Excavator, hard starting, unstable low idling, can’t throttle up, keeps running after removing the starter key…

[Taat]

The machine is Takeuchi TB 1140, 2006, with over 12000 hours on it.

This came out of the blue. No signs of any similar problems before that. I started the machine normally, then drove 10 minutes to my neighbor. As I arrived I had to disengage the key two times for it to turn off. After that it was hard to start. After we managed, the rpm were very low almost wanting to turn off but not quite. No throttle control was possible, but can hear and feel the throttle motor working when trying to raise rpm on controls. Can’t turn off the machine without emergency shut off cable connected to the injection pump. Can raise the rpm but have to manually assist on the injection by forcing the lever where the cable from the throttle motor is connected. When manually raising the rpm to the max, I they are able to drop to medium when pressing the medium button but not to the low rpm, even though the light is flashing on low rpm but it stays at around medium. After that it started normally but couldn’t turn off with the key and the rpm wouldn’t drop to the low. The next day there was again hard starting and had to manually raise the rpm but I only did to the about minimum, after removing the key the machine would turn off but would also if I would switch the rpm to the low.
It almost feels like the cable from the throttle motor to the injection pump is getting stuck? Or is there some electrical problems causing the throttle motor and cable to not be set at correct position? Is the injection pump the problem with the throttle lever being stuck and the cable is unable to pull it efficiently? I would really like some opinions on this.

 

[V8Druid]

stop solenoid faulty??

 

[Taat]

stop solenoid faulty??

Maybe… do you know where that would be usually mounted?

 

[V8Druid]

Maybe… do you know where that would be usually mounted?

on the injector pump .. 'fraid I don't know the machine to give any better description ..... anyone?????

 

[Taat]

I am not at the machine, but if I remember correctly there weren’t any wires to the injector pump. I will try to check the electric diagram for it

 

[Canal Navvy]

Disconnect the control cable from the pump and manually run the rack from shut off to full throttle. 12000 hours is a long time for a Bowden cable to last (if it is the original)

 

[V8Druid]

I am not at the machine, but if I remember correctly there weren’t any wires to the injector pump. I will try to check the electric diagram for it

quite possibly all done on the rack with the throttle actuator then, as Canal Navvy infers above ... 's a good shout if that's the case ... as said, I have no experience of the machine model, just chucking out generic ideas

 

[mart1602]

stop solenoid was my 1st thought also but electric throttle could be at fault

 

[Taat]

Thanks for all the advices up to now. I will try to remove the cable tomorrow. I was rebuilding the pump a month ago and have been moving the cable around when taking the pump off and mounting it back on.
One thing I noticed prior to that is that when turning the machine on sometimes the beep when preheating had a higher pitch than usual. And when this problem appeared I noticed that sometimes this short beep would occur when activating the lever lock for hydraulics. Is it possible that there is an electrical problem connected to that?

 

[Steve]

Thanks for all the advices up to now. I will try to remove the cable tomorrow. I was rebuilding the pump a month ago and have been moving the cable around when taking the pump off and mounting it back on.
One thing I noticed prior to that is that when turning the machine on sometimes the beep when preheating had a higher pitch than usual. And when this problem appeared I noticed that sometimes this short beep would occur when activating the lever lock for hydraulics. Is it possible that there is an electrical problem connected to that?

Check output voltages of battery & alternator especially if the shutoff solenoid is powered off through a time circuit like some kubotas . My bet on a 12k hr machine is lack of amps from corrosion on a terminal or connector .

 

[Taat]

Check output voltages of battery & alternator especially if the shutoff solenoid is powered off through a time circuit like some kubotas . My bet on a 12k hr machine is lack of amps from corrosion on a terminal or connector .

I have also changed the batteries this year and have measured the voltage when this problem occurred. I think the results were about 25V with machine turned off and up to 27V when running and alternator supplying.

 

[Taat]

So the guy that has gave me advice when rebuilding the hydraulic pump has been through some Takeuchis and said that the “governor lever” on the injection pump is being stuck by some “particles” building up inside and throttle motor not having enough power to pull and release. It is probably fixable without needing to readjust the injection pump later. Will keep you guys updated on this. This is the best that I can explain currently. I don’t know how to express exactly with technical terms.

 

[Taat]

So with the cable disconnected, the injection pump lever works fine, also the throttle motor doesn’t struggle and sets the idle position for starting fine. So I guess the cable is at fault.

 

[Taat]

Yup it was a cable. I could hardly move the old one in a vice with help of some levers. The new one was smooth, installed it today, works like before this problem. Thanks for all the help. Appreciate it!

 

[Mick-the-fitter]

Can you send a picture of the throttle linkage at engine end

 

[Canal Navvy]

Probably worth checking the earthing from the engine to the machine frame as it's not unheard-of control cables being fried by having to share the earth return from the starter motor

 

[Taat]

Can you send a picture of the throttle linkage at engine end

 

[Taat]

Best pictures I have on my phone. Thick one is throttle cable the other is emergency shutoff.

 

[V8Druid]

unusual for those teleflex type cables to seize/freeze up .... wonder if as said earlier it's had some starting current down it?

 

[Taat]

unusual for those teleflex type cables to seize/freeze up .... wonder if as said earlier it's had some starting current down it?

Well could it be that when putting the pump back in I didn’t set the cable as it was and was in contact with the pump while the oil was heating up, causing the cable failure?

Probably worth checking the earthing from the engine to the machine frame as it's not unheard-of control cables being fried by having to share the earth return from the starter motor

I will try to check that also.