Kobelco SK160LC Seeking input and guidance: Started the machine in the morning. Fired right up...no hesitation. Ran it for an hour and shut it down. Came back to it after an hour and tried to start it..turned the ignition on...had power....turned the key to start...nothing...No sound of the starter trying to turn....just nothing....other than what normally appears on the monitor when turning the power on...but when trying to start...nothing...not even a click. * Checked fuses - all good * Disconnected batteries and load tested each - both good - Reconnected batteries * Turned power back on at the key switch - tried to start - still nothing * Checked for power at the battery relay and at the starter. Powerat both. Banged on the starter - nothing * With power on tried jumping the starter - nothing - ok - bad starter - took it out and saw that the drive pinion was stuck out - had not retracted -must have burnt the starter. * Replaced Starter - ----------------------------------------------------- When I replaced the starter I did not give much or any thought to what might have caused this to happen to the starter and this is where things get interesting. Installed the new starter - Tried starting - NOTHING - same exact nothing as described earlier in this post. Repeated the steps above and when I got to jumping the starter it fired right up - It fired up with a new fault message "EG REV SENSOR". (replaced that straight away - it had frayed wiring making an intermittent connection.) We are a busy facility and since I was able to start the machine by jumping the starter the decision was made to put the machine back to work and continue diagnosing the problem if and when we could. (no input or guidance needed on this point....I get it....and didn't like this approach either) For several years prior to my arrival the machine has been started with a screw driver rather than a key in the original ignition switch...not knowing if this was part of or the problem I thought it would be good to replace it regardless and thus we did. So at this point the machine can be started by jumping the starter and has gone back to work for about a week. After about a week one of the guys is working the machine and loses use of all hydraulic functions and notices the monitor displaying several different fault messages. He tries to shut the machine down at the ignition but when he turns the key to off the electronics turn off but the machine does not shut down...had to shut it down at the engine. I load tested each battery - batteries dead and could not take a charge. Replaced batteries and was able to start the machine at the starter....so....now we are back where we started except that the machine is now also not properly charging the batteries. Downed the machine and looking for resolution. Found that now the battery relay that sends power to the starter went bad....but replacing it did not resolve the issue...still no start. To date we have replaced the following: *Starter *Ignition Switch *Battery Relay *Batteries *Fuses all good Have power - can only start by jumping the starter and won't charge HELP!
Check for continuity from starter back to the relay. If that checks out then from relay to key switch. Somewhere there’s a broken wire. This should help you know which wire is what on your relay. Good luck.
The one thing you've missed is to check the power coming out of the alternator. Running the machine without electrical input will flatten the batteries which then lead to the electronics not working
After a second glance 85 post is usually ground and 86 from switch.
Checked out the battery cables real thorough?
I think you had one fault which has snowballed a bit. Just as a by the way a lot of modern excavators don't have a simple slave relay as shown above but use a safety relay which inhibits the starter if any of the safety switches are not made and also inhibit starting if the alternator is running to prevent engaging the starter when the motor is running. A good auto electrician can do a autopsy on the old starter and determine if the pinion being out was caused by electrical or mechanical. I can walk you through it if you strip it and take pictures. Just based on what you have said my guess would be: Its unusual that you did not hear the faulty starter screaming from being engaged in the ring gear when the motor was running. So I have to assume that did not happen and the solinoid pulled the pinion out and jammed when you tried to start. If the solinoid does not pull out all the way it would stay on its first stage winding which was drawing high current from the (safety/slave) relay for longer than normal. This excess current was probably interrupted by some sort of fusible link in the wiring which probably explains the current no start and also why the alt is not charging. The alt might have its output and connection to the batterys going through the same fusable link. A good multimeter and some checking should find the issue easy. good luck
Thank you for the detailed response. I have the wiring schematic for this machine. In addition to the Battery Relay which is mounted on the bulkhead of the battery compartment next to the glow-plug relay it does show a "safety relay" that shows 2 wires running to it from the alternator on one side of the relay and on the other it shows 1 wire running fron the Battery Relay to the Safety Relay and one wire to the ignition switch. Do you or does anyone know the location on/within the machine of this Safety Relay?
I don't know the location of the relay but I bet if you disconnect the wire to it on the alternator, the engine will probably start. Let us know if that is true.
Like John C says, but look for a post possibly marked D+ or W. It'll be a skinny little wire hanging off there. BTW is your alternator Bosch or Valeo or perhaps Denso?
Look on the starter should be a wire going from this switch to starter solenoid . Bob
the wiring on the starter has two large posts...one with a cable from the battery and a small line connecting the starter motor with the solenoid that is mounted on the starter. the other larger post has a thick guage cable running to the Alternator and anther small/flat copper wire that came on the starter that runs from that post to the body of the starter. the other wiring on the starter is connected to/from the solenoid that is mounted on the starter...essentially.....the starter comes with a wiring harness off the solenoid that connects to a wiring harness of the machine. the wires on the machine side of this harness that connects to the solenoid runs up into and throughout the engine and machine and connects to the ignition switch.
So, how many wires on alt? 1,2? What gauge?
One post with two wires: A larger guage eire from thr starter and a thin guagr wire that connects to a harness that clips into thr alternator. As well, there is a ground from the body and a thin green wire that clips onto a tab on the alternatot....also from the harness
From your explanation the starter is wired wrong. A picture would be very helpful.
Yeah, if you could post a pic of your alt and start wiring, it would help us help you. In the meantime please measure voltage @ green wire at alt.
Thank you.....will do
I pulled the green wire off the R terminal of the alternator to see if the machine would start. Did not start. So in the context of this issue, the alternator is not the problem. The pilot relay on the starter has a two pin harness that feeds from the ignition. Put a test light to each pin on that harness. With the key switch turned to crank/start both wires show positive 24 volts. With the key just in the power on position both show ground. It seems that when turning the key to start the machine one of those wires should be ground and not both positive. Seems to me that somewhere in the starting system ground is being disrupted.
The safety relay is on the plate the ECM is bolted to ,it should be bolted beside it .This behind the seat. The big cables are hooked to solenoid and the small wires are hook to the starter relay ,one of these wires should go to the safety relay.the safety relay grounds the starter relay completing the circuit from the key switch. Bob
Bob, this is very helpful. Thank you. As it stands now, I put the starter back in the machine and repaired the green wire coming off the R terminal of the alternator. I am able to start the machine at the starter and the alternator is producing....shows 28volts at the R terminal/green wire. Is there any detriment to bypassing the alternator safety relay/starter relatinship by nstallng a start button in lieu of cranking at the key switch?....at least for the short term until we can get the machine to a better place to work on it?
If it's your machine, and your only bypassing in an effort to get it to a good place to work on it, I see no problem. It starts, your computers are communicating , all other safety features are in place. Who could complain. I just wouldn't call it a "fix"
Appreciated, understood and agreed
You can unplug the 2 wire plug hooked to the starter relay and check which wire has voltage when you turn the key to start then put a ground wire on the other terminal of the starter relay .This should let you start with the key. Bob
I will try that. I have to figure out which wire that is. I did however remove the green wire off the small tab which is the "R" terminal to see if the machine would start with it disconnected. I was told that if the machine started with the "R" terminal disconnected then the issue would be the alternator having gone bad. Removed the wire from terminal "R" and the machine still did not start. The only other wire it could be is a thin wire that is white and red. this wire goes into the two wire harness along with the thin blue wire off the power post and clips into the alternator. from the alternator that white & red wire runs through a multi wire harness down through the engine where it clips into another set of wires that run forward. I have not yet been able to open that bundle of wires underneath the machine, locate the red/white wire and follow it to its terminus on the other end....presumably, in the cab, behind the seat in what looks like a confused sea of dust laden wires. I will do that at some point soon I hope.
Thank you Bob, I did do that and what I found was that when the key is turned to start both wires show 24 volts which seems to indicate the system has a faulty ground somewhere. Therefore, what I am told is that thus far everything points to the Alternator Safety Relay which as I understand completes the system and if faulty would break the ground and prevent the ignition from starting the machine.
The Alternator is a: "Mitsubishi Electric Corporation" MED17614 A3TN5188 AA 24V 35A 3Z10
Take one wire off the starter relay ,the one on the starter and turn the key to start ,check voltage. Only one wire will have voltage. remove other wire from relay and ground that terminal .should start with key. Bob
The fact that you have power on both sides sounds like you have feedback from what should be the D+ or diode hot side of alternator. I believe this is what you are figuring as"R" I would check wire by wire against wire at safety relay. See which one removes power. Ground that wire. As Bob says, she should fire off with the key. Once you've confirmed that, and shut it off check continuity from safety relay back to alt. Power off/battery switch off ,so you don't hurt your ohmmeter. Is the circuit open? Then check against ground. Then check against power. Which one has continuity?
The safety relay is to protect the starter from trying to start when the motor is running . It is normally closed when the alternator is not running ,so when the wire from the key switch is energized voltage goes thru the starter relay to the safety relay to ground to allow current thru the starter relay to start the motor . When the alternator starts charging it opens the safety relay so you can't try to start motor again . Fairly simple system. Bob
What ended up being the starting issue I have the exact same problem
That white with a red stripe is your alternator charge signal. It should go the the alternator relay in the fuse box. This wire being broken can curse no start because it thinks its already running. I have also seen where the machine would not shut down due to the same issue. They are usually broken where the harness 90s under the engine. That green r terminal is for rpm.
check around your starter area for a broken wire inside the plastic conduit. I had two wires cut by this stuff from all the vibration and shaking of the wire harness. The whole engine bay harness is terrible. This was on a SK170