Bad ignition module?

[ngnowner]

Hello, the info on this board is great, just wished I would have done some reading here before I bought the car No sense crying over spilt milk now though....but if anyone is buying a GN in brooklyn, I can tell you who not to buy from (the guy has 3 more). Anyway working through some issues, and wanted to see if anyone could confirm. "spring cleaning" complete (filters, fluids, plugs, wires, etc.). I replaced the coil, because one of the towers had full resistance (1-4), the backfire under load went away and the car pulls hard @WOT with 13lbs boost. Has a miss at idle and crusing, no backfire, put it in gear while cold and it stalls. I don't have and can't afford module/coil tester so I put an inductive timing light on each wire. Here's what I see at idle - 1,3,5 appear to be firing normal, 2,4,6 are firing at least double the rate of 1-3-5 and not consistently, a definite "break" (miss ?) in the rythm. Plugs look fine, no fowling. Bad ingnition module???? Or what else might be possible, TPS is set correctly, by the way. Thanks.

 

[ngnowner]

Noboby has a clue huh??

 

[87granny]

When i got mine it did not run when i got it started i found out that two of the towers had no spark i got the coil same thing no spark when i took the coil back off found the material in the moduel was all funkey and gooey replace the moduel and was good to go. I wish i was closer i would lend you mine and see if it helps. You may want to go to the MAGNA section on turbobuicks.com and post the same question mabe some close can help

 

[bmackinnon]

I'm leaning towards a module, but then again, I'm no expert. Remember that these ignition systems are 'waste spark', such that when 1 cyl fires, so does the other cyl. on that coil. Thus an inductive timing light will indicate erratic firing as the wire it's hooked to fires once at the proper time and also once when the opposite cyl. (on the coil) fires. I know I'm not verballizing this very well, but get the picture??? 3 coils in the 'pack', both terminals fire when one does on each coil... SO... actually seems wierd some cyl's look normal.... follow? I'm sure someone else will chime in here??

 

[ngnowner]

thanks Brian, You explained it very well.....so the firing rate expressed by the timing light essentially doubles for each cylinder. I'm not sure then which side is firing incorrectly then. But the firing rate is definetly different on each side with 2-4-6 being much faster with random pauses in the firing rythm. The "glue" is in tact in the module but has a few cracks in it. thanks for the response. paul