Has anyone done any research on using the points to drive a pulse to digital on/off divide by two logic to drive the ECU? Thes trigger points are getting rare and expensive and a modern replacement would be great.
Didn't VW use the points as triggers on one of the FI bugs?
Tom

Trigger points are used on all D-Jet cars - VWs, Benz, Renault, even Cadillacs and others.

Way outta my league here - but Jeff please chime in on this:

123ignition Distributor

Doesn't work with electronic fuel injection according to their ad.
Tom

Mueller had come up with something at one time. Ill ask him what he used. Think they were just some small proximity switches mounted on an adapter plate in the stock location.

I was looking more for an electronic answer to the trigger switches. Maybe an ASIC ( application-sensitive integrated circuit) designed to take the point's pulses from the distributor and convert them to open/close signals to the ECU. Any electrical/electronics engineers here that would know about them?
Tom

Prox switches are electronic.

Yes, proximity switches would be a good way to go, but, they would require some modification to the distributor to install the sensor activation piece. I do think this would be an upgrade, but was looking for a simple electronic device that would be able to use the coil pulses to drive the signals to the ECU for injector firing. Either points or electronic ignition would be OK as pulse actuators.
Tom

The trigger points are just 2 mechanical switches diametrically opposed on either side of the distributor shaft. The switches are triggered based on the rotation of the dizzy shaft, and the trigger switches merely signal the start of the injection cycle, through the ECU, to a pair of injectors. Data from the other engine sensors is processed by the ECU to detemine the duration (end time) of the injection pulse.

Because the injection pulse is directly related to the dizzy position, it is related to valve position and timing, and so is the coil firing cycle. But the coil firing moment is not the same moment in time that the injection pulse begins...so some stagger in the two events would need to be figured out, hopefully with a means of adjustability. See the fuel metering/coil firing diagram from the factory manual below.

That said...I would think an optical or magnetic sensing device(s) could be fabricated to do the same function as the trigger points for anyone so inclined. They are just simple open/closed mechanical switches on three wires sending continuity info to the ECU.

ummm build a crank wheel and use a vr sensor or hall sensor attached to a vr conditioner circuit. the vr sensor will put out ac pulses for every tooth on the wheel then you use the vr conditoner to turn the ac pulse signal into an on-off digital signal.

umm but then you might as well get a megasquirt

Isn't that the limiting factor , the ECU is analog , the switches mechanical, the mentioned devices digital . Maybe I'm wrong. I pondered this same question myself, that there may be another way . The trigger points do wear out eventualy.

Jack

I imagine the points actually create somewhat of a digital signal . Its an on off signal of twelve volts.


This is digital .... the vr sensor would be an ac spike signal but the conditioner would change it into a dc on off signal similar to what the points actually do.