07 qr25 burning coils

[chendrix]

Hey guys. I’ve got a 2007 Altima with the qr25 engine. When I bought the car it had a bad miss on cylinder 1 and an intermittent miss on cylinder 3. Where the harness plugs into the coils, the wires were frayed and looked like they had been pulled out of the plugs. So I wired new plugs for both of those cylinders. Cranked the motor and burned up the coil on cylinder 3. Replaced the coil and immediately burned another on the same cylinder. I looked at the wiring and the connectors and nothing seems like it is shorting. I ran an oscilloscope on each plug and cranked the motor over. I expected to see a large spike on that cylinder but the voltage never changed on the signal wire and only dropped on the constant like you would expect. I’m not sure if this is normal or not but cylinders 1 and 3 have a constant voltage around 3.6 on the signal wire, while cylinders 2 and 4 showed no voltage until the fire signal was sent. I attached the reading from each cylinder during cranking.