Hello Odyclub,
TL;DR: How to diagnose and confirm VCM issues due to cylinder ring issues on rear bank at 175k miles despite new spark plugs from reading old plugs
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We have owned many Odys until this point - an 01 EX we sold with 500k miles still running, an 06 EX-L that got totaled with 450k (but still ran), two 08 EX-Ls currently in the family with over 250k miles each, and a neighbor's 08 LX with 280k that I still help maintain. I have personally performed 6 timing belt/WP replacements, hundreds of oil changes, and countless other maintenance items to various Odys over the years, so you could say I am familiar with these vans. So when I heard my friend was selling his one-owner (mostly) dealer-maintained 2012 Touring Elite, I jumped at the opportunity to buy it! With just 140k miles, based on our previous Ody experience, I figured it was "just broken in".
At first, it was love at first drive. The smoothness, quietness, and refinement over previous gens was night-and-day. We drove it with 5 people, 4 bikes, and a ton of gear from Houston, TX to Angel Fire, NM (1800 mi roundtrip) with no issue and in total comfort, all while returning 22MPG.
From my experience with the 06 and on vans, at some point in our ownership I bought a VCMuzzler II and installed it in this van to prevent potential future VCM issues. Various such other trips later, we had put about 35k miles on it and now sat at around 175k miles. Then the problems began.
My parents drove the van on another long drive and experienced the flashing CEL and codes P0300, P0301, P0302, and P0303. They were able to limp it home for me to diagnose.
My first step was to review the comprehensive maintenance history of the van. I did not find any indication of spark plug replacement in 175k, including with timing belt replacement around 105k when I would have expected it, so that was my first order of business. 6 brand new OE NGK DILZKR7A11G spark plugs later, I was hoping the issue was resolved. Unfortunately, it persisted. The issue seems most pronounced when the van is cold, and gets progressively better as it warms up. The van lacks power, and if you push it beyond very moderate throttle, the CEL flashes with the misfire codes and VSA failure. Once it warms up (after about 10 mins), you can push it fairly hard without the flashing CEL but it still lacks power. As a related aside, the catalytic converters were replaced with aftermarket parts by the PO within months before I bought the van.
Upon further research on this board, I came to know of the VCM issues commonly known for this gen on cylinders 4-6. Most recently, at least 3k miles after they'd been replaced, I took the 6 new spark plugs out to see if the rear bank was oil contaminated - see below. I swapped the front 3 with the rear 3 hoping the issue would at least temporarily be resolved; however the P0300, P0301, P0302, and P0303 came back right away.
At this point, my assumption is it's a VCM issue pertaining to the cylinder rings of the rear bank considering we've had the VCMuzzller II installed the last 2k+ miles, but the 170k plus prior miles, it has not been. The odd thing is, compared to previous Odys we've had which have consumed SUBSTANTIAL oil between oil changes (adding 5+ quarts after an oil change, but only getting 3 quarts out upon draining), this Ody consumes ZERO oil between changes. I fill 5+ quarts and get essentially the same out next oil change.
At this point, we just need the van fixed, and I am about ready to throw in the towel and have it diagnosed at the local stealership. I am still good friends with the original owner, so I figure we'll have the best leverage if he brings it back to the original dealership where he bought it, and if the cylinder rings need replacing, hopefully we can get some goodwill from Honda.
How can I try to diagnose this myself before bringing it to Honda? I am very DIY-oriented so I would like to try that first. I see lots of info on the board about what the issue is, but not much in terms of actually diagnosing/confirming it. Leak down test? Compression test? How does Honda diagnose it before tearing the engine apart?
I took pics of the (possibly) original spark plugs as well as the new ones after 3k in the hopes of learning something from the old school "read the plugs" approach.
I also found this interesting thread that resulted in the dealership initially diagnosing bad injectors on bank 2, but no confirmation from the OP after that: VCM issues - A gameplan
6 new spark plugs after 3k miles, in correct orientation with front of van at TOP of picture, and rear 3 at bottom:
![Gas Electric blue Auto part Metal Fashion accessory]()
Closer view of combustion area:
![Product Automotive tire Household hardware Auto part Engineering]()
Close-up of cylinders 1 or 2 without VCM:
![Fluid Automotive tire Gas Liquid Electric blue]()
Close-up of one of the rear 3 cylinders (I didn't note which):
![Hood Motor vehicle Automotive tire Automotive lighting Gas]()
6 old (possibly original) spark plugs prior to replacement - I lost track of the order in relation to cylinder, so they're in random order:
![Water Liquid Drinkware Fluid Plastic bottle]()
Close-up of the old plugs:
![Tableware Liquid Drinkware Fluid Water]()
TL;DR: How to diagnose and confirm VCM issues due to cylinder ring issues on rear bank at 175k miles despite new spark plugs from reading old plugs
---
We have owned many Odys until this point - an 01 EX we sold with 500k miles still running, an 06 EX-L that got totaled with 450k (but still ran), two 08 EX-Ls currently in the family with over 250k miles each, and a neighbor's 08 LX with 280k that I still help maintain. I have personally performed 6 timing belt/WP replacements, hundreds of oil changes, and countless other maintenance items to various Odys over the years, so you could say I am familiar with these vans. So when I heard my friend was selling his one-owner (mostly) dealer-maintained 2012 Touring Elite, I jumped at the opportunity to buy it! With just 140k miles, based on our previous Ody experience, I figured it was "just broken in".
At first, it was love at first drive. The smoothness, quietness, and refinement over previous gens was night-and-day. We drove it with 5 people, 4 bikes, and a ton of gear from Houston, TX to Angel Fire, NM (1800 mi roundtrip) with no issue and in total comfort, all while returning 22MPG.
From my experience with the 06 and on vans, at some point in our ownership I bought a VCMuzzler II and installed it in this van to prevent potential future VCM issues. Various such other trips later, we had put about 35k miles on it and now sat at around 175k miles. Then the problems began.
My parents drove the van on another long drive and experienced the flashing CEL and codes P0300, P0301, P0302, and P0303. They were able to limp it home for me to diagnose.
My first step was to review the comprehensive maintenance history of the van. I did not find any indication of spark plug replacement in 175k, including with timing belt replacement around 105k when I would have expected it, so that was my first order of business. 6 brand new OE NGK DILZKR7A11G spark plugs later, I was hoping the issue was resolved. Unfortunately, it persisted. The issue seems most pronounced when the van is cold, and gets progressively better as it warms up. The van lacks power, and if you push it beyond very moderate throttle, the CEL flashes with the misfire codes and VSA failure. Once it warms up (after about 10 mins), you can push it fairly hard without the flashing CEL but it still lacks power. As a related aside, the catalytic converters were replaced with aftermarket parts by the PO within months before I bought the van.
Upon further research on this board, I came to know of the VCM issues commonly known for this gen on cylinders 4-6. Most recently, at least 3k miles after they'd been replaced, I took the 6 new spark plugs out to see if the rear bank was oil contaminated - see below. I swapped the front 3 with the rear 3 hoping the issue would at least temporarily be resolved; however the P0300, P0301, P0302, and P0303 came back right away.
At this point, my assumption is it's a VCM issue pertaining to the cylinder rings of the rear bank considering we've had the VCMuzzller II installed the last 2k+ miles, but the 170k plus prior miles, it has not been. The odd thing is, compared to previous Odys we've had which have consumed SUBSTANTIAL oil between oil changes (adding 5+ quarts after an oil change, but only getting 3 quarts out upon draining), this Ody consumes ZERO oil between changes. I fill 5+ quarts and get essentially the same out next oil change.
At this point, we just need the van fixed, and I am about ready to throw in the towel and have it diagnosed at the local stealership. I am still good friends with the original owner, so I figure we'll have the best leverage if he brings it back to the original dealership where he bought it, and if the cylinder rings need replacing, hopefully we can get some goodwill from Honda.
How can I try to diagnose this myself before bringing it to Honda? I am very DIY-oriented so I would like to try that first. I see lots of info on the board about what the issue is, but not much in terms of actually diagnosing/confirming it. Leak down test? Compression test? How does Honda diagnose it before tearing the engine apart?
I took pics of the (possibly) original spark plugs as well as the new ones after 3k in the hopes of learning something from the old school "read the plugs" approach.
I also found this interesting thread that resulted in the dealership initially diagnosing bad injectors on bank 2, but no confirmation from the OP after that: VCM issues - A gameplan
6 new spark plugs after 3k miles, in correct orientation with front of van at TOP of picture, and rear 3 at bottom:
Closer view of combustion area:
Close-up of cylinders 1 or 2 without VCM:
Close-up of one of the rear 3 cylinders (I didn't note which):
6 old (possibly original) spark plugs prior to replacement - I lost track of the order in relation to cylinder, so they're in random order:
Close-up of the old plugs:
