Starion ignition system
There are a couple of dizzy types, so some of this is only specific to the one I have (85 Conquest).
The Starion dizzy is quite similar to the Monties, but the vac advance can has two functions, and the igniter is not in the dizzy in the Starion (it's in the spark box). In this dizzy, the centrif advance moves the rotating part of the sensor (the 4 toothed wheel) against rotation to give advance. The "vac" can moves the stator part (the reluctor, I guess) in both directions. It supplies ignition advance under manifold vacuum, and ignition retard under turbo boost. All these functions are strictly mechanical, as opposed to the electronic advance games we are about to look at.
The starion has a knock or spark box, either a black plastic box or a cad plated metal box about the size of a pack of playing cards. This box contains the igniter, which senses the change of voltage sign as the a/c generator in the dizzy (the star wheel, reluctor, and coil thingy) passes thru zero votage on its way from + to -, and - to +. When the box senses this phase change (I don't know how, it's a "black box", remember?), it interrupts the coil's primary - terminal connection to ground, triggering the magnetic field collapse in the coil, which generates the huge secondary votage of the ignition spark. The knock box also monitors the extremely weak piezoelectric signal from the detonation sensor when a shock wave from a detonating cylinder hits the quartz crystal inside the sensor (the piezpelectric effect is one in which a mineral - a quartz crystal - gives off an electrical current when compressed, as when the shock wave front hits it - or when a mechanical noise of the right intensity hits it, more on this later). This very weak signal (route det sensor wire away from plug wires, or other noisy electrical sources) travels thru a shielded wire to the knock box. when it hits a programmed threshold level, the knock box intervenes in the timing to retard the spark further electronically, seperate from the mechanical advance/retard systems noted above. There is also a failsafe mode, in which the knock box throws in some huge spark retard (12-20 degrees), killing power, when it doens't see any signal fromt the det sensor. Very good contact is necessary to conduct the det sensor signal thru the connectors - both signal and shield wire run thru the connector. A mechanically noisy engine (whacking lifters, slapping pistons, bad idler pulley bearings, spapping b/shaft chains or timing chains, etc.) can trigger the det sensor threshold, killing engine performance even in the absence of detonation, just by retarding the spark. Early model (< 86.5) MAP sensors also incorporated a pressure switch that causes the knock box to kill engine spark when boost goes above 14.5psi. This also kills fuel delivery, because the ecu uses the tach signal from the coil - to time injection and read engine rpms - no spark means no fuel either. It's like slamming into a thick mud pit at full wot acceleration, or a short field landing in a C-130 when the pilot goes to full reverse prop pitch just as the wheels touch. Full tilt WHOA.
Some Starion coils use a ballast resistor to cut coil voltage. The resistor is bypassed in ign. start position to get a stronger spark for cranking. I use an Accel Super Sport coil, about $39 at AutoZone, without a ballast resistor, and have strong spark up to 6k. Some Starion systems have spark fade above 5k.
I run a NO pressure switch on the oil pressure circuit that kills spark below about 25psi by interrupting the coil + wire, with a switched bypass that I've never had to use. This also assures you have at least 25psi of oil pressure before it will fire off, saving some cold start wear. It also assures that if the oil pressure drops while you are negotiating the I285 Grand Prix in Atlanta and not paying attention to the gauges, you won't lunch the engine, which is the primary purpose of the system. Similar to an oil pressure idiot light but it breaks a circuit instead of opening one.
