Testing coils on a coil over plug system?

[art leong]

Originally Posted by buzzinhalfdozen

Art, yes hook up your meter and check the resistance, then switch meter to AC volts and crank the engine, you should see Approx. 1 volt AC give or take it depends on the cranking speed the faster it turns the higher the voltage. You said you moved some wires around... anything near the crank sensor or it's wiring? As I said these type sensors are quite sensitive to interference. By the way is this sensor shielded? Also as Ed stated there's no real replacement for proper diagnsis, I realize not everyone has a scope on hand... however by simply replacing a part you could be missing many things, poor connections broken wires ect. that's why that strategy sometimes back fires on people. We see alot of vehicles from other shops that have had large amounts of parts hung only to find simple wiring issues as the source of the problem. We have alot of customers balk at our charge to diag. their veh. however with a proper diagnosis a sucessful repair is almost guaranteed.

Back to square one.
I checked the coils they are all able to jump the gap at 40K the spark doesn't look very healthy to me but I don't have anything to compare it with.
I checked the voltage across the crank pickup and on my volt meter set on ac I get .4 volts with the starter turning the motor. I have a 20 tooth wheel on the crank. I triple checked the timing, Put a new cam position sensor on.
And I still have the problem