Hi all, a long shot, but I'm after an image from a scope for the input of a coil pack, long shot but thought some one might have one. My scope is not producing what I expect to see. I expect to see a 12 volt square wave at low frequency. thanks
Try this....... Connect the ground clip to the positive 12V and then connect the tip of the probe to the coil pack connector going to the ECU. This is because the ECU grounds the coil pack. I guess that you connected the ground clip to the metal part of the car and the probe tip to the coilpack wire going to the ECU. MichaelZ
thanks michaelz, but I am positive I have wired it correctly. I used a wiring harness extension plug adapter thingy (bought in group buy which conveniently had leds wired into the correct wires) between the coil pack and wiring harness.
Coils have constant 14.4v from coil relay and get earthed via the ptu on front of engine. Ptu gets trigger via the ignition triggers from ecu. These are earths not positive signal. Hope that helps you setup the scope better
thanks for that, i must admit I had assumed I was getting a voltage of 12. I'll try the scope again tonight, maybe I'll open the garage door this time so I can keep a clearer head
Yep, what you will see on the coil negative side is 12v all the time with some back EMF "spikes" when the coil fires, because regardless of what the ECU and PTU are doing ,12v is always present on the coil as far back as the output of the PTU. You should see a 0-5-0v square wave of (circa) 3 Ms on the front end of the PTU which is the ptu trigger input from the engine ECU. The coil is charged for <>3Ms and the coil dischagres on the falling edge of the waveform. E
