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Ian Perry

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Hi all,

Grateful for thoughts opinions and suggestions... Just spent a few hours (warm-up for the rugby!) trying to fault-find on a 1500 Spitfire that won't start/run. I've posted this in the general technical section as the problem may be a hybrid of several problems some generic some more specific...

Sorry this is a bit long-winded!

Starting set-up. Owner bought it with a bodgey looking installation of a contactless electronic distributor (I assume Hall Effect (HE)). According to the Repair Operations Manual, the car as original* has a ballast resistor wire and 6V coil; however it now has an aftermarket coil of unknown parentage. Overall mixed condition with evidence of bodged maintenance/"restoration"

* difficult to gauge age as it has a personalised plate and owner has lost the V5 (temporarily I hope). Commission number is FH104631

Investigation to-date. Put simply, it was running and now isn't. The engine turns over, and there is live 12V to the coil, but according to my timing light there's no HT spark.

The normal set-up at the coil would be - positive side - a white/pink (ign switched ballast resistor wire delivering constant 6V) and white/yellow (temporary feed delivering 12V while starting). Negative side should have the white/slate feed to the rev-counter, and with a normal distributor the black "signal" from the points.

However, in reality...

On the coil +side is an ignition-switched 12V BROWN feed, and what looks like the OTHER end of the white/yellow (which should actually have been on the solenoid). The combined female connector that has the white/pink and white/yellow, that should plug onto the coil, is floating in mid-air. So the only source to that connector appears to be the ignition switch via the white/pink, but the voltage is 12V not the 6V you'd expect from the ballast resistor.

The HE sensor in the distributor has red and black wires connected across the coil, but not having anything to go on I am struggling to know how it SHOULD be connected (it was disconnected and reconnected in a hurry as part of another problem, might have been reversed then). I assume the HE sensor needs constant 12V supply (red?) and sends a 'chopped' earth to the coil (black?) to energise/de-energise it - but if it is wired wrong way round, will that have damaged it? 

So my initial diagnosis for non-running is the HE sensor. Two options are to fit a spare standard distributor to test that theory, though I might just try a test lamp instead of the coil, should see it flashing if the HE sensor is working?

But separately the wiring is a worry. The brown wire to the coil - ign switched 12V, but brown? That normally signifies constant 12V. The ballast wire seems to be delivering 12V. And there's also a green/brown wire coming off the solenoid that I can't account for.

The Gods alone know what else is connected/not connected... I'm now wondering where I can safely put the multi-meter test probes!

Any comments, anyone? VMTIA

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