This 2006 Honda Accord V6 is running ROUGH at 205k miles.
Owner says it’s misfiring at idle, and won’t pass the State Emission Test with a persistent P0300.
Plugs and coils obviously didn’t help.
Although I suspect what the issue is, let’s PROVE it with scientific DATA before quoting the customer on the final repair procedure.
PHAD PRESSURE TRANSDUCER:
http://www.pinehollowdiagnostics.com/phad-pressure-transducer.html
IVAN’S PICO WAVEFORMS:
https://drive.google.com/drive/folders/1-qJemugyDGpooHc1Z8oK0gCOeBNUfeZx?usp=sharing
2023 Upgrade LAUNCH X431 PRO3S+:
https://www.amazon.com/dp/B092894STV?linkCode=ssc&tag=onamzpineholl-20&creativeASIN=B092894STV&asc_item-id=amzn1.ideas.NHZL00NIDEPF&ref_=aip_sf_list_spv_ofs_mixed_d_asin
TESLONG NTS500 Dual Lens Endoscope:
https://www.amazon.com/dp/B07SQ4FLYX?linkCode=ssc&tag=onamzpineholl-20&creativeASIN=B07SQ4FLYX&asc_item-id=amzn1.ideas.BH34H8T28VY4&ref_=aip_sf_list_spv_ofs_mixed_d_asin
VAMPLIERS:
https://www.amazon.com/dp/B00LMOAYR2?linkCode=ssc&tag=onamzpineholl-20&creativeASIN=B00LMOAYR2&asc_item-id=amzn1.ideas.2N7WCA81DLG3L&ref_=aip_sf_list_spv_ofs_mixed_d_asin
Enjoy!
Ivan
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Bad On Plug Ignition coil. Low voltage. Bad battery. Bad alternator. Stuck relay's.
Ivan if the idle was acting up because of carbon build up could you inject some water when hot to clean up the carbon build up? This is just a question I am not suggesting that I think carbon build up is the problem.
Check springs
I would do a top engine clean with an Italian tuneup. You can get the valves rotating when you do the Italian tuneup.
Once you start removing spark plugs you can put the computer aside and do a physical pressure test on each cylinder and also borescope them
I had a 2003 Eclipse with the V6, it ran perfect, every once in a while it would sputter for a couple seconds, pop a PO300 and go back to perfect, never cared to figure it out, but it perplexed me
Ivan, you really need an articulating boroscope. The tip articulates 180 degrees so you can look back at the valves. Also you can use it to look at valve seats with the adjustments. Worth their weight in gold!
if you suspect a burnt or partially seating valve. why not do a leak down test right off the bat. it would give you pass/fail info right away and resolve cylinder combustion/sealing integrity. that's my thought.
You can disable all injectors with scan tool on honda
Your abilities and scope are both impressive….BUT-
If I encounter a 200k mile honda, that has never had a valve adjustment, especially one with random idlespeed misfires, it needs a valve adjustment. Whether it is convenient or not.
As the measured valve clearance approaches zero, the times a valve begins to leak or not depend more and more on the relative temp of the valve-vs-head..exhaust valve length changes with temp..which depends on throttle position…acceleration or deceleration, etc.
If the clearance would measure 0.0005", it is too tight, but will seal during your cranking test. Then leak as soon as the valve heats and lengthens 0.001" and fails to close completely. And will be burning away at this time.
Another factor- I have seen honda fours and v6s with many fewer miles that have very loose valve to guide clearances. Just loose, worn out. This will cause valve to seat contact to be less predictable. Having ample valve clearance matters even more now- if the clearance is almost zero, and the guide can no longer be trusted to center the valve head in the seat, leakage could occur randomly, depending on temperatures, rpm, valve spring vibrations…etc. it just becomes uncertain.
A valve adjustment might save the guy head removal or replacement in the near future, which might send an old, otherwise good car to the junkyard, depending on the owners budget.
That picoscope is so useful and cool, but doesn't replace maintenance that you just have to do. Hondas with screw and locknut type valve adjustment NEED that. Buy something with hydraulic lifters if you don't like that. Or a toyota with shim type adjustment…still needs it, but goes a long long time.
That slight difference in compression could very well be stuck or almost stuck rings, too.
A leakdown (differential) compression test would be interesting, but most car people seem to never do that. It also will not show a valve that barely closes during the test (when cool) but will leak when the exhaust valve is 1100 deg f under a load, when it really matters.
Burn, baby, burn! It'll never seal again.
Just wandering if it was okay to disable the fuel for the compression test?
Just wandering if it was okay to disable the fuel for the compression test?
By cranking with the pedal down you should be activating clear flood mode, so you shouldn’t need to remove the relay, no?
For the fellas who don’t have all the fancy electronic equipment. You can use a piece of paper, hold the edge, let the rest flap against the Tailpipe. A burnt/sticking Valve will suck the paper to the pipe. Then a conventional Compression Test of each Cylinder will tell you the offending Cylinder/Valves.
Great video but just a tip about your egr statement not causing a single cylinder misfire. Thats actually not true as the ford windstars with the 3.8 and really any engine with egr flow to individual cylinders can suffer an egr misfire if all the ports are plugged except for 1. Now egr shouldnt be open at idle right but it can happen. An open egr and a single egr port thats clear can definitely skew an individual cylinders fuel mixture causing the misfire.
Again great video
Measure twice, cut once… Pays off in what you said. "Research and make a game plan… Paying off dividends"
I have chased this same code on my 2001 jeep Cherokee fired parts canon new fuel pump only thing left is an injector only misfire is on cylinder 3 167000 miles on the car it runs great sometimes when I loosen the gas cap to get gas the pressure blowback is really high
Bad injector
In cylinder compression waveform needs to be divided on 720 degree scale to check if valve opening and closing times are different in both banks.
Can’t wait to see part 2! My TL has 230k, valves never adjusted, it has a misfire at idle but no codes. I’m thinking the valves need an adjustment but was going to wait until I do the second timing belt job, did the first one at 140k. I’m doing plugs soon since they have more miles on them than the timing belt.
I just recently did head gaskets on my wife’s 2010 Forester and your video on disassembling the heads was super helpful! That was the first time I’ve adjusted valves and the car runs smoother than ever now.
It was my understanding that tight valves would be an excited employee (open early and close late) and a loose valve would be a bad employee (open late and close early). Therefore, a tight valve would increase valve duration and a loose would decrease valve duration. With such defined valve events, I think you should compare to the known good. What’s your opinion on that?
Also I wrote a program for piston overlays and it’s free on my channel with a demo video. I couldn’t find a free one, so I wrote one myself 2 months ago. I’d be interested in your feedback. I’m not as good at doing it in my head like you lol
Great work. The only thing I would do different, is comparing cylinder 1 to cylinder 5, because 5 has no misfire. A known good.
suspense…..something electrical withh banks off not mechanical.
I would go after timing and make sure that’s on the dot these Honda V6’s only have one cam sensor and it’s on bank 2 timing for bank one is made off of an assumption that it is where it needs to be and cause random miss fire code with no cam crank correlation codes, might also be why bank 1 is showing rich
Two ways to check if it needs a valve adjustment: 1: Brandon Steckler shows using a pulse sensor on the intake looking for the signature “M” indicating valve overlap. 2: Honda map voltage pid for valve adjustment. 0.7v good. Anything above 0.7v is suspect
Electronic throttle body on the 2006 V6.
Also, in 2006 Honda changed an electronic throttle body on the 4 cylinder Accord.
5 hours for valve adjustment is alot.
I use the MAP data on these and it will run a little rich on that bank with the worst valve. The seats wear out just a little and tighten up the lash.
Hondas never break, they only need repairs.
Good video. You like using pico 7 over pico 7?
Great diag! It definitely looks like it needs a valve adjustment. One thing I look for when diagnosing these is to graph MAP sensor data once it's warmed up and you see dropouts if the valves need adjustments. I think that is why it is running rich; since it's a speed-density engine, the main input for fuel is the MAP sensor. Thanks for sharing, looking forward to part 2!