No leading spark, coil or igniter?
 

On my 85 gsl, I have excellent trailing spark and no leading spark. Cap, rotor, and wires are all brand new. I have the online FSM as well as a haynes manual that outline testing both coil and igniters, but to be honest I am completely lost with this topic. Is there any way I can switch the coils and see if only the leading plugs fire then, or is there an easy way to check without measuring with an electrical tool? I have a test light, and that is about it. I've seen several threads on no trailing spark, but am having a hard time with this. Can someone point me in the right direction? Thanks, Justin

yes you can switch the coils (they are the same) and watch to see if the leading comes back and trailing dies. also, you could swap the ignitors around and see if the lost spark follows

Be sure to check leading coil + terminal for 12v. If u have no test light or VOM run a jumper from traing + to leading +

I checked the + terminals on both coils, and there is power to both. Tomorrow I will pop off the igniters and switch them around, and that will tell me what's up! So to summarize, if the leading starts sparking and the trailing goes dead- bad ignitor. If the leading fails to spark afer the igniter swap- bad coil. How does that sound guys? Thanks for the help.

best bet is to check the ignitors first. the tach runs off of the trailing ignition, so if that's working, you know the trailing ignitor is good.

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The tach was bouncing as I turned the car over today. I pulled the distributor and used mar3's thread to test both igniters. The leading igniter did not illuminate the test light, so I am on the hunt for a replacement j109. Ebay has them for $33 shipped, is this a good price? I am going to pick up an ohmeter soon and check that both ignition coils are working good as well. Thanks for the help!

post a want to buy ad here on the forum. you can usually get the ignitors a shade cheaper.