Thread: Ignition troubleshooting - Help

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Guys,
I thought I had this one licked the other night when I switched plugs, but I think I treated the symptom and not the cause. Can someone please tell me a quick way to tell whether a coil is firing? I know, sounds stupid, but I have an MSD coil-per-cylinder setup on my BBC. Cylinders 2,4,6,8 are firing away when I hook up a timing light on each of them. Cylinders 1,3,5,7 are not firing or fire very sporadic. I'm checking with a timing light on each wire - will that give me a true reading on whether the coil is firing regardless of the plug's status (good, fouled, etc.)? Come to think of it, I think I'll unplug a wire from the plug on the passenger side and test my question while I wait for some of the gurus to chime in...

I'm tracing ground wires to the coils and everything I can think of, but I'm having this nightmare that it is an MSD ignition problem and this is an expensive setup...

Thanks all...

Answered one of my own questions guys. I unplugged the plug wire from the "good" side (cylinders 1,3,5,7), put a timing light on it and started the car. The light still flashed every time the coil fired. Bad news is that tells me that coils over the 2,4,6, and 8 cylinders aren't firing regularly.

How do you go about troubleshooting one of the MSD ignition systems at that point? I'll cover the basics of power, ground, etc. but beyond that I'm at a loss...

One more time to clarify: should an unplugged spark plug wire still show as firing every cycle when a timing light is put on it?

Yes ,just like the other side fired when unplugged ,bad coils ...possible ground or under voltage or over voltage ,bad connection ...etc.
These are some or the harder things to track down ....just eleiminate the possibilities one at a time ,try the grounds and the power wires first to see if they are actually bad or its just a wire problem,then goto some new coils ,that way if it is a wire that caused it ,it will not happen again or it maybe just a wire issue....?
{EDIT}
Also the MSD site has some good info for trouble shooting.

all one bank how big of gap are the plugs at ? try gapping the plugs all at 035 and buy four new plugs or a full set look at the heat range if this car had a blower and was race it has to cold of plugs in it for the street

As always, I appreciate the help guys...