208 GT4 ignition problem

After some years of working with my GT4 I can't get the ignition working. I have the Ignitor installed but no spark on spark plugs. I tried the test from Adrian on Ferrarichat. Thank you Adrian! Front and rear bank looked the same on the bulb test used. I am a little worried about the response on the test bulb at the end of the test when it stops with a much larger spark. Why not the same spark from start to finish?

Any help would be appriciated!
/Peter

 

So you have a Pertronix module single distributor setup? Did it work previously and has now stopped working or is this the first time you have tried to run the car since installing?


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Not sure exactly what test you are doing, but one factor might be that, when the starter motor is actually cranking, the battery voltage is about 10V; whereas, when you stop starter motor cranking, the battery voltage will increase to ~12V (and that event, stopping cranking, seems to correspond to the change in the bulb brightness). Is the light bulb connected to the coil primary circuit? (Your calling it "a much larger spark" has me confused since you also say that you have "no spark".)

 

Yes, Pertronix in one single rear distributor setup with Flame Thrower. I used it for about two years ago but had some doubts about 5-8 bank. 1-4 was kind of ok and stable. Today I tested for sparks looking at 5-8 but realised that 1-4 did not work at all!!? It is like I am hunting for the trouble but always being a bit behind. Being alone in garage I earthed plugs for both banks just to be able to see from inside the car. Then I saw 1-4 without spark,but 5-8 working. How is that even possible since using the bulb test from Adrian..

/Peter
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There was a bad batch of distributor rotors (of the type used on your model) where the spark would arc from the metal tab on the top of distributor rotor (where the carbon brush contacts) thru the plastic to the top of the distributor shaft rather than being "distributed" to the plugs thru the cap -- wouldn't hurt to remove the dist rotors, inspect them (the arcing evidence is only obvious inside the bore of the rotor), and swap them -- just a thought. If you've already switched coils with no change, and are sure that the coil primary current is switching = it has to be something in the dist cap/brush/rotor system.

 

The bulb is blinking with a steady rate until I switch key off and then the bulb is suddenly much stronger. I think your explanation of what happens is correct! Sorry for mixing it up. Bulb is stable but plugs are not.
/Peter

 

Had no idea about the bad distributor rotors. I will check that!
Thanks, Peter