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, Wed, 2 Jun 2010 10:20:32
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Dan,
according to Bentley all the diagrams are the same for NON-EZK 1988+ turbos. I'd like to have a look at your wires before going on with advices. Can you post some photos?
But to be honest, it's not a big deal to swap a dizzy with hall sensor of one design with another. Or the ignition amplifier. It's a pretty simple system, you know:
- hall sensor is a logical element that gives a square output (in other words, the output signal is either ON of OFF). There're different types of those sensors, some are 12V, some are 5V (can't say for sure which one is used in C900). So the sensor needs 3 wires: + (power supply), - (ground) and the output. Hall sensor works with apperture wheel that is driven by camshaft (actually, it can be driven by crankshaft, but nevertheless) an it's on-off signals refer to specific CRANKSHAFT positions. There can be vaccum- and rotary-advance schemes, but in this picture to learn how it works in electrical terms, we don't need'em.
- the ignition amplifier. Dude, actually, it's not an amplifier, it's a driver. It takes the output of the hall sensor and triggers (drives) the ignition coil. It can also supply the tachometer with separate signal needed, though most of tachometers can work with the signal that goes from ign amp to the coil. Why we do need this driver to drive the coil? Because the hall sensor is low-current device and the coil works with bigger currents. Also the timing... not that ignition timing, but the timing... Ok, let's put it this way: take it on trust that duty-cycle (*) for ignition coil must be different for different RPMs. That's the main idea why we do need that driver (or ignition amplifier in common terms).
(*) duty-cycle: can be measured in different ways, the easiest to understand is going to per cents. Take a switch. And start toggling in off and on every half of second. Tick-tick, tick-tick... You're toggling it with 1Hz frequency (the full time for the cycle is one second). If the amount of time for each cycle when the switch is off and when it's on is the same, then we have 50% duty-cycle. If the switch is off for every 0.1 sec and on for another 0.9 sec, then we have 90% d/c. If the switch is off for every 0.35 sec and on for the rest (0.65 sec) then we have 65% d/c. If the switch is off all the time, we've got 0% duty cycle and if it's on all the time then d/c is 100%.
Back to those gizmo's. We stopped at the ignition driver or the ignition amplifier. So what wires does it need? Let's count:
- supply
- ground
- input (that comes from hall sensor output)
- output (that goes to ignition coil)
(can be considered as add-on: output for tachometer and such)
So... Oh, forgot to say - in most designs it's the amplifier/driver that supplies hall sensor with positive and ground connections.
Step away: generally speaking one can use any ignition amplifier to replace his own if:
- it has the proper voltage for hall sensor (remember 5V and 12V?)
- it meats the current requirements of the ignition coils (see above re duty cycling + different coils must have different driving timing, since they store the electrical energy and with wrong timing they either blow out or kill the driver-amplifier)
I can bet $50 that say Ari (who I haven't seen here for a long, anyone got any news from him??) or Simon (who appears to know pretty much about everything) can do all the tricks and it takes them not more then twice the time you spent on reading this moonspeak. Just come back with photos of your wiring (for both the sensor and from ignition amp connector) and ignition amp (I'd like to read it's label to check it's ID#) and you should be good pretty soon. You may only need a DC-meter (and maybe some needles).
Zig
posted by 77.37.1...
, Wed, 2 Jun 2010 10:20:32
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