hello everyone. I ran my JS240 out of diesel yesterday and subsequently burnt out a very expensive solenoid trying to start the thing again. Now my excavator won't even show any signs of life when I turn the key, apart from electronic instruments. Is the fuel shut off solenoid part of the start up circuit ? Is there any way I can jump the plugs with wire to operate without it? It appears to be $600 Aud Thank you
Can you get the part straight from Isuzu?
some I am familiar with..... 3 wire, earth, hold coil & energise coil. The latter is high power and could well burn out if energised too long. Test it. The solenoid should retract when energised. Quick fix... remove it & see if the engine starts. To stop.... there is a small plate in the housing that the solenoid pin pushes... so poke that! Put a temporary plate over the hole to stop grit entry.
Are you saying the motor doesnt crank anymore? I dont think its to common to burn a shutoff solenoid running out of fuel but a starter maybe or even a fuse link or fuse if it was cranked on a while Did it ever start after running out of fuel
Hi everyone Stop solenoid is completely burnt out. Upon my research I have found that burning out these coils is a very common problem by operators not fully aware that they should not hold ignition on for more than 30 secs or so. Ok damage done. But machine won't crank. So here is what happened, I eventually primed enough fuel and got it running,, but before it started the damage was evident with a cloud of toxic insulation smoke. There must have been a slight delay as I operated the machine for 3 hours before shutting down for more fuel. When I returned it would not start and I saw that the 3 leads of the stop solenoid were burnt all the way back to the plug, No insulation left. I have studied heaps and I've narrowed it down to either, : 60 A fuse link fried ECM recognises solenoid is fucked and won't let me start until solenoid completes circuit or The relay may be burnt out. I was leaning toward the 60 A fuse link. But certain schematic show that the battery runs straight to the solenoid as part of the circuit. At least to my untrained eye. I have attached some schematics below.
And start process in writing. Thank you
The ecm has no idea the solenoid is faulty and does not have to complete any circuit. When the pull in coil burnt and shorted it also would have caused the hold in coil to short and over heat as well. The result being the ignition on circuit from the key switch through the ecm to the hold coil has had fault current applied to it. Additionally the cranking circuit down through the starter inhibit relay and then on to the pull in coil also had fault current when the coil burnt. Prob fried the start inhibit relay in the process. Is a simple job to use bulb or multi meter at the starter motor inhibit relay and determine which circuit has no power when the key is turned to the cranking position. Power should be present on the Black and White wire when you are attempting to crank engine. Regards
Thank you for the reply. I did not have my circuit tester at the time and the job is a 2 hour drive away in horrendous traffic. I will take it up today and test. Unfortunately it is a public holiday so I can't order new part. By starter inhibitor relay do you mean what is labelled 'battery relay'? Can I bypass to start without causing further damage until I can order new relay? Thank you
Hmm, may be a bit risky. Might be safer to just wait for the part.
Hoping that the 60 amp fuse link would fry before the relay however, considering the price difference between the two it would make sense to protect the $150+ relay with a $4 fuse.
The way I read that schematic is when you power up the starter relay that relay also directs power to the pull circuit of the shutdown solenoid. If that's correct, then yes, if you cranked the engine from more than a few seconds, 30 seconds for sure, it would fry the pull coil circuit on the solenoid. Real bummer this happened to you antpoo, but I have to say, and you've prolly already had this heated conversation with yourself (I know I would myself), generally not good to run a diesel out of fuel for a number of reasons as they all have their quirks when this happens. Sadly, it appears you found one of those quirks with your machine. I hope you get it sorted out bro.
Thanks for your reply. I hate running machine low on diesel, but thieves come and steal it when you leave onsite. Not always, but the last thieves didn't bother to leave even my fuel cap and they ditched it. Now I use a cup to cover from the rain. It has left a psychological scar, and now I run only enough fuel for what I think I will need. It sucks, but diesel is so expensive I run the gauntlet. This time I bugger up and it cost me. The question though, do I even need the stop solenoid to complete the crank circuit? I lost the arm on the stop solenoid over a year ago so it basically did nothing anyway. I'm getting power to the relay on 3 prongs out of 4 when key set to ignition, I also have power to the starter, but I do not have a second pair of hands to push key to crank.
Im not sure how you could have power on three but is hard with out seeing what you are doing. Before stop solinoids came along you would pull a cable to stop engine so no big deal. Is only inportant if the engine management has the ablility to stop the engine for some other critcal event. As for the starter inhibit relay i think is a load of crap. Its only purpose is to monitor the run state of the alternator and prevent cranking an already running engine. If you are dumb enough to do such things you realy should not be operating heavy machiney. You can do away with that relay if need be. Cheers
Narrowed it down to stater relay. All leads to the starter relay light up under 'crank'. But apar from a click, nothing happens.
Sorry, mate, I was confusing the round metal battery relay with the starter relay on the starter motor. The battery relay has four prongs, the one that did not show on the test bulb was feeding alternater so no surprise why it wasn't lighting up. I'm familiar with car starters where a solenoid is used to fire the starter motor. I'm not sure if the 'relay' just another word for solenoid, or heavy machinery stater motors have both a relay and solenoid. Either way, relay or solenoid, I think it is toast.
I can understand your confusion . . . In the U.S. commonly a 'solenoid' -moves something- which is -normally- a shaft/rod or something -not electrically connected-. However a 'relay' -attracts something- that has -contacts attached/embedded- that which make/break an electrical connection. IMHO - - - - RELAYS -relay- a voltage/current to another device. SOLENOIDS - move something magnetic.
There is no set rules regarding naming but generally a relay is an electrical switching device and a solenoid usually moves something. But when a device has multi functions they generally call it what what its main function is to give people a clue. Example, A solenoid on the top of a normal starter motor uses the plug core to pull the pinion into the ring gear of the motor and then closes an electrical set of contacts on the end cap. The small relay near the starter solenoid has two functions, inhibit the cranking circuit and shield the heavy current drain of the starter solenoid from the EX wiring. So in normal convention it should be called a starter inhibit relay but i have seen it called all sorts of things in the circuit diagrams. The wire you refer to going to the alternator does not feed the alternator. When the alternator is running the alternator applies a voltage back to that relay and a small electronic circuit within the relay senses the voltage present and locks out the circuit that engages the starter solenoid. Since there are millions of cars on the road without this feature it puzzles me why the earth moving industry need such protection. (The manufacturers must think monkeys are at the controls?) If you chose to do away with that relay you will have to use a small $5 relay there to prevent overloading your crank circuit . I can walk you through that if you go that way. Cheers
Thanks for the advice everyone. I have auto electrician coming today, he asked whether I bridged the solenoid to see if starter cranked and this I hadn't done as It's kind of difficult to get to until I remove some covers. That would confirm 100 % . Will have news this afternoon. Also I have now been told by multiple sources that it is cheaper to replace whole starter motor than to change the solenoid. This is a painful learning curve, But lessons have been learnt.
Around here there is a starter safety relay which is as described by 007 prevents the starter from being engaged into the flywheel when the engine is running. In my experience it is typically found on Japanese built machines except for Cats. Cat uses a one time key switch which has to go to the off position before you can go to the start position again. I've had to wire out the safety relays on some machine to get them working until I got a new part. I don't recommend doing that for any amount of time as chances are someone will not hear the engine running in a noisy environment and hit the starter.
Hi 007 Just reread your reply, and realised you appear to say there is a relay prior to the solenoid? If so, could it be that this has gone and my starter solenoid and starter will not need to be replaced? Fingers crossed, I hope you are right.
Hi antpoo, You are correct. Unless the starter motor was engaged for an extraordinary amount of time the starter and its solenoid will be fine. It will be the small relay near the starter with the 5 terminals which had the fault current applied to the relay contacts. If you bridge out the two terminals on the right shown in your circuit diagram the starter motor should engage. Cheers
Hello all Problem solved, but it was worst case scenario. Starter motor $700 installed. I tried to bridge starter motor and got a load of sparks only, as in a direct short. Removed starter and all the copper bits fell out and the rest was black. Here is how it happened. Ignition cranking too long over heated stop solenoid and melted insulating wires, they now were touching each other and one of them (the pull) was a direct link to the starter solenoid! It seems that if I had only unplugged and removed the stop solenoid from the circuit I would be saved, but instead for two hours the stop solenoid pull wire was touching the others and gave the Starter motor a crank signal, and it proceed to burn itself to pieces. See pic below. Thank you for your help, I hope this thread serves to inform others unfortunate enough to be in similar situation.
Good to hear you have it under control. Just as a by the way the damage shown in the picture of the starter is more than just being energized. The starter was not operating electrically with no commutator or brushes. The only way normally the commutator flyers to pieces from over revs and destroys all the brush boxes like that is the pinion being stuck in mesh with the ring gear with the motor running and that damage probably happened in about 30seconds not hours. There would have been a loud screaming noise coming from your starter during this process until the pinion clutch seized and over revved the armature. Im not sure i agree with your theory as if the starter was given a crank signal the inhibit relay would not have engaged the starter with the engine running. I think more likely the starter solenoid became overheated and locked in keeping the pinion engaged and also sending power to the stop pull in circuit and it all went down hill from there. Any way at least you are away again. Cheers.
Hi 007, After the wires burnt, it actually started normally and I operated it for nearly two hours before shutting down. Thus, it did indeed stick in the ring gear and tear to pieces, but because I was far away in the cab with the engine running I did not hear this. Because the pull wire from stop solenoid had a direct link to the starter, the relay that protects from secondary over crank was bypassed when it became energised when it touched the bare push wire and the stop solenoid basically became a make shift fuse for the starter itself. It engaged starter, and destroyed, and I did not hear a thing. So the lesson learnt, if you overcrank and melt wires on the stop solenoid, do not risk starting machine again, even if it starts, because the risk is too great that the wires will short each other and energise starter motor while engine running. There is simply no protection available for if this happens. Thank again.