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  1. #1
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    JCB JZ140 engine error codes

    Hoping the BFF Brains Trust can help, and as is sometimes the case, what seems to be a simple problem might have an alternative solution. I'll tell the long story, coz sometimes the long way around is the quickest way home.

    A used machine, (I understadn a JZ140 is a JZ130 with a blade attached) bought a couple of years ago, 9k hrs, from a reputable hire company (so presumably it was well serviced). When I was last using it several months ago, the engine began to run on when the key was switched off. It was common that I would also have to use the emergency stop button. The engine would almost stop, then pick up a few revs, then almost stop again, repeatedly. An intermittent fault which did not always occur. I would stop it by manually pulling the stop solenoid cable.

    Move on a few months, and one battery died several months ago. Hooked up the one good battery to keep the display memory alive until the second battery was installed today. Meantime, I looked at the stop solenoid and noted some clean threads on the bolt anchoring it to the frame, so I assumed the solenoid had moved enough that it did not pull the pump stop lever far enough.

    Today, the engine started instantly, as normal, but ran only at the almost-stopped speed. The electronic throttle would not work, and the display showed the error code "108 flywheel".

    I found the flywheel sensor, disconnected and reconnected it, ensuring the two parts were fully connected. It made no difference.

    I'm guessing that hte problem is analogue, not digital i.e. intermittent (but now continuous) loss of signal, not a computer or software problem.

    I'm assuming the solenoid is not the problem, coz it now in evidence at start-up, not just at shutdown, so I'm hoping someone can point me to a list of error codes. The service manual says nowt, and the parts book simply lists the engine speed sensor as a spare part (which is an eye-watering price!).

    On that latter comment, I presume it is a generic sensor, used widely on the Isuzu engine fitted, so an Isuzu part number could be useful if it is a sensor problem. I have *no* experience with flywheel sensors!

    JV
    Agtronix - the home of the Weedswiper

  2. #2
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    Re: JCB JZ140 engine error codes

    On further thought, is the flywheel sensor simply reporting that the engine is turning over at too slow a speed (for whatever reason) or is it controlling that speed by having failed, or has something else failed preventing the electronic throtle operating? Maybe I'll try manually moving the throttle arm on the injector pump tomorrow.

    JV
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  3. #3
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    Re: JCB JZ140 engine error codes

    Quote Originally Posted by john maddock View Post
    On further thought, is the flywheel sensor simply reporting that the engine is turning over at too slow a speed (for whatever reason) or is it controlling that speed by having failed, or has something else failed preventing the electronic throtle operating? Maybe I'll try manually moving the throttle arm on the injector pump tomorrow.

    JV
    Problem solved - I think!

    First, disconnected the flywheel sensor - starter wouldn't operate, so I established that the computer needs a signal.
    Tried wedging the throttle open a bit - cannot move it.

    Then disconnected the sheath of the stop cable, and the stop lever on the pump moved a good 25mm forward. Engine started, throttle control works.

    So... I had already adjusted the solenoid end-stop bolt to the maximum, supposedly allowing more movement of the cable, and there is no adjustment left on the sheath end clamp, so maybe the cable is not running freely in its sheath. I'll try to get the cable assembly vertical & drip some Ballistol down for lubrication.
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  4. #4
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    Re: JCB JZ140 engine error codes

    Quote Originally Posted by john maddock View Post
    Problem solved - I think!

    First, disconnected the flywheel sensor - starter wouldn't operate, so I established that the computer needs a signal.
    Tried wedging the throttle open a bit - cannot move it.

    Then disconnected the sheath of the stop cable, and the stop lever on the pump moved a good 25mm forward. Engine started, throttle control works.

    So... I had already adjusted the solenoid end-stop bolt to the maximum, supposedly allowing more movement of the cable, and there is no adjustment left on the sheath end clamp, so maybe the cable is not running freely in its sheath. I'll try to get the cable assembly vertical & drip some Ballistol down for lubrication.
    Google says that the error code is -
    The flywheel sensor is reporting an engine speed even though the engine is not running.
    I'm assuming your solenoid is the rack-puller type direct onto the injection pump stop, or via a control cable to the stop lever? First, our 456zx shovel with a cummins power unit has a rack puller and it is very voltage sensitive- the starter will operate when the batteries (24v) are going down but the 1st thing to fail is there isn't enough voltage to hold the puller/solenoid in the run position.

    I'd disconnect the solenoid and see if the engine starts and behaves normally? I think the low speed may not of kicked the alternator into charging- it may affect the dash/controls/ecu from actually working? With the solenoid unhooked (not the loom- just to the stop lever) get the engine running and if alls ok then look into the solenoid and its control cable for adjustment and that sticky cable, then hook it back up to try again.

    The 456zx genuine rack pullers are over 600- Chinese copies are about 10% of that delivered in 10-14 days, we have had 2 chinese ones in 9 years so not too bad a service. When we have had issues with it and been caught out, we leave the puller wired up but have a pull cord on the pump stop lever thats hooked over a convenient point for run, and to stop - simply pull it off the hook!

    Also check your batteries are both ok, and that when up and running the alternator is doing its stuff ok- they can affect all sorts of things from voltage drop to no signal to the rev counter affecting the electronics. Also if you get an odd flat battery(s) a fault in one of the alternators 3 rectifier diodes can flatten a battery while stopped and /or play havoc with charging.
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  5. #5
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    Re: JCB JZ140 engine error codes

    Quote Originally Posted by Footsfitter View Post
    Google says that the error code is -

    I'm assuming your solenoid is the rack-puller type direct onto the injection pump stop, or via a control cable to the stop lever? First, our 456zx shovel with a cummins power unit has a rack puller and it is very voltage sensitive- the starter will operate when the batteries (24v) are going down but the 1st thing to fail is there isn't enough voltage to hold the puller/solenoid in the run position.

    I'd disconnect the solenoid and see if the engine starts and behaves normally? I think the low speed may not of kicked the alternator into charging- it may affect the dash/controls/ecu from actually working? With the solenoid unhooked (not the loom- just to the stop lever) get the engine running and if alls ok then look into the solenoid and its control cable for adjustment and that sticky cable, then hook it back up to try again.

    The 456zx genuine rack pullers are over 600- Chinese copies are about 10% of that delivered in 10-14 days, we have had 2 chinese ones in 9 years so not too bad a service. When we have had issues with it and been caught out, we leave the puller wired up but have a pull cord on the pump stop lever thats hooked over a convenient point for run, and to stop - simply pull it off the hook!

    Also check your batteries are both ok, and that when up and running the alternator is doing its stuff ok- they can affect all sorts of things from voltage drop to no signal to the rev counter affecting the electronics. Also if you get an odd flat battery(s) a fault in one of the alternators 3 rectifier diodes can flatten a battery while stopped and /or play havoc with charging.
    Thanks FF - good points all, as usual

    The injection pump is an in-line unit, and the solenoid pulls the stop lever via a Bowden type cable about 750 long. Several applications of Ballistol through the day, plus movement, has freed the cable in its sheath. With the cable disconnected from the lever, the engine starts & runs normally.

    It is clear the flywheel sensor is not the problem; it simply reported
    that the flywheel was running slow, so the computer disabled the throttle.

    The problem is that the solenoid is not pulling the engine-stop lever far
    enough. Two possible reasons: one or both adjustments have moved, or the
    cable has stretched e.g. by fraying as a result of binding in its sheath.

    There are two adjustment places, one each side of the solenoid. The outer
    one, at the "back end" of the solenoid, appears to be to limit the travel
    of the solenoid shaft when it is energised. Tother is on the engine side
    and appears to determine how far the stop lever is moved i.e. it shortens or lengthens the cable.

    I've backed the first almost right off, but even so the engine still does
    not quite stop coz the lever is not pulled far enough.

    The other adjustment is a problem, coz although there is maybe 12mm of thread
    available, I cannot undo the locknut on the adjuster partly coz of it's location
    and partly coz I don't have two open enders which fit tightly.

    Normally in that situation I'd look to removing the complete assembly so I could get it in the vice, but
    the idiot in there before me has damaged the slots on the Phillips head
    M8 screws holding the solenoid. And did I mention the need for key-hole surgery skills?

    Your idea of a rope from the stop lever is looking good at the moment!

    JV
    Agtronix - the home of the Weedswiper

  6. #6
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    Re: JCB JZ140 engine error codes

    Yes, sounds like it the solenoid, either its been set up wrong or its adjustments have moved, or perhaps the solenoid has an internal issue? or is packing up?

    Also can you hook up the solenoid and energise it to see if it can/will hold the stop in the run position? Had them where they will "pull" but only half hearted - give them a bit of assistance on the stop lever and it would run, release the assistance and down it goes or stops.
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