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Thread: JCB 3CX - 1986 Wont Start

  1. #1

    JCB 3CX - 1986 Wont Start

    Hi all,

    Used the digger all weekend and the last thing yesterday afternoon I managed to get it stuck!! Anyway, it is now sat at an odd angle and the engine stopped running. I suspect the issue is that since it was low on fuel the fuel is not now reaching the outlet pipe. I have topped it up with plenty of fuel now but it still refuses to start. I suspect it needs bleeding but not sure how this is done?

    My plan was to maybe crack off each of the injectors and crank it over but not sure whether this procedure will work?

    I have checked that there is diesel reaching the pump and this seems OK, and the sight glass at the filter housing looks full; is there a bleed screw on the filter housing somewhere?

    Any other tips on how to bleed it?

    Also, what does the small lever under the fuel pump do?

    Thanks

    D

  2. #2
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    Re: JCB 3CX - 1986 Wont Start

    Follow pipes into the injector pump in reverse to see what you have there. You might have single or double fuel filter and/or sediment bowl. Locate the lift pump on the side of rhe block. Open any screw/small student on the top of the first component after the lift pump and then use the lift pump manually. If all goes well work through to bleed screws on the injector pump closing each bleed point before moving onin . If you have a good flow close the last bleed screw slack of one injector pipe at an injector and crank. You might get lucky! You will not have any smoke if you have not got the fuel through.

  3. #3

    Re: JCB 3CX - 1986 Wont Start

    Quote Originally Posted by essexpete View Post
    Follow pipes into the injector pump in reverse to see what you have there. You might have single or double fuel filter and/or sediment bowl. Locate the lift pump on the side of rhe block. Open any screw/small student on the top of the first component after the lift pump and then use the lift pump manually. If all goes well work through to bleed screws on the injector pump closing each bleed point before moving onin . If you have a good flow close the last bleed screw slack of one injector pipe at an injector and crank. You might get lucky! You will not have any smoke if you have not got the fuel through.
    Thanks Pete.

    When you say use the lift pump manually is this the small lever underneath the pump on the side of the block?

    I cant feel much resistance in this at all, it waggles up and down with ease.

    D

  4. #4
    Senior Member wr.'s Avatar
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    Re: JCB 3CX - 1986 Wont Start

    On our 1983 3CX there was a fuel filter under the engine in between the chassis which filled with crap the first time we ran her dry. She would not bleed through until we found that filter and cleaned it out or changed it (can't remember which) When the lift pump is just as you describe there is often no fuel available for it to pump. She might have sucked dirt into the outlet pipe in the fuel tank. Can you take off the inlet to the lift pump and blow back to the tank?
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  5. #5
    Senior Member Footsfitter's Avatar
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    Re: JCB 3CX - 1986 Wont Start

    Quote Originally Posted by wr. View Post
    On our 1983 3CX there was a fuel filter under the engine in between the chassis which filled with crap the first time we ran her dry. She would not bleed through until we found that filter and cleaned it out or changed it (can't remember which) When the lift pump is just as you describe there is often no fuel available for it to pump. She might have sucked dirt into the outlet pipe in the fuel tank. Can you take off the inlet to the lift pump and blow back to the tank?
    Or the pumps internal lever is right up on top of the camshaft lobe? gently turn the engine over while trying the lever and you should find that some resistance comes back to the lever where the cam has released the pumps internal lever allowing you to actually pump by hand.
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  6. #6
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    Re: JCB 3CX - 1986 Wont Start

    I had an 87 grey cab which was an absolute pig to start after being run dry.

    Filters had been changed, connections secured to cut-off solenoid, new filters, etc, etc. Run 100%, just a total bollicks if ever run out.

    Then I located the wee sediment trap stuck down in between the chassis and the gearbox on the right hand side covered in crud and well disguised. Needless to say it was as full of crap as it could stick, a miracle how the thing run at all, but it did.

    Once cleared all bleeding problems disappeared.

  7. #7

    Re: JCB 3CX - 1986 Wont Start

    Thanks chaps.

    I managed to get it going last night (in the pitch dark!!).

    Basically checked all of the fuel flow from the pump to the filter housing, out of the filter housing to the diesel pump. Then removed the plate that holds the dipstick on the diesel pump and behind this plate are 2 bleed screws. Undid the bleed screws and pumped fuel through from the lift pump. Then hey presto, it started up!!

    Regards

    D

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