I’m Ben from Switzerland. I Wanted to start my Swiss model 1990 DD6 the other day but wouldn’t fire (never a problem before). Tried several times until I notices smoke appear from under the bonnet…
After closer inspection I notices that the negative lead from the main ignition coil to the amplifier had shorted…w/b cable was severed and insulation melted and burned…
Not being a crack expert in things electrical, could someone give me a tip as to what the problem could be. Grateful for any support.
Why not the coil(s)? After all the amplifier only gives power to the coil primary, no?
Or a short to ground. I‘d first change the wire in question and then check resistance to ground before possibly frying a good module.
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The wire from coil negative goes through the ign amplifier to ground, Mark.
The current flows through the coil while the ign amp is grounded, charging it - the spark occurs at plugs when the amp breaks ground connection. Nominally, the connection is brief (the dwell angle) - and the coil limits the current flow…
Three possible causes for wire burn; the coil is shorted - disconnect coil ‘+’ wires and ohm the between coil neg and pos. You should read around 1 - 2 ohms for a working coil…
Secondly; the wire itself shorted to ground - which may happen due to rubbing. Replacing the wire, as Aristides suggests, should be an adequate cure. However; such grounding will cause high coil current flow, overheating - which may have damaged the coil…
With a replacement wire connected to the ign amplifier; ohm between wire and bround - it should read ‘break’ -‘0’ on a digital multimeter. If so; the ign amp, subject to further tests if the engine doesn’t fire - is likely OK…