COP Testing

Hello-

I was watching a Danner video about testing COP coils- heres what I got so far-

1. Take out coil leaving the harness connected
2. Start engine
3. Place test light probe to spark plug hole of coil and look for spark (or use spark tester)
4. If NO spark- determine if the issue is control related
5. Turn off engine
6. Connect amp clamp to ground wire or power feed of affected coil
7. Connect DMM (backprobe) into IGT wire
8. Turn on engine and record current and DC at the ground and IGT wires

My question is- what are the readings supposed to be for the current and DC at the ground and IGT wires?

Thanks.
MrMike

When testing a secondary it is best to give the spark a direct route to ground before starting the engine otherwise you run the risk of doing permanent damage to the insulation, applies even more so to 3 and 4 wire coils where the driver is built into the coil.

Coil current varies generally it peaks at 4 to 10 amps. For example the coil in a Freelander which is plug top and wasted spark maxes out at 10amps.
Where wasted spark is used currents are generally at the high end of this range.
When looking at coil primary current on a scope it is really the shape of the current ramp that is the main interest.

At low RPM (sub 2,000 rpm) Many Fords use a multi strike spark strategy that does some pretty weird things with coil control to created multiple sparks at low RPM first time you see it it can look really weird. At high RPM they switch to conventional switching of the coil.

Greetings Andy-

Thank you for some clarification. I think since I dont have a scope yet, Ill keep it simple and just use my noid lights and Lesle spark tester for now. Hope the weather out there is good. Id love to go back and visit- last time I was there was before Windsor Castle burned. Have a good weekend and thanks again for all your replies.

Mr Mike