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Thread: Digifant MK2 wont start

  1. #1
    Moderator rubjonny's Avatar
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    Right in the middle of setting up my idle & CO I turned the engine off to calibrate the CO meter, then after that it wouldn't start. I found that the alternator to starter lead was almost in half so I replaced that and left it overnight.

    Come back in the morning and it turned over a few times, caught, died and now nothing. When I turn the key I get the normal dash lights, but the pump doesn't prime. I can hear the fuel pump relay click and the relay next to it (not sure what it is tho) but no noises from the engine bay or starter. Tried jumping it but get the same symptoms!

    The only thing I can think of is I had to replace the earth cable but found the one I got was shorter than the original, and would only reach to the gearbox mount bracket?
    Edited by: rubjonny
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    Forum Junkie Mike_H's Avatar
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    Give the relay a 'playful tap' and if that doesn't work try hard-wiring the fuel pump.

    As long as you've got a decent earth to the gearbox area I would have thought that should be fine.
    Megasquirt for the win!! Long Johns for the Win-(ter Mechanic!)

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    Moderator rubjonny's Avatar
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    I tried 2 relays with no diff, but assumed it was something else because the starter doesn't turn the engine over or even click. (Should have been more clear on that sorry!)

    I fitted the gearbox earth on Sunday and its been fine ever since, but I'm going to blag anotherone from a mate & try it.

    I've just thought of another thing, I found the chunky red/black wire from the ign switch had been cut then twisted together with a bit of bodge tape round it. I put a crimp on it and its been fine for weeks, if this wire had become disconnected would it cause these symptoms?

    Randomly one time I tried the rev counter went up to 3k and back down again, so possibly theres summat up with the coil?

    Edit: Also was thinking ignition switch, would that give these symptoms?
    Edited by: rubjonny
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    Forum Junkie Mike_H's Avatar
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    Could be the ignition switch has gone, but it's not a problem I've had to deal with, so not 100% sure if your symptoms are consistent with that. Doesn't sound like the coil...don't think that should stop the fuel pump from priming.

    Guess you could try bridging out the ignition switch, if you haven't got a spare. Bit wierd hotwiring your own car though
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    Moderator rubjonny's Avatar
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    Yeah looking at the wiring diagrams I'm 80% sure its eather dodgy earth, knackered red/black cable or fried ignition switch
    Luckily I've already removed the steering column spline adaptor so replacing the switch should be easy

    But now even if I get it fixed my idle/CO is gonna be reet fecked up, which is nice

    Edit: Cheers for the help
    Edited by: rubjonny
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    Don't think I did much, but you're welcome
    Megasquirt for the win!! Long Johns for the Win-(ter Mechanic!)

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    Moderator rubjonny's Avatar
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    Actually yeah your right, so here's your coat, now feck off







    Nah you've given me some stuff to think about and its handy to have someone to discuss probs with, great help cheers
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    your new lead didn't make good enough contact, so for a while the starter got its earth through the ecu, that's now blown tho, which is why you have no earth and no life. sorry to be the bearer of bad news you prob need to get that earth lead sorted properly, and a new ecu and you'll be away. The burnt pcb tracks in the ecu can prob be replaced with wires, depends on your soldering skills TBH......

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    Moderator rubjonny's Avatar
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    Don't think so as it did burst into life a couple of times, and try to turn the engine over after it died the 1st time.

    Plus I'm pretty sure that a blown ECU would cause the pump to run constantly rather than not at all, and the starter should still turn.

    At least thats what I've gathered from reading through other 'blown ECU' threads.
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    As you say it normally causes the injectors to be open constantly with the pump running. You may have been lucky, hope so.......

    Get that earth lead sorted b4 a re-try IMO.

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    Yup gonna blag one from a mate, it was a VW earth lead tho from a 1.3 and bolts to the stock location on the gearbox mount bracket thing. Was thinking of running a wire from the gearbox mount to the other earth lug, that should defo cover it
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    Was either a bad earth or something else intermittant. Cleaned up all the connections and added an extra lead from the original earth stud to the negative lead and it started fine.

    I have a feeling that it was due to a dodgy earth and I might be very lucky in that late ECUs have some kind of thermal fuse which prevents damage to the circuit board.

    Either way its a runner thanks to Tucker
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