|
First, find or buy your insulated spark plug wire puller tool. I know you are going to pull plug wires one at a time at the distributor cap to find which one is problem when you see signal you don't like.
Now make the capacitor divider. Use short thin wall brass tube to slide in high voltage center on ignition coil. Widen if necessary to slide high voltage line to distributor center in top end of brass tube. Next, wrap insulating material like fiber sleeving or good fiberglass insulation around brass tube, remember this is 30,000+ high voltage area, and one or two turns on top of insulation of wire going to vertical input on oscilloscope.
On the 2 nf capacitor, the higher the voltage range on this the better. Adjust insulation material or wire turns to oscilloscope to get readable signal. Waveforms follow engine firing order.
With engine running smooth about 1000 rpm, adjust horizontal scope sweep to show each cylinder on engine 4,6,8, ect. This view is called a PARADE. Check how uniform firing is. Change horizonal scope sweep to display one plug firing. Each plug fires on top of other plugs and this view is called SUPERIMPOSED. Check how uniform the firing is.
Are waveforms upside down? Professional automotive diagnostic scopes have inverter that displays signals going upward.
A good automotive electronic diagnostic manual may have other tests you can perform.
|
