Honda Engine Diagnostics
I'm a big advocate of utilizing the tools you have for logical diagnostics. As an Instructor and administrator at …, I am obviously commited to providing students with a fundamental approach to diagnostics.
In this video I worked with Diag.net to showcase the power of tools you already have to confirm engine mechanical integrity on Honda and Acura vehicles, and really any vehicle that you might have come into your service bay. While to some this might seem low-tech, keep in mind that I didn't have to do any invasive testing and / or removal of parts to collect the data that I needed.
Knowing Honda engines and the pitfalls many technicians fall into I wanted to stress the importance of making sure the mechanical health of the engine is confirmed before getting lost in the weeds.
I hope you enjoy the video and I look forward to a good discussion on this topic. I know there are some out there who can build on this thread and share ideas as to their approach (paging Brandon Steckler).
GREAT POST, Dave. I always had my students drive a vehicle on the street or on the dyno, then go back and watch corresponding PID's. I made sure they studied the PID's Key on / Engine off first though so they could see the MAP "hg" reading ( barometric ). I can't begin to tell you how many techs I've heard when they see a reading of 10" hg, they think the enging is running on very low engine
Dave, Thanks for posting. I’m glad to see how you display, just how easy this info is , to both acquire and analyze. It makes quick work of this diagnosis. I like more that the data is applicable to almost all applications and can be acquired on the OBD2 GENERIC side of the scan tool. This info helps the technician make the connection between engine-mechanical and it’s effects on manifold
Brandon, Glad to see you write in! When I did this video it reminded me of the material in your Worldpac Honda Engine course where you take this a step further with the vacuum transducer. We were just scratching the surface here but my hope is that it creates good dialogue.
Dave, It’s my pleasure! I know, my career change for the better, when I could make the connection between what was happening mechanically, with the engine and with what the scan tool data PIDs were showing me . Like you, my hope also is that a dialogue begins and some lightbulbs start turning on for those who are in a similar position as I was sometime ago.
Hi Dave, It was great working with you during these video shoots. I’ve seen the in-depth footage from your VTEC video and I hear that will be available for posting soon. FYI, we’re currently testing video embeds and we should have that feature into production in time for your next post.
I have a dumb question about this video. describe a tight valve? when I think of valves needing an adjustment I think of them gaining clearance between the top of the valve and the rocker arm. which I would not say is tight but loose.
Hi Nathan, valves can recede into the head and cause a lack of clearance between the stem and the rocker. The significance of this occuring is an increase in valve-duration (which increases overlap) . It can effect idle-quality, compression (if it’s the intake valve) and even shift fuel trim outside the threshold for rich/lean DTCs
Thanks, Brandon that makes since. one more question you say " valves can recede.." is that the typical wear we see? Not on the rocker and stem or cam?
Correct, they tend to sink into the head. It’s also typical to see valve clearances increase over time as well, cauing the opposite effect (less overlap).