Dead coil pack
Posted: Fri Mar 29, 2019 9:48 pm
Hey everyone!
I am having some issues with a 1994 L400 V6, ignition coil pack #3 is not firing! Power to the coil is ok and the coil has been swapped with a known good coil pack and #3 ignition coil does not fire still. it would appear that the ECU is not sending a signal to the power transistor for ignition coil pack #3. The confusing part is that I have swapped out the power transistor and ECU from a 1996 L400 with no change, each component individually and also together. Wiring resistance is OK at 0.4 ohms, I am getting a constant output of 0.045v from the ECU to ignition coil #3, #1 and #2 get 0.300-0.400v at idle and increases with RPM(approx 0.600v around 2000rpm).
Does anyone know if there is a certain input to the ECU that will override firing one of the coil packs? I thought possibly excessive knock signal shutting down a cylinder but there is only one knock sensor so I am not sure if it would do that. A bad cam or crank sensor would affect all coil packs, throttle position sensor would affect timing which again shouldn't single out one coil pack.
I am having some issues with a 1994 L400 V6, ignition coil pack #3 is not firing! Power to the coil is ok and the coil has been swapped with a known good coil pack and #3 ignition coil does not fire still. it would appear that the ECU is not sending a signal to the power transistor for ignition coil pack #3. The confusing part is that I have swapped out the power transistor and ECU from a 1996 L400 with no change, each component individually and also together. Wiring resistance is OK at 0.4 ohms, I am getting a constant output of 0.045v from the ECU to ignition coil #3, #1 and #2 get 0.300-0.400v at idle and increases with RPM(approx 0.600v around 2000rpm).
Does anyone know if there is a certain input to the ECU that will override firing one of the coil packs? I thought possibly excessive knock signal shutting down a cylinder but there is only one knock sensor so I am not sure if it would do that. A bad cam or crank sensor would affect all coil packs, throttle position sensor would affect timing which again shouldn't single out one coil pack.