2015 Ford Transit Van - Misfire Case Study Video
Here is a case study I have just completed covering misfire analysis. I hope this helps.
Fantastic Bernie! Love my ATS 4 Channel. Can't wait to try using the output more. Keep the video's coming. RR
Thats a great way of testing... my only question is couldnt the load be coming from a pcm supplied ground or signal that was shorted in the harness? And when the pcm is disconnected the short/load would not show as the signal was coming from the pcm to begin with through the shorted path in the harness?? Maybe im over thinking it.
No you are not over thinking this. The wiring could become shorted within the harness. Once the harness connector is removed from the ECM, take one of the scope channels and test each pin at the harness. Only one pin should have a frequency on it. If any other pin (wire) has a frequency on it they are shorted together.
Thank you bernie. I appreciate the follow up!
Elias; Good morning Sir, I hope all is well. Watching both of Bernie's videos where he uses the TTL Circuit of the ATS Scope I had the same question. While diagnosing a 1999 Ford Taurus the vehicle was setting codes for both of the Down Stream Oxygen Sensor Heater Circuits. The circuits were being pulled to ground as soon as the key was turned on (setting Low Voltage Codes). Installing the TTL…
Bernie that is exactly why the ATS Escope 4 Elite is the most intuitive scope out there. The TTL pull down feature is an awesome addition to this scope. Thank you Bernie for all you do for our industry. Great case study. This scope disables the parts cannon!
Thanks Bernie - great case study on COP drivers. Love the extra features in that scope!
How do we know what frequency to set the pulldown signal to?
Jerry When looking for a circuit that maybe loaded, any frequency will work. I usually use 20 to 100 Hz, I use the TTL output for this. The pull down out is to sink current, such as to turn on a fuel injectors or ignition coils.
Thank you very much I wasn't sure if it made any difference.
Another excellent case study showing a logical approach to finding the problem. What are you using to seal the wires after using your piercing probes? I have to admit that I die a little inside every time I see them being used. Up here in the North East that is a recipe for disaster after a year or two when the green fuzzies take over.
Phil I seal all wires with clear Plastic Dip. It comes in a large can and I put it in small containers that I carry . This works well to seal the wire and the clear is not visually noticeable.