Testing vacuum advance unit.

[chano]

Thanks, Mike.

Will try again shortly.

Alan

[chano]

Just tried again, this time on gleaming metal. Nice thwacky spark from coil HT lead.
My sparse tool kit doesn't comprise a voltmeter. I'll borrow one later to check voltage as suggested
before ordering Hall sender.


Alan

[Grun]

Just tried again, this time on gleaming metal. Nice thwacky spark from coil HT lead.

Glad you are making progress

Previous reply was from 'toomanytoys' ,....... not me I have been digging the garden!

Mike

[chano]

Thanks, Toomanytoys.

Happy digging, Mike.


Regards

Alan (digging deep into his shallow font of mechanical knowledge)

[bigherb]

Alan,
I have a couple of manuals which cover electronic / fuel injection systems, as it is rather new technology to me, (an old duffer).

According to what I have read, the Hall sender is a silicon chip through which is passed a small current from one edge to the opposite edge.
When a magnetic field passes through the major axis, (i.e. the face) of the chip, a (tiny) voltage is created across the other two edges.

(Think of it as a thin square) Current from left edge to right, voltage appears from top to bottom edge when magnetic field goes through the thin face.

The thing is that the sender needs a current feed and an earth return to provide its voltage output. So a perfectly serviceable hall sender will not work without the feed (and earth return) circuit.

This is what I believe 'bigherb' refers to when he says.......

before you replace the sensor check there is more than 5 volt across the two outside pins of the three pin plug.

I tend to stick to the old adage....... 'If it ain't broke..........' so having had (as yet) no problems with the distributor and associated gizmos, I can only tell you what the books say. They tend to be generalist, but feel free to ask and I will do my best to find what I can from them.

Mike

You are quite correct, the Hall chip recieves it's supply and earth through the ignition amplifier or the ECU in the case of the MV engine. It's just a check to make sure the amplifier has a path through it and there are no broken wires.

[Grun]

Cheers bigherb,
I am trying to read from three different Haynes manuals, and really do not want to go disconnecting circuits on my own DJ and sticking a multimeter across various terminals to check readings.
You obviously have had hands on experience with the beasty, so much easier to advise in that case.
Thanks
Mike