What is the best way to tell if all 8 cylinders are firing, short of pulling each plug wire, sticking a screwdriver in it, and watching for a spark from the screwdriver to the ground of the engine? Is there anything you can buy that clips on to the spark plug wire and will measure current as each plug fires? Thanks Phil

 

who taught you that technque? I like it!

yeah they sell a Probe(test light) specifically to check spark in each wire. It doesn't check your plugs though. I got mine at autozone

 

Yes,

it's an osciloscope, but even the hand held ones are very expensive. For less than $100.00 you can go to a local auto repair shop and have them throw it on the scope for you. The read out tell's you exactly what is going on, even as far as fuel ratio is concerned. They can also electronically shut down spark to each cylinder in the firing order, to give a close estimate of power balance between the cylinders.
Well worth the money in my opinion. You want to make sure the shop knows how to read a scope pattern for a points type system.

 

A good firing spark plug should be lightly coated with greyish brown deposits. If heavy deposits are present, if the spark plug is black or if the electrode or core nose are damaged, the plug needs to be replaced. So, the bottom line, unless you want to stand in a bucket of water and hold the plug wire with the engine running, looking at the plug itself is the best way to see if it is firing. Now, this is assuming you have good wires to each plug. You can test the resistance of each wire with an ohm meter, but you will need to know what resistance you are looking for. Most of us just replace all the wires to make sure they are all working properly.

 

I replaced the dist. cap, plug wires and all 8 plugs. Cyl. 1 plug is black and does not appear to be firing. At home I know that I can pull each plug and watch them fire, that is just such a pain in the a$$. I went and bought a probe type at autozone like was suggested, but seems to be picking up from other wires. I have adjusted the sensitivity, and seperated the wires as best that I can, but I am still suspect if I am getting a good reading with it. It looks like I may have to take it into a shop, or pull each plug individually (very time consuming). I just hate to rely on a shop. thanks

 

If you have headers you can start her up and touch each header, the cold one is not firing. Or if you prefer to not burn ur hand you can take a spray bottle of water and spray.... the hot ones will evaporate right away.