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Thread: Discovery with Problems - results

  1. #1
    mjsab Guest

    Discovery with Problems - results

    Firstly thanks to all for the welcome and advice. Each suggestion was explored........

    I took it Monaro Offroad and had the guys check it over, good news it ain't the fuel pump, cause they changed it ( and charged for it) ouch!

    Bad news in their own words "its got gremlins"!.....Don't know what it is still but what happens is the coil gets no charge, in fact it gets no charge then every once in a while it does then it doesn't so what ever its electrical.

    Cure to get started( rather than flatten your battery) or in emergency = run a wire from the battery to the coil and away see goes?...........to stop remove wire ...

    Anyone got anymore info............ECU was mentioned what are the symtonms of a ECU fault, what is the ECU, I gather its the computer brain chip, sounds expensive?

    Anyway an auto electrician has been summons, hopefully its a dud wire!

    Mick S

  2. #2
    Moses Guest
    By running a wire from the battery directly to the coil, you are bypassing the ignition switch and a few connectors. I'd be looking in that part of the loom. Does the coil have an external current limiting resistor (ballast resistor - a white ceramic thing attached to outside of the coil with a wire going from one end directly to a coil terminal)? If so, it could be playing up. Try shorting it out without running a lead from the battery to the coil. Ballast resistors usually go open circuit, full stop. On very rare occasions, wire wound ones can develop an intermittent connection due to fatigue in the wire within the resistor.

    Also, intermittent charge into the coil can be caused by a worn distributor bushing. This causes the distributor shaft to wobble about, seriously altering the dwell angle of the points - they stay shut. If you have electronic ignition then this is not a cause for concern.

    But if everything is fine by running a direct wire from battery to coil, then the distributor is not your problem and it gets back to the ignition switch, and associated circuits.

    I didn't see your previous posts. What motor do you have?

  3. #3
    mjsab Guest
    Thanks Moses,

    She's a 1996 Discovery V8 i 3.9Litre ( 147,000km)

    The ignition switch was was pulled down and checked to be okay, Rod ( mechanic) mentioned he checked the dissy, but not sure if he checked the bushes etc, does my model have electronic ignition?...I'll have a look. I asked him about the coil end he seemed to think the coil was okay.....

  4. #4
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    Doesnt having electronic ignition elminate the need for a distributor? Or am i confused, if this is the case your model doesnt have electronic ignition mjsab. Am i right or wrong, all my cars have had distributors, then a V6 Commodore (obviously no dissy) now the TDi, mind my knowledge of mechanics is good, but auto electrics is nil, can anyone confirm? Matt
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  5. #5
    disco95 Guest
    You still have a distributer with electronic ignition. It just works a little different. I don't think it has a rotor inside.

  6. #6
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    Its all flooding back now disco, i knew something was absent with an electronic ignition, there is still a dissy, buy no points or rotor, now i remember, thanks Disco. So mjsab, if your has a rotor button and points it doesnt have an electroinc ignition. I think thats right, anyone confirm or correct my claim? Matt
    <a href=https://the4wdzone.com.au/wp-content/uploads/logo.png target=_blank>https://the4wdzone.com.au/wp-content/uploads/logo.png</a>
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  7. #7
    Join Date
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    all discoveries came with electronic ignition.
    points ignition was no longer used when the discovery was produced


    i had a problem once wher i checked everything and all was ok
    car wouldnt run.
    found out the coil would only work in the upright position but not while lying on its side. very wierd.

    your problem sounds a lot like an ignition module or bad connection
    it is quite possible to be the alternator as it is always ignored because it
    is working and keeping the battery charged. it might be spiking the ecu
    and causing all sorts of faults.

    sugestion: start the engine and carefully wiggle the wires from the dizzy
    and the coil and the the main harness from the computer and any other
    related wires to ignition system and associated sensors e.g. coolant temp
    i am assuming plugs and leads have been checked and are all serviceable.


    if a fault cannot be found anywhere the only way to find it now is by substituting known good parts for any suspect parts. you will need a good friend with identical vehicle to <span style="color:red"> lend </span> you parts of his.

    trial and error. when you find the problem part you only buy that.

    how did you come to the conclusion the spark is cutting out?

  8. #8
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    If the car fails when hot it most likly the ignition amplifier module. Also you will find a fusable link in the loom (taped in) just up from the battery this often getts corroded. Next if it has the factory ignition issolator fitted these are also very prone to cause the same type of fault. Won't be the ECU.

  9. #9
    Rovernaut Guest
    I also had that starting gremlin 0n my '96 Disco. I untaped the ignition wires and found there were 2 inline connectors. They were wet with mud and crud. I cleaned the connection contacts and also all connections around the ignition amplifier and all seems ok now. It was a re occuuring problem that hit when least expected. Hot or Cold.

  10. #10
    Moses Guest
    Originally posted by Ace
    Doesnt having electronic ignition elminate the need for a distributor? Or am i confused, if this is the case your model doesnt have electronic ignition mjsab. Am i right or wrong, all my cars have had distributors, then a V6 Commodore (obviously no dissy) now the TDi, mind my knowledge of mechanics is good, but auto electrics is nil, can anyone confirm? Matt
    Early ignition systems used a cam on the distributor shaft to open and close a set of contacts inside the distributor. A condensor (capacitor) across the points was installed to reduce the sparking of the contacts and extend their life. This is known as the "Kettering" system. With the advent of better technology, the contact points and condensor were replaced with a "hall effect" device and the shaft of the rotor now had a "star" instead of a cam with the same number of points as there are cylinders in the engine. A rotor was still used to distribute the spark to the plugs. Hall effect devices work on a magnetic principle and the flux state changed when a point of the star would pass the hall effect sensor.

    Contact systems may still be used on mowers and the like, but even those are going electronic.

    Electronic ignitions without a distributor employ a crankshaft position sensor and this information is fed to the ECU computer and all the smarts inside the ECU figure out what cylinder to fire when.

    As far as diesels are concerned, they don't have SPARK plugs, only GLOW plugs to preheat the cylinders so the diesel fuel mixture can ignite under very high compression. Hence, you'll never find a distributor on a diesel.

    Capacitor discharge ignition (CDI) and Transistor Assisted Ignition (TAI) did away with the coil and was the start of true electronic ignition systems.


    Hereth endeth a basic lesson in ignition systems! 8)

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