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Thread: NH 8340 weird dash and won't start

  1. #1
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    NH 8340 weird dash and won't start

    Hi, I have a '98 8340 SLE and having some trouble. Something caused the display to reset tractor hours to zero the other day and my speed reading is showing that I'm going faster than I really am.

    Now yesterday when I to start it it fired up for a second and then shut down and wouldn't start, just cranked over without firing. I checked all my fuses and kept trying and all of a sudden he started and then was good to use for a few hours.

    Then yesterday evening I went to start him and it did the same thing but this time never started at all. I checked and cleaned battery cables and even tried using a jump wire on the fuel shut of solenoid, nothing.

    The other weird thing is when trying to start it the display shows fuel level and hours first as default instead of oil pressure and engine rpms.

    Any ideas?

  2. #2
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    Re: NH 8340 weird dash and won't start

    Don't know about the dash problem but if you run a live wire to the fuel solenoid and it still didn't start,either the solenoid is faulty or you have a diesel system problem.. Does the solenoid click when energised? Also try disconnecting the oil pressure switch wire and crank it.I'm not sure,but if oil pressure isn't sensed it may prevent starting but with a jumper wire to the fuel solenoid,it should override that safety feature.
    It sounds like your dash has went wonky or the ecu has a fault but still with a seperate wire to the fuel solenoid the engine isn't linked to the ecu and it should start. Also wonder if the alternator has sent a spike of higher current through the system and fried something?

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    Re: NH 8340 weird dash and won't start

    If the ECU is acting up could it also not be registering the shuttle in neutral?

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    Re: NH 8340 weird dash and won't start

    Not sure ep,but the only link to the ecu and engine would be finally through the fuel solenoid wire.So a completely seperate live to the FS from the battery should make it click,let fuel through and even if need be,cross the starter and the engine should start.If it doesn't,there has to be a duff solenoid and/or no fuel getting through. Or a completely blocked air filter of course.......

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    Re: NH 8340 weird dash and won't start

    Quote Originally Posted by agrimax View Post
    Not sure ep,but the only link to the ecu and engine would be finally through the fuel solenoid wire.So a completely seperate live to the FS from the battery should make it click,let fuel through and even if need be,cross the starter and the engine should start.If it doesn't,there has to be a duff solenoid and/or no fuel getting through. Or a completely blocked air filter of course.......
    I see what you mean.

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    Re: NH 8340 weird dash and won't start

    well it worked for a couple days and now it's acting up again. I replaced the fuel shut off solenoid with the updated version and have even tried jumping the solenoid with a wire straight from the battery and nothing. Fuel filter isn't that old, just from this summer. I don't think it's reading the transmission in gear, anything else that would prevent starting?

  7. #7
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    Re: NH 8340 weird dash and won't start

    do these tractors have a lift pump somewhere?

  8. #8
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    Re: NH 8340 weird dash and won't start

    Quote Originally Posted by SaskFarmer View Post
    well it worked for a couple days and now it's acting up again. I replaced the fuel shut off solenoid with the updated version and have even tried jumping the solenoid with a wire straight from the battery and nothing. Fuel filter isn't that old, just from this summer. I don't think it's reading the transmission in gear, anything else that would prevent starting?
    Quote Originally Posted by SaskFarmer View Post
    do these tractors have a lift pump somewhere?

    UK models IIRC had a hand priming pump on top of a filter? - round metal thing with a black knob to press, the actual "lift pump" is in the injection pump - think internal primary pump before going into the actual rotary injection section of the pump.

    if you power the shutoff solenoid direct from the battery and the battery is well charged then it should start, if it doesn't, try hooking up a pvc hose from a clean container of diesel to the feed pipe to the manual lift/priming pump and see if that helps, if you still have a non starter, try using a hand primer pump with some pvc hose direct into the fuel filter




    The clear hose will enable you to bypass the proper steel tubing and hoses and get it running, then check out what is holding it back from starting- the shutoff tap ie tube joints leaking?
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    Re: NH 8340 weird dash and won't start

    It would seem unlikely but perhaps more than one fault. I has a problem with the diesel feed pipe where it crossed the transmission under the front end of the cab.
    It had chafed but did not really drop diesel. It did let in air. Before it would not run at all it was surging.

  10. #10
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    Re: NH 8340 weird dash and won't start

    Well I figured out the no start issue, there's junk in the fuel tank. wouldn't start today so I took off the line to the sediment bowl and not a drop was coming out, blew it back and fuel came pouring back. so I'll have to clean the tanks when I get a chance.

    so while I'm on here, couple other little issues with the tractor I think I'll ask about if they're common issues.

    the speedometer still reads fast, by as much as 10 km/hr on the road. checked and the code thing on the dash is the correct 4018 from what I could research.

    I have a code flashing on the dash, flashes owner manual symbol and no three point hitch with #16 on the right. I don't use the 3 pt but would be nice if that wasn't flashing all the time.

    sometimes the display and light by the shifter doesn't always show/light up. is there position switches for that in the console?

    thanks guys.

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    Re: NH 8340 weird dash and won't start

    Can't just answer about the speedo,unless the tractor doesn't have a radar fitted and therefore the rolling radius of the rear wheel and tyre would need measuring and a different code entered to the display other than 4018 which is the default for radar equipped tractors.
    Code 16 is a fault with the left hand load sensing pin or circuit failure.(that's the pin that goes through the lower link arm at the axle end).Could be corrosion on a plug connector and if you disconnect it you may need to recalibrate the linkage.

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