GTV6 Ignition module

[sportiva]

I was here

[Rising Sun]

Happy to have a look tonight after work. Stay tuned...

[Rising Sun]

Ok, I've put a little diagram together for you. Note that the wire colours are when looking at the back of the plug (the wire side, not the terminal side). I hope this helps

[Rising Sun]

No stress at all. Happy to help!

[carlo rossi]

not sure if its relevant but if you have a 75 module from a 4 cyl it will count 6 sparks per rev as opposed to 4
so you end up with a limiter at around 4200rpm

[Colin Edwards]

I had a med < hi rpm miss on my 75 3.0.  Replaced plugs, leads, distributor cap, rotor button and ignition module as well as cleaning up all the grounds and +12V supplies.  Need to be careful with the ignition module as the number of pins is critical.  Must be a like for like replacement.

None of the above really cured the misfire, however replacing the rotor button probably had the greatest impact.  All these needed doing anyway so no harm.

The coil however was non-genuine.  PO had fitted a Bosch GT40 for reasons unknown. The primary resistance of this coil was designed for systems with breakers / points.  After a bit of research managed to locate a Bosch coil with the lower primary resistance suited to electronic ignition.  Mis-fire eliminated!

Coils for breaker-equipped ignitions "usually" feature higher resistance primary coils so as to keep the current lower and prevent point pitting, metal transfer and welding etc.  Coils for electronic ignitions "usually" feature lower resistance.  The ignition module "usually" features on-board current limiting.  If the resultant spark is voltage supply sensitive, maybe the coil primary resistance is a tad high?

[Colin Edwards]

Hi Sportiva,

Given how hostile an environment the engine bay is to anything electrical or made from rubber or plastic, fair chance the coil has seen better days. 
The coil may have shorted primary and / or secondary coil windings.  Either one will significantly reduce the spark power.

I sourced a new coil from one of the club sponsors here in Melbourne.

When parking the 75 in the garage after taking it for a punt, I have a habit of fully lifting the hood.  Prevents the heat soak from cooking delicate, expensive and difficult to replace gear critical to performance and reliability.  Might help.........cant hurt!

Colin.