing something drained the battery and that extreme cold killed it.

 

[couchsachraga]

if a battery dies and then freezes, it ruins the battery. i'm guessing something drained the battery and that extreme cold killed it.

Could be. Light come on fine, and battery voltage is 12.54 v though, so other than doing a load test it looks OK. Again, wish I'd had my battery tester with me! He has a local diesel and equipment mechanic coming over tomorrow afternoon to try and see what's up. I'm sure he'll be trying all morning to get it running though.

 

[Tazza]

Could be. Light come on fine, and battery voltage is 12.54 v though, so other than doing a load test it looks OK. Again, wish I'd had my battery tester with me! He has a local diesel and equipment mechanic coming over tomorrow afternoon to try and see what's up. I'm sure he'll be trying all morning to get it running though.

The poor mans way to test a battery is to jump the starter. Jump from +ve to the pin on the starter solenoid, see if it cranks. If it just clicks, you have a bad battery or connection.
The starter does pretty well for a load. Even get a helper to turn the key while you hold the meter on the battery, see if it drops to zero.

 

[[email protected]]

The poor mans way to test a battery is to jump the starter. Jump from +ve to the pin on the starter solenoid, see if it cranks. If it just clicks, you have a bad battery or connection.
The starter does pretty well for a load. Even get a helper to turn the key while you hold the meter on the battery, see if it drops to zero.

the alternator could be bad too, bad alternator can ruin a battery as well

 

[couchsachraga]

the alternator could be bad too, bad alternator can ruin a battery as well

Understood... and tried. As noted in top post jumping that main starter terminal to the S (start / solenoid) produces.. nothing! Not even a click. Adding a second battery to it and the starter will kick out and turn slowly in the machine, certainly not enough to crank over. Take the starter out and hook it up, kicks out and spins. I don't have enough experience with Bobcat starters to know how fast it should spin, or with how much torque. It certainly doesn't jump as much as I've seen others do, nor spin as fast, but again, I have no baseline of what to expect. Keep the thoughts coming! Thanks!

 

[Bobcatdan]

Understood... and tried. As noted in top post jumping that main starter terminal to the S (start / solenoid) produces.. nothing! Not even a click. Adding a second battery to it and the starter will kick out and turn slowly in the machine, certainly not enough to crank over. Take the starter out and hook it up, kicks out and spins. I don't have enough experience with Bobcat starters to know how fast it should spin, or with how much torque. It certainly doesn't jump as much as I've seen others do, nor spin as fast, but again, I have no baseline of what to expect. Keep the thoughts coming! Thanks!

I'm thinking you have bad battery cables. Just had a 853 that I couldn't jump. Besides the solenoid looking like it was bad, I could see the cables were junk. Pulled the starter off and benched tested, it would spin over when the solenoid wanted to work. Took it to a starter/alt shop just to have it verifed bad be on the solenoid and it was junk. They could see signs of bad grounding. Take the starter to be tested and go from there.

 

[couchsachraga]

I'm thinking you have bad battery cables. Just had a 853 that I couldn't jump. Besides the solenoid looking like it was bad, I could see the cables were junk. Pulled the starter off and benched tested, it would spin over when the solenoid wanted to work. Took it to a starter/alt shop just to have it verifed bad be on the solenoid and it was junk. They could see signs of bad grounding. Take the starter to be tested and go from there.

Cable resistance (or is impedance the word?) tested out fine. I should mention the battery that it turned over and spun out with was a different battery (same one we used to add more juice). The starter didn't "jump" as I'm used to them doing though - but perhaps that is normal for a bobcat starter. Might get tested at the bobcat dealer tomorrow, we'll see. I'm still confused over why it is throwing those other codes though.

 

[OldMachinist]

Cable resistance (or is impedance the word?) tested out fine. I should mention the battery that it turned over and spun out with was a different battery (same one we used to add more juice). The starter didn't "jump" as I'm used to them doing though - but perhaps that is normal for a bobcat starter. Might get tested at the bobcat dealer tomorrow, we'll see. I'm still confused over why it is throwing those other codes though.

Low voltage will make them throw all kinds of different codes. It confuses their little brain. Until you get the starting problem fixed I wouldn't worry about the codes.

 

[couchsachraga]

Low voltage will make them throw all kinds of different codes. It confuses their little brain. Until you get the starting problem fixed I wouldn't worry about the codes.

Ah, but it turns out that was the key - even though at low current the negative cable tested OK, running a jumper cable from the neg. battery terminal to the block and it started right up, not codes or anything. Terminals on each end had been cleaned etc..., so the problem lies in that neg. battery cable. It stumped the the mechanic for a bit, then he started working through it methodically, and in retrospect it all made sense. Thanks for all the thoughts - hopefully this thread will help someone else in the future! Don't just test those battery cables - use a jumper cable to bypass them and be sure!