Lucas 9EM ignition module.

[ian field]

Since other people have started posting car electronics questions, I thought
I'd strike while the iron is hot so to speak.

Anyone got tech info on the Lucas 9EM ignition module?

Thanks.

 

[PeterD]

Since other people have started posting car electronics questions, I thought
I'd strike while the iron is hot so to speak.

Anyone got tech info on the Lucas 9EM ignition module?

Thanks.

What is it out of, what does it do?

 

[ian field]

What is it out of, what does it do?

It was widely used on British cars, during the 80's IIRC.

Its a transistor assisted ignition, but I don't know whether its points or
reluctor.

A couple turned up in a box of auto spares I aquired and it'd be handy to
figure out how to test them..

 

[Dave Plowman (News)]

It was widely used on British cars, during the 80's IIRC.

Its a transistor assisted ignition, but I don't know whether its points
or reluctor.

A couple turned up in a box of auto spares I aquired and it'd be handy
to figure out how to test them..

I don't think Lucas ever made assisted points systems and all the
electronic ones I know are VR.

I think the unit you refer to was mounted on the distributor, and the most
likely vehicle it was used on in the US the Range Rover. The connections
on the heatsink or mounting plate are to the VR sensor, the other two on
top go to the coil. Some later versions had a three pin connector - the
extra one for a cable shield.

The unit can be reliable but rather depends on how hot it gets. On
vehicles with air con it's likely to have a shorter life.

 

[Dave Plowman (News)]

As with all components manufactured by Lucas, the God of Darkness,
it's purpose is to function for a non-specified length of time and
then fail at the most troublesome moment.

There was much worse than Lucas about - close running for a photo finish
are Wipac, Czeckoslovakian and Italian.

I'm in the UK, and quite the most unreliable 'car' electrics I've ever had
was on a Bedford van - made by Vauxhall, a GM owned company. With Delco
electrics. The Delco distributor broke its drive on several occasions.
Perhaps GM thought a 4 cylinder engine only needed half the effort to
engineer parts for? The starter and alternator both failed too. All in
under 50,000 miles.

 

[Franc Zabkar]

Its a transistor assisted ignition, but I don't know whether its points or
reluctor.

Contact points would need significant DC current to wet them, ie to
stop them from becoming oxidised. Magnetic reluctor inputs, OTOH, may
be AC coupled, ie no DC bias current.

I would hook up a 12V supply and measure the short circuit current out
of the input.

- Franc Zabkar

 

[Peter Hill]

As with all components manufactured by Lucas, the God of Darkness,
it's purpose is to function for a non-specified length of time and
then fail at the most troublesome moment.

Bosch have taken up the challenge.

Igniton unit failure takes out coil as it fails short so overheats
coil. Coil failure takes out igntion amp by short circuit. Which comes
first? They all do that sir.

 

[Dave Plowman (News)]

The following web page has a link to a zip file with information of
troubleshooting and testing the Rover/Honda ignition system. It helped
greatly in repairing my '91 Honda Civic. It ended up needing a new
coil (HT shorted to core). Also make sure the ground screw on the
module is tightened to the distributor housing. My module was made by
NEC.

http://www.gcw.org.uk/rover/igniter.htm

That's not the Lucas 9EM, though. And apparently no more reliable. ;-)