Timing Issue...

[Billholtzman]

When I started my 1978 Spider yesterday it was only running on two cylinders. The day before it was running on four. When I went to make sure it was only running on two cylinders with my timing light it proved my hypothesis. I hooked my timing light up to one of the wires that was not firing and moved the distributor, then both of the cylinders began to fire. With the distributor in this position the engine runs well, but it is off time. It runs on four cylinders and runs well, not coughing, no backfire. There was an aftermarket electronic ignition system that may be suspect, but I am not sure.
Thanks,
Bill in MD

[zachmac]

What timing are you considering "off"? 78 should be about 10 BTDC static. Also, if timing light is one with variable preset make sure it is set to 0.

BUT, what you describe is NOT a timing issue. You describe NO spark to two cylinders before you shifted the distributor. Off time means spark at the wrong time, not no spark. Look at the pickup wires inside the distributor. Sounds like something is frayed or broken. Something is causing your ignition to work intermittently and "timing" doesn't cause that.