crushingday

A friend is trying to figure whats up with his 79 euro. He says "Replaced module with a used one and it is still shorting coil to ground. Meaning. Coil looses power with key on because module is grounding negative side of coil. Even with distributor disconnected.
I am sorry i do not have any more info on his diagnostics at this point, but even with the preceeding , and possibly incomplete info, Can anyone help?

drooman

The ignition modules rarely fail. the module is supposed to ground the coil intermittently with engine running/turning. if he's trying to find a no-spark...green wire is first stop

dr bob

The module does in fact ground one side of the coil in normal operation. The "trigger" from the Hall sensor in the distributor, via the Green Wire, tells the module to OPEN the connection to ground. It's when that connection OPENS that the magnetic field in the coil collapses and generates the secondary voltage needed to make a spark.

Diagnosis starts at the distributor (make sure the sensor is intact, the "reluctor" is actually spinning), and moves quickly to the Green Wire. The connectors at the distributor end are particularly fragile after some aging and heat exposure. The actual signal from the little sensor is very high impedance, and subject to noise and poor connection problems. The wire itself is a "twin-ax" construction with a shield, hence the three pins connecting at each end. Should any of the connections be less than perfect, spark becomes erratic or non-existent. As others suggest, the Green Wire is the most common failure point. You can test for continuity in each conductor and for shorts between conductors using a multi-meter. If the connectors are at all crumbly or the wire sheath is cracked or even just crispy, a whole new Green Wire is in order.

crushingday

Thanks Dr Bob and Drooman!