Using Alternator Voltage to ID a misfire
A short demo of using alternator voltage to ID a misfire. The computer effectively picked out misfire number 3. Misfire was repeatable and consistent. I hooked up for demo purposes. Truck is a 2007, but did not see VIN M listed as an option in the drop down for that year.
Bill, This looks interesting but can you add a little more detail. When you say the "computer" picked out cyl3 do you mean the Picoscope or your scanner? In the file I see a drop in the ripple voltage near the cyl 1 trigger. How does this correlate to the cyl3 misfire?
I apologize Bob, By computer I should have said the misfire monitor on the scan tool. Basically I am looking for a consistently low upswing in the delta voltage on a specific cylinder. I can I.D. number 1 to start by looking for the first start of upswing in voltage after the ignition fires. There is a latency in the voltage pattern that needs to be accounted for. It is a quick and dirty test…
Thanks, I get it now. Have you done this on other vehicles? It certainly looks like a nice quick and easy test if it's repeatable.
It is super easy, and super fast. It usually works, but there are times that it looks like gibberish.
Hmm. I wonder if you have just discovered the computer algorithm for Ford's (IDS) Power Balance test. :-)
I think IDS uses the crank signal frequency, but this is quicker. Especially if you need to try and find wires (not using ids)
nothing quick about setting up a scope out here, I have to keep it packed away or it gets covered with dirt from the wind across the baron fields above us.
I bet. Maybe a little cart with a cover?
The floor plan of this place has everybody constantly passing through each others' work space, so it's safer locked away. Super-cool method though.
Is there a concern of someone stealing if it was left out? It is a cool method.
Spencer, More of concern of knocked over and broken then stolen. Commercial space costs more than residential in Hawaii, so we don't have much room in the shop.
I see. One thing I am blessed with is a lot of space. Previous shop was a bit tight so I kinda know where you are coming from. We have pleanty of scopes and they are used on a daily basics so they are out in the open most times.
That's cool. The only shop-owned scope is the old MODIS. Nobody uses that. The rest of the scopes are mine, and they are all stored away. I kept wanting a better one, from watching all the videos five or six years ago, but after finally getting a PICO, I think I have used it ten times in two years. Most times it doesn't help, (it just shows nothing wrong), and the customer will never pay for…