Hey guys; did not find solution in the prior recent post Komatsu WB140-2N wont turn over- Discussion in ' Tractor/Loader/Backhoes ' started by Shblack , Jul 31, 2022 . so starting fresh with this post...even though the Backhoe will not Older & has some worn buttons/switches remaining unidentified Had been running and starting consistently; then one day after getting out of the woods, parking in normal location, and cleaning greenbriar and branches from below driveshaft & other; It did not want to start, Checked battery -new as of 12/21 -I noticed the starter was really beat up; so I replaced the starter- Battery and @ starter I am getting 12.7-12.8v; seems to have good continuity @ all grounds checked all (discovered) related fuses; confirmed operable or replaced. have tried jumping @ battery, key and direct -screwdriver & jump cables-@ starter to bypass possible breach/loss starter has been confirmed operational; flywheel & engine move w socket-not locked up... pre ignition shows fuel, power, turn to start then just the tapping starter, or nothing at all SO ---- I suspect it must be electrical; no not a genius to figure that out Discovered some rodent damage @ wires behind console. repaired what I could find; some relays were found- but don't know how to test a relay ?? to determine if it needs replaced . Not sure how to test continuity from in the cab to fuse box under hood- maybe extensions on the test leads ?? w aligator clips ?? This is on a farm/ranch, so just me ever using it; is there a work around wiring to bypass a relay and test that way ? Certainly the most beautiful fuse box; the 'empty' has been replaced 2 a new 80 This button labeled 'power' but never seemed to do anything previously
Please post machine serial number, electrical schematics can change by serial number. Does the engine turn over with the starter?
No sir, not turning over; just tapping of the starter in and out...that is why I think maybe there is a relay or something that should be happening but is not...I'm not the dumbest guy, but I am not mechanic-smart like some folks...sure wish I was... Thinking I will check the battery cells just to say I did everything I know...
here is the elec specs if it helps...Still have not discovered the source of the non-start
So when you turn the key to start, the starter "taps in and out"? That tells me you have power going where it's supposed to but not staying there under load. So you have to do the same checks you're doing under load, which is going to be difficult, so you will probably be bypassing relays, switches etc. to test. No easy way to explain electrical troubleshooting, but I like to start at the battery, then the starter, just like you've done, but now read the voltage when trying to start. A half hour on youtube general vehicle electrical diagnostics, and a power probe should get you pretty far toward finding the issue.
Any chance it's the wrong starter? Teeth are hitting and bouncing back? Joe H
Sounds like a safety relay/starter relay issue. You really need a wiring diagram to help troubleshoot it. Dig into the archives. There are good threads on the subject.
You said in your first post that you bypassed everything and hooked the starter directly to the battery with jumper cables? Did the starter work then and turn the engine over? Can you put a picture of the starter up?
if you have a battery load tester hook it to the starter and see if you get a power drop. If starter is clicking then the electrical system is doing what it is supposed to sounds like a bad connection that looses power under a load
Have the wire schematics; -posted pdf above
Starter works, but engine not turning; starter seems to be popping in and out...enginge & flywheel confirmed as 'not locked up' Starter appears to be same size; confirmed it is same #teeth; I have measured the depth to flywheel and starter gears pop out that far (when it is tested freehand) and measured the extension distance
Starter does the same even with straight to starter power...makes me think there is some odd safety relay or ?? that is preventing other functions...may look into trying to test the alternator....not sure how to test relays- yTube perhaps
Do not have a Load tester; might test the battery fluids and run it to AutoZone or Napa for a load test
Now I still get 12.7 @ my battery and starter; but no power w @ the key & console.... Could that be rat chewed wire somewhere or perhaps a failed relay ? Any advice how to test a relay (or hardwire bypass) ? Any good resources to purchase the relays Have already tested and replaced all failed fuses
Spell it out for us. You said the starter works, and now you say the starter doesn't turn the engine over??? That's kind of what a starter should do in my book. IF you short the two big terminals on the starter solenoid, what happens? If you short the big battery terminal on the starter solenoid to the little terminal on the starter solenoid, what happens?
What kind of starter, post a picture of it. If you could record a video with sound it might be helpful. I think I've seen this trick eons ago, starter solenoid wasn't moving the bendix far enough & it would just bang back and forth. Joe H
Was there a spacer that maybe you left on the old starter
Apology for the confusion.; hope this clarifies current experience. Perhaps I should have typed The starter is 'operable but not performing intended function'; when out of the backhoe and tested, bendix pops out and spins. I have measured with calipers the extension and the distance from mount position to the flywheel; these measures are compatible. When in the machine it just sounds to pop in and out (tapping) and does not turn the engine/flywheel. Same condition when shorted across pwr to start or ground terminals. Lately, I am getting no power at the key/console- though I still have power at the battery, starter, etc. I am looking into testing relays; how to test alternator; and tracking down possible breaches in the electrical system.
A few times early on with the start sequence I was getting a bit of smoke from the battery area...could not see specifically where from the cab...I suspect that is not a good thing
When in the machine it just sounds to pop in and out (tapping) and does not turn the engine/flywheel. Is this tapping rapid, like machine gun ? How fast, and how long will it do it if you leave power applied? Bendix is hitting the flywheel and bouncing back and forth? Joe H
To me, this is a separate issue from the no power to the key, though they may trace back to the same bad connection or something similar. When you short the terminals on the starter solenoid, you're eliminating all of the ignition switch circuit. That has narrowed the problem down to the battery, to the cables, to the starter, to the flywheel. Something in there is not working. If your old starter started doing this, and the new starter is doing the same thing, my first suspect is a bad battery cable somewhere, I'd get a simple light bulb voltage tester and test your battery cables for voltage drop under load. I say a light bulb because it's easier than the functions on a multi meter that would catch that fast voltage fluctuation. So a probe type with the probe stuck in the negative battery TERMINAL, and the clip on the starter body, and see if it lights up or flickers when you make the starter do that rat a tat tat. Then move to the positive battery terminal to the big terminal on the solenoid.
Just like the first part of the vid above....rapid
You vid wasn't up when I asked. I think the teeth aren't going into the flywheel. Slip an open end wrench over the shaft between bendix and end of starter and energize it, See if it does the same thing. Starter off again, sorry. Joe H
? As in remove the starter. What I picture occurring with this scenario is the bendix coming out spinning and throwing the oe wrench into my face ?
Wrench is over the shaft, bendix will hit it but bounce back. You are holding the wrench in place, it's not going anyplace. Yes remove starter, something ain't right. It's either the cables or the starter and you think you've eliminated the cables? Joe H
Confirmed; I am unsure about the cables; primarily because the new starter is doing the same as the old- & the old was starting the machine since I purchased it -backhoe- last yr. **Until a month + - ago after I was doing a lot of work in the woods, small trees, greenbriar, all smashing around beneath, had to cut & remove from driveshaft & wedged in various spots....which is why I suspect cables- though the portions of cables I can see and access appear to be consistent and not visually compromised....other than some of the smaller which I repaired from rat nest behind the console.
As I have no idea what your machine looks like I don't have any guesses about the cable problem if that's it. Were it me, I'd take the battery out and get a battery cable directly to the starter and a good ground close to it and see what happens when you've eliminated the factory cables. I know on mine I'd need about 12' of cable to leave the batteries where they are, that's why I'm suggesting moving the battery. Joe H
If you take your machine cables off the starter, pull another vehicle up near and use jumper cables off that vehicle, one clipped to ground, the other + just used to touch the stud on the starter, then what does it do? That eliminates all battery cables, relays, etc on the machine.
Touching the starter posts with jumper cables can produce spetacular sparks and damage. It would be better to connect the positive cable to the starter and the battery being jumped from, and then connecting the ground cable.
No news, must have fixed itself? Joe H
Dude, I wish.... bought a load tester & cell-specific gravity tester ystdy....2 of the 6 cells tested a bit low; the other 4 were well in the good range...Load test was in the okay range...All fuses operable... Still plan to try and figure out how to test alternator-without the machine running- may have to pull & take to AZone or OReilly for that... May have to pull cab panels or run wires direct to key, fusebox, etc ??....Nearing the point of utter sadness and despair.
since you got a load tester hook the tester up to the cables right at the starter th9s will tell you if you have bad cables or not
Good to know; I will try that
Load testing the condition of a battery should be done directly on the posts of it. Dirty or corroded cable connections can give false readings.
12.7v at battery no load; 11.8v w multimeter under load; 11.3v w multimeter under load at starter end of ~6'cable; slight breach/crimp discovered at power cable- bought new cable, may try that direct jump from the truck? 3500Ram, not sure if crank amps will be enough to test adequately ? Might break down and just buy another 4DLT battery- this one is under 1yr old-guess I'll see if TSC has warranty? Alternator & starter tested & confirmed good @ OReilly.
They are replacing the starter load with the battery load tester so they can check for bad cables or terminals. Bad Bob
I am aware of that. My comment was meant to indicate that I would do a load test off of the cables and then battery posts.
OPERABLE; thanks for all the tips & tricks. Ended up replacing the damaged power cable -7'- and correcting loose primary ground terminal; That seemed to be the primary issue- loss of pwr from compromised cable...& shocked the battery w arc welder (suggestion from the NAPA guy) before that I replaced a few fuses, clips/connectors and cleaned up rodent nesting and related in the console to repair a few damaged wires, tested all my relays, etc.....In the end it was clearly an electrical issue; just took a bit of crawling around to troubleshoot, locate, and repair.....& I only lost a little blood