@F-150Torqued
Thanks commenting and sharing your knowledge. As I mentioned, I am an absolute beginner in the OBD world, so I undoubtedly have some misunderstandings.
You are correct—I have been using the term “counts” loosely, I should have been using the term “raw values” or “rate”, which then need to be converted to get misfire %. I will try to be more precise in the future.
The Torque Pro “TEST RESULTS” you recommend was where I started with TP. Unfortunately, the results do not show cylinder specific information for my vehicle….if it did, this thread would not exist. For my vehicle, TP only shows a single Pass/Fail status. [I don’t recall if it showed a value and I don’t have access to my vehicle at the moment—if it did, there would have been only one value, not a value for each cylinder.] It is only a guess, but I suspect your vehicle either supports CAN and/or the Ford pre-defined extended PIDs which came with TP.
FWIW—-I don’t appear to be alone in the quest to obtain misfire information using 0653 for J1850 vehicles. Search for “Ford misfire” in this forum and you will see a screen-full of cries for help on this topic.
To your feedback about “chasing the wrong TID”—here is an article from Motor Magazine, which details how to diagnose Ford misfire situations using TIDS 0651, 0653 (my vehicle), and CAN.
https://www.motor.com/magazinepdfs/072011_09.pdf
Note the statement about the evolution of these TIDs over the years. From my understanding, while some tests in Mode 06 were/are standardized, manufacturers can (and have) implemented their own “non-standardized” YEAR/MAKE/MODEL specific tests. I have been using this document, the FORD OBD document you mention, and other forum postings as my primary information sources.
If my vehicle supported the Mode 06 CAN standard, I would have been looking to watch Monitor IDs A2-AD, CID 80 or 81 which appears to provide updated misfire rate values every 200 revolutions (Page 11 of the Ford OBD manual). Since my vehicle supports J1850, I don’t see a lot of options other than Mode 06, TID 53. If you have any J1850 compliant PIDs that you suggest I try that would provide actual cylinder specific misfire counts or the equivalent of the CAN Mode 06 Monitor IDs A2-AD, CIDs 80 and 81, I would love to hear more. These would likely be Mode 22 (proprietary/non-public) types of commands.
To your comment that you have seen “OBDII PID assignment ‘differences’ between like Ford year models assembled in different plants”—-WOW, that hurts my head. It sounds like detailed PID scanning/analysis is definitely going to be required, or some type of VIN to PID database. FWIW—as mentioned earlier, I have tried using TorqueScan, but am unable to capture/save the complete scan when it finishes, possibly due to a bug—others have reported the same issue in this forum. Based on your insight, I plan to revisit this issue this weekend when I have more time to investigate.
Again, thanks for sharing your knowledge—I appreciate your time in helping me work through this. Feel free to reply with any further corrections and guidance.
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