Honda Odyssey Forum banner

1 - 20 of 26 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I need help and I am getting frustrated with my 2008 Honda Odyssey's check engine light that is now coming back up every few months. I have changed my Honda Odyssey spark plugs/coils at least 5 times within last 3 years and I think it might be time to take it in. I spent a lot of time trying to figure out what the root cause of this issue is and I can't seemed to pin point it. I do some work on my cars but nothing major like replacing timing belt, rebuild engine, etc. It seems like back 3 spark plugs and coils are going bad within 4-5 months recently. They seemed oily and dirty.

I don't know if anyone else had this issue before but I would like to give it another shot at fixing this issue before taking the car in to a mechanic next weekend. i need this car for 3-4 more years and I have about 168,000 miles on it.

Currently check engine light is on and both coils and spark plugs were replaced only a few months ago. I change oil every 3000 miles with recommended 5W-20 oil and I changed the oil last week. Used STP fuel injector cleaner a few times this year. Last time van had some idling issues/rough before check engine light came on shortly after. This time it just came on suddenly.

Thanks!
 

·
Registered
Joined
·
629 Posts
It is a necessity here to specify your trim level.
If you have an EXL or Touring then you are probably experiencing the negative side of Honda VCM technology (hence, rear cylinders fouling up).

Scroll up to the main page of this generation and read up on those VCM muzzler. Basically, you will want to disable VCM with one of those muzzlers ($100) then wait a pray that it will clear up in a few months. Otherwise, you will need a ring job.
 

·
Registered
Joined
·
1,377 Posts
And what brand coils/plugs? Non-oem can cause issues.
When I had rough idle issues with random misfire code, I did a 'drop test' to find which coil was not firing. Replaced that one coil with a Hitachi. Problem solved
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
It is a necessity here to specify your trim level.
If you have an EXL or Touring then you are probably experiencing the negative side of Honda VCM technology (hence, rear cylinders fouling up).

Scroll up to the main page of this generation and read up on those VCM muzzler. Basically, you will want to disable VCM with one of those muzzlers ($100) then wait a pray that it will clear up in a few months. Otherwise, you will need a ring job.
I will try that, thank you. I meant to say I have 2007 Honda Odyssey EXL
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
And what brand coils/plugs? Non-oem can cause issues.
When I had rough idle issues with random misfire code, I did a 'drop test' to find which coil was not firing. Replaced that one coil with a Hitachi. Problem solved
I purchased Denso coils.
 

·
Registered
Joined
·
5,539 Posts
It seems like back 3 spark plugs and coils are going bad within 4-5 months recently. They seemed oily and dirty.

Well, that maybe your problem, leaking spark plug tube well seals.
If the ignition coils are covered with oil when you take them out, your seals are leaking.
 

·
Registered
Joined
·
3,029 Posts
Make sure you are not buying counterfeit NGK spark plugs. Commonly sold on Amazon.
 

·
Registered
Joined
·
2,032 Posts
If this problem occurs every few months, then you've got an intermittent problem. I assume your van mostly runs OK.

If the plugs look good when you remove them, and the van runs good, then ignore the codes and drive on.

Whatever you have will eventually get worse, and the problem can be troubleshot. Right now, how is anyone going to fix the van if it doesn't have a problem when you bring it in.

What codes get set?
 

·
Registered
Joined
·
182 Posts
We were getting these P030X codes on all six cylinders many times for years. We clear the code with our OBD II scanner and those codes would come back every so often especially when the weather gets colder. I think (not 100% sure) what eventually fixed the problem for us was that we were getting codes to replace the front set and then a year later to replace the back set of O2 sensors. After all of those sensors were replaced, those P030X codes any longer comes up. However, now we get the P0420 to replace the catalyst:-(. We had the VCM tuner 8 months before the O2 sensors and it did not help. Although, it will help with the engine mounts and other issues going forward unfortunately too late for the first replaced set of engine mounts for us. Is there any connection between the exhaust and the P030X code?

By the way, we replaced one coil (Intermotor Coil on Plug Coil from Advance Auto) back in January 2015 (58K miles ago) and it still works well.

We have had very good luck with 3rd party parts from Advance Auto, which our mechanic strongly suggest not to get. Another is a Remanufactured Carquest starter that is going strong after 5 years+. Although, certain parts like engine mounts, CV axle, etc., we would always try to get OEM unless we cannot justify it.
 

·
Registered
Joined
·
1,388 Posts
Maybe the oil is resulting in carbon tracking inside the coil boots, resulting in the misfire? If you get it in the back, if you move the coils to the front, does it follow the coils, or stay in the back? Might try replacing the valve cover gasket and spark plug tube gaskets, on the rear valve cover, anyway. Then clean the coil boots well, make sure you use dielectric grease, and button everything back up and see how it does.

Given the prevalence of counterfeit NGK (as well as Denso, if what I have read is correct) I would avoid buying from Amazon - stick with Rockauto or a mainstream auto parts store.
 

·
Registered
Joined
·
13,396 Posts
This sounds to me like classic VCM induced plug fouling. If you change the plugs and the problem goes away for 3-5 months, comes back with dirty plugs again, then that screams oil fouling caused by VCM. You need to disable the VCM (ECO mode) that turns off the 3 rear cylinders for fuel economy. I would install a VCMTunerII, replace the plugs again (use only NGK from a reputable authorized reseller--not Amazon or eBay,) and hope you've escaped the need to have the pistons re-ringed.

At your mileage, I'd also replace all four O2's. This could be the cause of your occasional roughness. After replacing mine at 170K it ran like a brand new car. They don't last forever. Be sure and use NTK sensors, which are the OEM.

As mentioned, if you have oil on the coils when you remove them then that's a valve cover/spark plug seal issue and you should do a valve cover gasket replacement. At your mileage you should also do a valve adjustment if it hasn't been done already, as well.
 

·
Registered
Joined
·
19 Posts
I need help and I am getting frustrated with my 2008 Honda Odyssey's check engine light that is now coming back up every few months. I have changed my Honda Odyssey spark plugs/coils at least 5 times within last 3 years and I think it might be time to take it in. I spent a lot of time trying to figure out what the root cause of this issue is and I can't seemed to pin point it. I do some work on my cars but nothing major like replacing timing belt, rebuild engine, etc. It seems like back 3 spark plugs and coils are going bad within 4-5 months recently. They seemed oily and dirty.

I don't know if anyone else had this issue before but I would like to give it another shot at fixing this issue before taking the car in to a mechanic next weekend. i need this car for 3-4 more years and I have about 168,000 miles on it.

Currently check engine light is on and both coils and spark plugs were replaced only a few months ago. I change oil every 3000 miles with recommended 5W-20 oil and I changed the oil last week. Used STP fuel injector cleaner a few times this year. Last time van had some idling issues/rough before check engine light came on shortly after. This time it just came on suddenly.

Thanks!
I had a similar issue and it resolved by valve adjustment.
Hope this helps.
 

·
Registered
Joined
·
376 Posts
This sounds to me like classic VCM induced plug fouling. If you change the plugs and the problem goes away for 3-5 months, comes back with dirty plugs again, then that screams oil fouling caused by VCM. You need to disable the VCM (ECO mode) that turns off the 3 rear cylinders for fuel economy. I would install a VCMTunerII, replace the plugs again (use only NGK from a reputable authorized reseller--not Amazon or eBay,) and hope you've escaped the need to have the pistons re-ringed.

At your mileage, I'd also replace all four O2's. This could be the cause of your occasional roughness. After replacing mine at 170K it ran like a brand new car. They don't last forever. Be sure and use NTK sensors, which are the OEM.

As mentioned, if you have oil on the coils when you remove them then that's a valve cover/spark plug seal issue and you should do a valve cover gasket replacement. At your mileage you should also do a valve adjustment if it hasn't been done already, as well.
"Eco" mode on my 2016 is independent of cylinder deactivation mode. The Eco light is not connected to cylinder deactivation mode.

The Eco mode light comes on when the mileage is about 25 mpg or greater. I can see cylinder deactivation kick in on my vacuum gauge (vacuum drops way down). Cylinder deactivation mode may or may not be active when the mileage is over 30 mpg. The Eco mode light is always on over 25 mpg, whether the engine is running on all six cylinders or when cylinder deactivation is active.

This may not be true for earlier Odysseys. Cylinder deactivation on my 2016 is very smooth, "seamless", and it's activation cannot be sensed or felt while driving. My neighbor has a 2014 with almost 100k, with cylinder deactivation, and his is also "seamless". He's had no issues with the factory cylinder deactivation setup. He didn't know about muzzlers until I talked with him about this issue.
 

·
Registered
Joined
·
13,396 Posts
On Gen 3 the "ECO" mode only indicates cylinder pause. Since this is the gen 3 forum, and his post was in regards to a gen 3 van, I didn't go into nuances of the newer models.
 

·
Registered
Joined
·
376 Posts
On Gen 3 the "ECO" mode only indicates cylinder pause. Since this is the gen 3 forum, and his post was in regards to a gen 3 van, I didn't go into nuances of the newer models.
Good. We now know the Eco light tells a different story on different generation Odysseys. The next question is - is there really any reason to "Muzzler" the newer Odysseys where the cylinder deactivation is imperceptible when it activates? Supposedly, Honda has now fixed the cylinder durability issue on these newer Odysseys, right?
 

·
Registered
Joined
·
13,396 Posts
Good. We now know the Eco light tells a different story on different generation Odysseys. The next question is - is there really any reason to "Muzzler" the newer Odysseys where the cylinder deactivation is imperceptible when it activates? Supposedly, Honda has now fixed the cylinder durability issue on these newer Odysseys, right?
My 08 Touring cylinder pause was always imperceptible--still is, though I've been muzzled since 135K and am now using a VCMTunerII which prevents VCM from activating altogether. The problems have not been fixed. The entire system is flawed and no matter what they do it will eventually give problems. GM has the same issue with their DoD engines with AFM. In that engine it damages the lifters which requires cylinder head removal to get the lifters out of the block. Often times it means a new engine. It's just a bad idea.

There are reports here all the time of gen 4 vans with carbon fouling causing misfires. I would Muzzle every engine that has this dumb system.
 

·
Registered
2015 Odyssey EX
Joined
·
2,226 Posts
"Eco" mode on my 2016 is independent of cylinder deactivation mode. The Eco light is not connected to cylinder deactivation mode.

The Eco mode light comes on when the mileage is about 25 mpg or greater. I can see cylinder deactivation kick in on my vacuum gauge (vacuum drops way down). Cylinder deactivation mode may or may not be active when the mileage is over 30 mpg. The Eco mode light is always on over 25 mpg, whether the engine is running on all six cylinders or when cylinder deactivation is active.

This may not be true for earlier Odysseys. Cylinder deactivation on my 2016 is very smooth, "seamless", and it's activation cannot be sensed or felt while driving. My neighbor has a 2014 with almost 100k, with cylinder deactivation, and his is also "seamless". He's had no issues with the factory cylinder deactivation setup. He didn't know about muzzlers until I talked with him about this issue.
The ECO light is not merely a fuel economy indicator in the gen 4 Odyssey - it would be nice if it were as simple as that but it just isn't.

My van has the VCM disabled using an S-VCM controller and I can still achieve greater than 25 mpg, especially as an instantaneous value. Throwing the van in neutral on a downhill slope and coasting should give an unbelievably high mpg value that can last for a good number of seconds, but it doesn't get the the ECO indicator to light up in my van (yes, I've tried it - my Scangauge reports an instantaneous fuel consumption value of 0.0 L/100 km). But when I disconnect the power lead of the S-VCM controller, the ECO light comes on. So regardless of how you choose to interpret what your vacuum gauge tells you, VCM and the ECO light are tied together somehow. I won't pretend that I know all the criteria Honda uses to get the ECO light to come on because I don't. But for as long as I have had our S-VCM controller installed and active (going on 18 months now), the ECO light has never once come on in any driving conditions. Not even one single flukey time.

Good. We now know the Eco light tells a different story on different generation Odysseys. The next question is - is there really any reason to "Muzzler" the newer Odysseys where the cylinder deactivation is imperceptible when it activates? Supposedly, Honda has now fixed the cylinder durability issue on these newer Odysseys, right?
This could be a dangerous assumption. I'm glad you and your neighbour are having good experiences with the VCM2 in your 2016 and 2014 respectively. But there are more than a couple of people here on Odyclub with 2014+ Odysseys who did not share in that good fortune and have rebuilt engines (the cost of which was shared by Honda, not covered completely).

There is reason to believe that the gen 5 Odysseys with VCM3 have a good chance at avoiding VCM troubles - the experiences there are generally quite good and Honda seems to have learned a lot. But us gen 4 guys aren't in that group, even with later model years. Like @John Clark said, VCM2 is a flawed system.
 

·
Registered
Joined
·
376 Posts
The ECO light is not merely a fuel economy indicator in the gen 4 Odyssey - it would be nice if it were as simple as that but it just isn't.

My van has the VCM disabled using an S-VCM controller and I can still achieve greater than 25 mpg, especially as an instantaneous value. Throwing the van in neutral on a downhill slope and coasting should give an unbelievably high mpg value that can last for a good number of seconds, but it doesn't get the the ECO indicator to light up in my van (yes, I've tried it - my Scangauge reports an instantaneous fuel consumption value of 0.0 L/100 km). But when I disconnect the power lead of the S-VCM controller, the ECO light comes on. So regardless of how you choose to interpret what your vacuum gauge tells you, VCM and the ECO light are tied together somehow. I won't pretend that I know all the criteria Honda uses to get the ECO light to come on because I don't. But for as long as I have had our S-VCM controller installed and active (going on 18 months now), the ECO light has never once come on in any driving conditions. Not even one single flukey time.


This could be a dangerous assumption. I'm glad you and your neighbour are having good experiences with the VCM2 in your 2016 and 2014 respectively. But there are more than a couple of people here on OdyClub with 2014+ Odysseys who did not share in that good fortune and have rebuilt engines (the cost of which was shared by Honda, not covered completely).

There is reason to believe that the gen 5 Odysseys with VCM3 have a good chance at avoiding VCM troubles - the experiences there are generally quite good and Honda seems to have learned a lot. But us gen 4 guys aren't in that group, even with later model years. Like @John Clark said, VCM2 is a flawed system.


I wouldn't say my neighbor and I are having good experiences with VCM. Rather, that neither one of us has had any issues or bad experiences with VCM (yet). So - here's the theory - if it works, why fix it? I don't necessarily believe that, but he does. What I have learned here is that a muzzler disables both the VCM system and the Eco light on a 2010 Odyssey. On my vehicle (2016, 20k), the Eco light functions as a "25 mpg light" with VCM active on the vehicle, on or off. I don''t know what deactivating VCM would do to the Eco light on the 2016, but I would guess that a muzzler will deactivate it, based on what you have told me. When coasting, my Eco light is also off. Mpg on the Scangauge II is maybe 300 mpg at speed, coasting, light off. Not coasting at speed - a lot less than 300 mpg, under 200 mpg, Eco light on. Coasting saves almost half, with the throttle lifted (wanna save gas - try a "pulse cruise" - accelerate fairly sharply, then coast). On older standard shift cars, and perhaps newer ones, the fuel would shut off when in gear, when the throttle was closed. When the clutch was disengaged, the mileage still improved at higher speeds, even though the engine was still using gas at idle (4 cylinder, about .4 gph at idle - Odyssey, about the same ,4 gph at idle, engine hot, A/C off, maybe due to 0W-20 oil?).

The vacuum reading is primary, meaning it is not controlled by the PCM or any other computer program. Cylinder deactivation does not function at idle, where the Eco light is off. Vacuum is an "independent" variable, independent of any computer, dependent only upon, and solely determined by, internal engine conditions, not electronics. You can believe what it says no matter if the engine is on or shut off, or at full throttle, or anywhere in between. It doesn't ever lie, VCM on or off. When the vacuum drops significantly at very light throttle, it is an active VCM system that causes this drop in vacuum. Green light not withstanding.

If you learn to use a vacuum gauge it can save more gas than a VCM system could ever save. Coasting is a part of gas savings (my concern about coasting is wearing out the shift cable). Anyone should learn this if they have a Scangauge and a vacuum gauge. The Scangauge II reads vacuum, digitally, but less visibly than a physical vacuum gauge. It would surprise most people when they see how a small, almost imperceptible throttle movement affects engine vacuum - and mileage - 1" of vacuum equates to about 1 mpg on the highway. I have been using a vacuum gauge on my vehicles for over 30 years, and they have easily paid for themselves in fuel saving (and often, I don't bother to pay attention). Some older VW's used to have an "Eco" light, vacuum operated, which could help one save a little gas if used properly.

This country would save a hell of a lot gas if vacuum gauges were standard equipment on every vehicle, and some folks would learn how to use them. The gen 4 Odyssey's instantaneous mpg indicator(s) is crude, almost unusable. It is too difficult to read to use in this way.

When the (gen 4) engine vacuum drops to 4" or less, and the mpg is over 30 mpg, that is when the cylinder deactivation is active, no matter what the Eco light says. When the mpg is around 25 and the vacuum reads 10", cylinder deactivation is shut off. Same at 28 mpg when the vacuum reads maybe 13". As you pointed out, who knows what circuit or electronics actually activates the Eco light? We already know that the 2010 VCM operates differently than my 2016 VCM2 system. When I see the Eco light on, I am getting at least 25 mpg regardless of whether VCM is active or not. If you want to see the Eco light on when coasting, it will come back on when you put the vehicle back in gear. It is off when the engine is idling, in or out of gear, moving or stopped.

At this point I think it would be a good idea for me to deactivate my VCM system. I have little to lose and perhaps something to gain. It might save 2-3 mpg when active, but almost nothing, overall, because a good part of the time, VCM is inactive. GM's AFM (VCM) saved about 1 mpg on an 8 cylinder GM vehicle I owned a few years back. The change in vibration was quite noticeable when AFM was active, and I didn't like that. It could be turned off with the performance settings in the electronics menu structure. Hondas are not that sophisticated. I'm not saying "buy GM" - mine went back to GM as a lemon (a huge hassle, to be avoided if possible).
 

·
Registered
Joined
·
6 Posts
Discussion Starter #19
Thank you all for your help. I went ahead and purchased /installed VCMTuner yesterday. Shortly after I posted this topic, check engine light went away. When check engine light was on, eco mode did not kick in. So I am hoping that VCMTuner will do the trick. I will update this discussion in a few weeks.
 

·
Registered
Joined
·
26 Posts
Thank you all for your help. I went ahead and purchased /installed VCMTuner yesterday. Shortly after I posted this topic, check engine light went away. When check engine light was on, eco mode did not kick in. So I am hoping that VCMTuner will do the trick. I will update this discussion in a few weeks.
Hi Sandin,

I would strongly recommend a valve adjustment. I had a similar issue with my 05. Check engine light would come on and flash when it was cold and the engine would go into a limp mode. If I kept the motor at about 2000 RPMs the light would not come on. Once I did the valve adjustment that fix the issue. Mine had about 185,000 on it when I did the valve adjustment.
 
1 - 20 of 26 Posts
Top