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Kobelco SK160LC -Can only start by jumping the starter and won't charge

Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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! :)
 

BigWrench55

Senior Member
Joined
Oct 11, 2018
Messages
1,176
Location
Somewhere
90936510-34F5-40C6-8F32-90B86E89A476.jpeg 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.
 

Tones

Senior Member
Joined
Mar 15, 2009
Messages
3,059
Location
Ubique
Occupation
Ex land clearing contractor, part-time retired
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
 

007

Senior Member
Joined
Dec 28, 2016
Messages
280
Location
Australia
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
 

Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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 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
 

John C.

Senior Member
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Jun 11, 2007
Messages
12,865
Location
Northwest
Occupation
Machinery & Equipment Appraiser
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.
 

funwithfuel

Senior Member
Joined
Mar 7, 2017
Messages
5,519
Location
Will county Illinois
Occupation
Mechanic
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?
 

Bluox

Senior Member
Joined
Jun 19, 2010
Messages
1,960
Location
WA state
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?
Look on the starter should be a wire going from this switch to starter solenoid .
Bob
 

Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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.
 

Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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


So, how many wires on alt? 1,2? What gauge?
 

funwithfuel

Senior Member
Joined
Mar 7, 2017
Messages
5,519
Location
Will county Illinois
Occupation
Mechanic
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.
 

Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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.
 

Bluox

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Jun 19, 2010
Messages
1,960
Location
WA state
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
 
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Tugboat Trash

Member
Joined
Aug 11, 2018
Messages
12
Location
westbury, ny 11590
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?


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
 
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