Kubota U17-3a no crank issue

[jonnyboy74]

Hi Guys
I have an issue with my my 2012 U17-a3 with the D902
I stopped wed afternoon for a coffee, came back and she would not crank,, ign on dash lit up glowplugs buzzer etc no crank,, I am a mech so went through the following and no joy whatso ever about 4 hrs in half machine apart still the same =

A) Used 2nd key and reprogrammed
B)check continuty Ign switch - replaced with new switch ( My local dealer is very good at lending parts but not much use with technical or a wiring diagram )
C) replaced radar antenna on ign switch
D) fed direct 12v to starter and it cranks,,, so ruled out starter - but no start even with ign on,,, also did the 3 wire bypass on ign loom still nothing
E) I have no voltage in crank or continuity on starter crank wire so suspected safety/immobilzer circuit
F) Removed deadmans switch ,,, belled out all ok
G) checked ign feed to deadmans 12v all ok although i note switch works in reverse,, ie it breaks the circuit when lever up and makes the circuit when lever down
so I would like to see the starting/crank circuit to work this out

The only other thing is Start relay,, but need location to check,, other than that I am thinking wiring or the immolizer system

As i say a wiring diagram of start circuit would really help,, and before anyone says,,, yes stop solenoid working but,, been told by kubota it cannot possibly be a stop solenoid issue as it would crank,,, and this is a NO CRANK PROBLEM,,, oh and yes battery is fine,, fuses all good

Any help would be appreciated

Thanks
Jon

 

[Henro]

As i say a wiring diagram of start circuit would really help,, and before anyone says,,, yes stop solenoid working but,, been told by kubota it cannot possibly be a stop solenoid issue as it would crank,,, and this is a NO CRANK PROBLEM,,, oh and yes battery is fine,, fuses all good

Some Kubota engines use a solenoid that must be energized for the engine to run. Others use a solenoid that is energized to stop the engine.

Are you sure the person at Kubota that you talked to knows which set up your engine has?

An electrical diagram would be your friend here…

 

[jonnyboy74]

Some Kubota engines use a solenoid that must be energized for the engine to run. Others use a solenoid that is energized to stop the engine.

Are you sure the person at Kubota that you talked to knows which set up your engine has?

An electrical diagram would be your friend here…

Yep I fully understand the 3 wire pull and hold set up,,,but we are not even at that yet as i say WILL NOT CRANK,, no power to starter or FPS,, and yes I need a wiring diagram,,unless the power to crank has to go through the FPS first before reaching the starter!!!!!!
I now have looms apart and have traced all way from battery inc the immobilizer module which has an additional 12 wires,,, I could also do with ruling out the start crank relay but dont know which one it is out of the 9

 

[North Idaho Wolfman]

Yes the stop solenoid has zero effect on cranking, just the running or stopping once running.

You need to be looking at the Auto release relay, there are 2 one controls the glow plugs and the other controls the starter solenoid.
The relays are here.

 

[Henro]

Yep I fully understand the 3 wire pull and hold set up,,,but we are not even at that yet as i say WILL NOT CRANK,, no power to starter or FPS,, and yes I need a wiring diagram,,unless the power to crank has to go through the FPS first before reaching the starter!!!!!!
I now have looms apart and have traced all way from battery inc the immobilizer module which has an additional 12 wires,,, I could also do with ruling out the start crank relay but dont know which one it is out of the 9

If I remember correctly, on my BX2200, which has a D905 engine, one of the two coils in the fuel cut off solenoid does return to the chassis through the starter. I believe this is the start coil.

You report that you jumped the solenoid on the starter motor and the starter motor turned the engine over, but the engine did not start. If it had started, this would point you in the direction of a safety interlock. But the engine turned over and the engine did not start, and apparently did not even give a hint of starting.

My inclination would be that you could either have a broken wire which goes from the start coil of the fuel cut off solenoid to somewhere, or fuel issue. But a fuel issue doesn’t make sense as the root problem, because the excavator is not trying to turn the engine over to begin with.

Myself, I think I would address the question of why the engine does not start when the engine is turned over by the starter when 12 V is applied to the solenoid terminal. After I got the engine to run, the second thing I would do is troubleshoot the issue of why the engine does not turn over when the key is turned to the start position.

On my BX, It’s possible to remove the fuel, cut off solenoid and watch it when the key is turned to start and then returned to the run position. You can visually verify correct operation of the solid. In your case, you could probably verify the operation of the fuel cut off solenoid easily because you wouldn’t have to worry about the engine starting and needing to shut it down, because it’s not turning over from the key.

Just a couple thoughts…

 

[jonnyboy74]

I spent another hour on it and rigged power probe up to energise FPS it makes a clear click when ign is on although no ignition feed at all to Solenoid,, I am thinking some sort of inhibit is still the issue,, its a UK machine and has an anti theft system on it I have started opening looms and the Control unit for the immobilizer id connected into the ign and safteys so not as easy as it sounds,,, I did get it to run for about 2 seconds with my power probe leads connecting starter exciter and fuel pump solenoid and when ignition is on and you throw the probe switch it cranks and runs but as I only energised the pull or crank element of the solenoid as soon as i let go of switch it stopped,,, this indicates FPS is ok I would say,, although it has a RPM sensor in the fuel pump as well,,, with yet another 3 wire loom,,, not sure if this could be an issue as it is with some larger newer machines,,, no rpm signal,,

Yes the stop solenoid has zero effect on cranking, just the running or stopping once running.

You need to be looking at the Auto release relay, there are 2 one controls the glow plugs and the other controls the starter solenoid.
The relays are here.

View attachment 126727

HI,,, I found where the relays are but could do with knowing which relay is which as there are 8 small black relays and the Glowplug relay is the large grey relay which is ok

 

[TJP440]

I spent another hour on it and rigged power probe up to energise FPS it makes a clear click when ign is on although no ignition feed at all to Solenoid,, I am thinking some sort of inhibit is still the issue,, its a UK machine and has an anti theft system on it I have started opening looms and the Control unit for the immobilizer id connected into the ign and safteys so not as easy as it sounds,,, I did get it to run for about 2 seconds with my power probe leads connecting starter exciter and fuel pump solenoid and when ignition is on and you throw the probe switch it cranks and runs but as I only energised the pull or crank element of the solenoid as soon as i let go of switch it stopped,,, this indicates FPS is ok I would say,, although it has a RPM sensor in the fuel pump as well,,, with yet another 3 wire loom,,, not sure if this could be an issue as it is with some larger newer machines,,, no rpm signal,,

HI,,, I found where the relays are but could do with knowing which relay is which as there are 8 small black relays and the Glowplug relay is the large grey relay which is ok

 

[TJP440]

I had a similar thing happen on a GR2120. jumped off to move a branch, forgot to disengage the deck so the engine shut off. No biggy (or so i thought). Jumped back on disengaged the deck. key on, all lights etc. not start, no nada????
towed it up to the shop, got out the manual and proceeded to chase my tail for several hours. It was just by chance that I had the voltmeter hooked up and visible. I hit the key with 12.0 or so volts showing. Light gauges etc. all good. When I went to start the battery voltage dropped to 1.0 V. Turned the key off and watched the V slowly climb back up to 12.1 or so.
I am 70 YO, a degreed engineer and have owned a classic car repair and resto shop for over 25 years. So I am not STUPID but certainly felt so after chasing my tail for several hours on what turned out to be a bad battery. I have NEVER had a battery fail so abruptly in my entire life. My understanding is this failure is becoming more common as the battery manufacturers have been cutting costs by using less materials connecting the plates. DUNNO but do post back IF it happens to be the same thing. BTW, this was a factory equipped Kubota battery, not a replacement

 

[jonnyboy74]

I had a similar thing happen on a GR2120. jumped off to move a branch, forgot to disengage the deck so the engine shut off. No biggy (or so i thought). Jumped back on disengaged the deck. key on, all lights etc. not start, no nada????
towed it up to the shop, got out the manual and proceeded to chase my tail for several hours. It was just by chance that I had the voltmeter hooked up and visible. I hit the key with 12.0 or so volts showing. Light gauges etc. all good. When I went to start the battery voltage dropped to 1.0 V. Turned the key off and watched the V slowly climb back up to 12.1 or so.
I am 70 YO, a degreed engineer and have owned a classic car repair and resto shop for over 25 years. So I am not STUPID but certainly felt so after chasing my tail for several hours on what turned out to be a bad battery. I have NEVER had a battery fail so abruptly in my entire life. My understanding is this failure is becoming more common as the battery manufacturers have been cutting costs by using less materials connecting the plates. DUNNO but do post back IF it happens to be the same thing. BTW, this was a factory equipped Kubota battery, not a replacement

Funny you should mention this,, as it crossed my mind even though I performed HD test on battery and was reading 12v plus,,, so I connected jumper up and was still the same infact same jumper been on it all day and when i got it cranking it was fine,,, but your right the old battery story has been the cause of many a red face just like the empty fuel tank but the guage shows full,,,

 

[TJP440]

that is where i failed, not doing a load test (SPANK) but I've just never had a battery fail like that.. Good luck in your quest

 

[North Idaho Wolfman]

I don't have the exact WSM for your model Ex, but I would just test all the relays, as they are all the same.

 

[jonnyboy74]

I don't have the exact WSM for your model Ex, but I would just test all the relays, as they are all the same.

I was going to trace circuit between crank on key and starter,, will check relays as well,,, just to throw something else into mix and i have never known this before with other electrical non crank issues but does the circuit go through the alternator,,,, only reason i mention the alternator is because I replaced this 2 week ago,,,

 

[North Idaho Wolfman]

I was going to trace circuit between crank on key and starter,, will check relays as well,,, just to throw something else into mix and i have never known this before with other electrical non crank issues but does the circuit go through the alternator,,,, only reason i mention the alternator is because I replaced this 2 week ago,,,

Like I said I don't have the WSM for the U17-3a but the U15-3 shows that yes the alternator does give a signal to the auto release controller, so you might be onto something there.

 

[jonnyboy74]

Like I said I don't have the WSM for the U17-3a but the U15-3 shows that yes the alternator does give a signal to the auto release controller, so you might be onto something there.

Ok so this morning I got it to crank on the key,,,, yipppeee I thought cracked it,,,, but guess what,, will not run
So what i did was I traced the starter or crank relay I also drop tested the supply to ign switch to rule it out,,, all good,, anyway the kubota relays are not numbered and only 4 pin,, but worked out the coil side,,, I loop the realy out and it cranked,,,, so i istantly thought relay,,,,, but no replaced relay still the same,,,
anyhow I know I had plenty fuel as it ran yesterday when I made a loom up to use with power probe,,, so I started agiain on the loom I got to the junction for the Fuel pump sol,, and cannot get any power from loom to the solenoid at all,,, if I could it would run,,, so I am thinking something is inhibitting it including the crank,,, and as i have by passed relay thats why it cranks,,, by this time I had had enough again so back to drawing board,,, but i defo need a wiring diagram

 

[North Idaho Wolfman]

There isn't an cheap, free, safe U17-3a that I can find.
Look at this manual and compare to what you have.
It might give give you some more insight.

KUBOTA U15-3 WORKSHOP MANUAL Pdf Download

View and Download Kubota U15-3 workshop manual online. u15-3 excavators pdf manual download.

www.manualslib.com

 

[jonnyboy74]

There isn't an cheap, free, safe U17-3a that I can find.
Look at this manual and compare to what you have.
It might give give you some more insight.

KUBOTA U15-3 WORKSHOP MANUAL Pdf Download

View and Download Kubota U15-3 workshop manual online. u15-3 excavators pdf manual download.

www.manualslib.com

Thankyou,,,