Misfires on 3 cylinders—likely evap issues, flooded charcoal canister led to misfires (2021, 75K miles)

[HSTexan]

If this was my car, I would have so much emotional instability lol.

From head gasket to coil pack to EVAP to electrical gremlins...

@HSTexan hang in there!

It’s certainly been an anxiety inducing 5 days; the one comfort I can take is at least now they’ve seemed to move past the head gasket stuff and it’s looking a lot less like a catastrophic failure and more like some weird gremlins.

 

[Zill]

I would take an electrical gremlin over a 15-30k engine replacement bill any day of the week.

 

[GrouchyTech]

Plot thickens...

I can't say any of this is for sure, but the LRA can interact in unexpected ways. There's a possibility that what is happening is during an EVAP purge cycle (hence not readily reproducible). And there so much vapor and fuel going into the intake that it's causing mis-fires.

Why it's only on one bank, I'm not sure. I believe the purge valve is plumbed back into the plenum where it should be distributed evenly, but stranger things have happened.

It’s possible to active test evap purge while driving and record how the fuel trims, misfires, etc. respond.

 

[studawg]

So now no misfires and only evap codes. Makes me wonder if neither is the actual problem and the real problem is electrical which can present in totally different and unrelated ways. Water intrusion, bad ground, bad battery?

 

[HSTexan]

So now no misfires and only evap codes. Makes me wonder if neither is the actual problem and the real problem is electrical which can present in totally different and unrelated ways. Water intrusion, bad ground, bad battery?

Since the LRA breather looked ok we're going forward with the charcoal canister. Battery health is good and is only about 3 years old--it's hooked up constantly to a small hood solar that keeps it topped off and I can see the stats on the battery at all times. I've brought up the water intrusion multiple times and gotten them to dig all around and look and they can't find any sort of corrosion or signs of water that had gotten on electrical components.

Given how bad the spark plugs looked, there is still a decent chance they were misfiring. Why they looked that bad at 75K is another mystery. But evap issues could certainly cause misfires in some conditions. If this doesn't work it may be getting shipped up to Slee to have them dig into the LRA and install.

 

[gasman4u]

Since the LRA breather looked ok we're going forward with the charcoal canister. Battery health is good and is only about 3 years old--it's hooked up constantly to a small hood solar that keeps it topped off and I can see the stats on the battery at all times. I've brought up the water intrusion multiple times and gotten them to dig all around and look and they can't find any sort of corrosion or signs of water that had gotten on electrical components.

Given how bad the spark plugs looked, there is still a decent chance they were misfiring. Why they looked that bad at 75K is another mystery. But evap issues could certainly cause misfires in some conditions. If this doesn't work it may be getting shipped up to Slee to have them dig into the LRA and install.

I had a litany of evap issues with my LRA which ultimately didn’t have a solid “why” associated with it. No misfires, and no lean, etc codes and had the classic p4xx codes showing evap issues. No topping off. No overfilling main tank. Still had a saturated charcoal canister. Ended up having to go to a couple different “recommended” places and ultimately had it solved by a specialist in another state that did great work. I would think slee would be solid as a definitive source for a solution if indeed it’s your LRA. I also ended up removing my “upgraded” air filter on LRA’s advice and put in their little $hitty on. No codes since. Still have a bnib charcoal canister on hand (long story) should that come up again. It sounds like you’ve got a dedicated shop of techs for now digging in. I’m glad it’s not your HG, but still frustrating nonetheless.

Hang in there and please keep the thread updated.

 

[BIC JET]

Thanks for this. IMO,, please don’t buy o’reilley parts and put it in our rigs (oil filters not withstanding).

Ladies & Gentlemen, it is a test. Only a test.

 

[GrouchyTech]

I had a litany of evap issues with my LRA which ultimately didn’t have a solid “why” associated with it. No misfires, and no lean, etc codes and had the classic p4xx codes showing evap issues. No topping off. No overfilling main tank. Still had a saturated charcoal canister. Ended up having to go to a couple different “recommended” places and ultimately had it solved by a specialist in another state that did great work. I would think slee would be solid as a definitive source for a solution if indeed it’s your LRA. I also ended up removing my “upgraded” air filter on LRA’s advice and put in their little $hitty on. No codes since. Still have a bnib charcoal canister on hand (long story) should that come up again. It sounds like you’ve got a dedicated shop of techs for now digging in. I’m glad it’s not your HG, but still frustrating nonetheless.

Hang in there and please keep the thread updated.

This could be key information going forward.

 

[Artie]

Since the LRA breather looked ok we're going forward with the charcoal canister. Battery health is good and is only about 3 years old--it's hooked up constantly to a small hood solar that keeps it topped off and I can see the stats on the battery at all times. I've brought up the water intrusion multiple times and gotten them to dig all around and look and they can't find any sort of corrosion or signs of water that had gotten on electrical components.

Given how bad the spark plugs looked, there is still a decent chance they were misfiring. Why they looked that bad at 75K is another mystery. But evap issues could certainly cause misfires in some conditions. If this doesn't work it may be getting shipped up to Slee to have them dig into the LRA and install.

The pinkish plugs are something that keep coming to mind… I had a long day in the car and this thread kept creeping into my mind in between personal thoughts of a few of my own cruiser projects I’m going to try to tackle this weekend.

Do you always, or very often, get gas at that same 7/11? Pink plugs, as already mentioned, can come from fuel or additives.

All the LRA/EVAP issues could be the cause of the CEL issue but those shouldn’t cause pink plugs.

 

[HSTexan]

I had a litany of evap issues with my LRA which ultimately didn’t have a solid “why” associated with it. No misfires, and no lean, etc codes and had the classic p4xx codes showing evap issues. No topping off. No overfilling main tank. Still had a saturated charcoal canister. Ended up having to go to a couple different “recommended” places and ultimately had it solved by a specialist in another state that did great work. I would think slee would be solid as a definitive source for a solution if indeed it’s your LRA. I also ended up removing my “upgraded” air filter on LRA’s advice and put in their little $hitty on. No codes since. Still have a bnib charcoal canister on hand (long story) should that come up again. It sounds like you’ve got a dedicated shop of techs for now digging in. I’m glad it’s not your HG, but still frustrating nonetheless.

Hang in there and please keep the thread updated.

What ended up being the fix for you besides changing the breather filter?

The pinkish plugs are something that keep coming to mind… I had a long day in the car and this thread kept creeping into my mind in between personal thoughts of a few of my own cruiser projects I’m going to try to tackle this weekend.

Do you always, or very often, get gas at that same 7/11? Pink plugs, as already mentioned, can come from fuel or additives.

All the LRA/EVAP issues could be the cause of the CEL issue but those shouldn’t cause pink plugs.

Yes I'd say 95% of the time if I'm filling up locally it's at that 7/11

 

[gasman4u]

What ended up being the fix for you besides changing the breather filter?



Yes I'd say 95% of the time if I'm filling up locally it's at that 7/11

The charcoal canister got swapped to a new one. Besides that, the final (excellent) shop basically unf@ked what the one shop did to my rig to “fix” it. Given the chain of events, I don’t know that the LRA supplied vs little crankcase breather filter I had on it made any difference. Plumbing was unchanged iirc. I will be putting on a filter wears universal sock soon when I swap out my in line fuel filter as PM.

Even good gas stations sometimes have issues. I’ve seen some weird stuff in my short time on this planet. Again - your dealership seems like there trying to suss this out appropriately. Given what you’ve said, I’d trust them

 

[Artie]

Even good gas stations sometimes have issues.

Agreed. I keep going back to the gas station/pink plugs. There’s no way of knowing what’s really in those underground tanks and I’ve had weird behaviors after filling up once before in our Cruiser and it took a few fill-up’s for it to rectify itself. We were on a trip and towing so it was pronounced at first but no CEL.

 

[HSTexan]

Well the charcoal canister arrived yesterday and they got at it this morning. Advisor just called me and let me know they just got the canister out and it was absolutely full of gas--to the point where when the tech disconnected it, it spilled all over his face. The running theory is that the flooded canister dumped so much vapor and potentially even excess liquid fuel back into the intake plenum where it vents which caused a super rich condition for an extended period of time and fouled the plugs early and caused the misfires issues.

My LRA has been installed since 02/24 and I've used it a ton. I probably should have been letting it sit empty periodically so the canister doesn't have to work as hard on 48gal of gas and has a chance to recover, but with how much I've been driving in the past 4-6 months it seems like every time I gassed up I was filling both tanks. I am always extra careful never to top off the tanks because I feared this, but I have definitely boiled gas before so I don't doubt fuel ran back down into the canister.

They're going to wrap up getting the new one installed, then drive it today as well as tomorrow with pick up slated for tomorrow afternoon

As a side note, does anyone know if the connection between the filler necks is above or below the line for the charcoal canister? Curious if forgetting to turn off the transfer pump and letting it fill to the point it's got to drain back into the tank is below the canister line.

 

[CanadianRockyCruiser]

Well the charcoal canister arrived yesterday and they got at it this morning. Advisor just called me and let me know they just got the canister out and it was absolutely full of gas--to the point where when the tech disconnected it, it spilled all over his face. The running theory is that the flooded canister dumped so much vapor and potentially even excess liquid fuel back into the intake plenum where it vents which caused a super rich condition for an extended period of time and fouled the plugs early and caused the misfires issues.

My LRA has been installed since 02/24 and I've used it a ton. I probably should have been letting it sit empty periodically so the canister doesn't have to work as hard on 48gal of gas and has a chance to recover, but with how much I've been driving in the past 4-6 months it seems like every time I gassed up I was filling both tanks. I am always extra careful never to top off the tanks because I feared this, but I have definitely boiled gas before so I don't doubt fuel ran back down into the canister.

They're going to wrap up getting the new one installed, then drive it today as well as tomorrow with pick up slated for tomorrow afternoon

As a side note, does anyone know if the connection between the filler necks is above or below the line for the charcoal canister? Curious if forgetting to turn off the transfer pump and letting it fill to the point it's got to drain back into the tank is below the canister line.

And some mechanic thought your cylinders were f***ed. What a world.

 

[Zill]

Well the charcoal canister arrived yesterday and they got at it this morning. Advisor just called me and let me know they just got the canister out and it was absolutely full of gas--to the point where when the tech disconnected it, it spilled all over his face. The running theory is that the flooded canister dumped so much vapor and potentially even excess liquid fuel back into the intake plenum where it vents which caused a super rich condition for an extended period of time and fouled the plugs early and caused the misfires issues.

My LRA has been installed since 02/24 and I've used it a ton. I probably should have been letting it sit empty periodically so the canister doesn't have to work as hard on 48gal of gas and has a chance to recover, but with how much I've been driving in the past 4-6 months it seems like every time I gassed up I was filling both tanks. I am always extra careful never to top off the tanks because I feared this, but I have definitely boiled gas before so I don't doubt fuel ran back down into the canister.

They're going to wrap up getting the new one installed, then drive it today as well as tomorrow with pick up slated for tomorrow afternoon

As a side note, does anyone know if the connection between the filler necks is above or below the line for the charcoal canister? Curious if forgetting to turn off the transfer pump and letting it fill to the point it's got to drain back into the tank is below the canister line.

Fingers crossed that does the trick! That’s excellent news if it does. Way better than a new engine!

 

[gasman4u]

Well the charcoal canister arrived yesterday and they got at it this morning. Advisor just called me and let me know they just got the canister out and it was absolutely full of gas--to the point where when the tech disconnected it, it spilled all over his face. The running theory is that the flooded canister dumped so much vapor and potentially even excess liquid fuel back into the intake plenum where it vents which caused a super rich condition for an extended period of time and fouled the plugs early and caused the misfires issues.

My LRA has been installed since 02/24 and I've used it a ton. I probably should have been letting it sit empty periodically so the canister doesn't have to work as hard on 48gal of gas and has a chance to recover, but with how much I've been driving in the past 4-6 months it seems like every time I gassed up I was filling both tanks. I am always extra careful never to top off the tanks because I feared this, but I have definitely boiled gas before so I don't doubt fuel ran back down into the canister.

They're going to wrap up getting the new one installed, then drive it today as well as tomorrow with pick up slated for tomorrow afternoon

As a side note, does anyone know if the connection between the filler necks is above or below the line for the charcoal canister? Curious if forgetting to turn off the transfer pump and letting it fill to the point it's got to drain back into the tank is below the canister line.

Wouldn't the increased volume of fuel in the tank actually lower the vapor pressure? I may be misunderstanding how the canister keeps the vapor pressure from venting to the atmosphere however. I'd imagine it is likely from your fuel boiling (vapor and atmospheric pressure equalizing) if I had to guess. Or maybe forgetting to turn off the transfer pump? Either way, it's a good news: bad news situation. I hope this gets you back online in short order!

 

[HSTexan]

And some mechanic thought your cylinders were f***ed. What a world.

Yep--I'm absolutely not thrilled about that and plan on brining that up when I get it. I'm pretty sure someone looked at it, they immediately called me because they saw something wrong. Rather than get a secondary opinion, they called me trying to update me ASAP and gave me bad info. Just going to suggest that in the future they wait for second opinions before telling customers of catastrophic failures. Or at least wait until they've done more than a 2 min scope

 

[HSTexan]

Wouldn't the increased volume of fuel in the tank actually lower the vapor pressure? I may be misunderstanding how the canister keeps the vapor pressure from venting to the atmosphere however. I'd imagine it is likely from your fuel boiling (vapor and atmospheric pressure equalizing) if I had to guess. Or maybe forgetting to turn off the transfer pump? Either way, it's a good news: bad news situation. I hope this gets you back online in short order!

That does make sense and to be completely honest I'm not nearly as well versed in the evap system. I do know that at the root cause if this really is the fix, it's for sure from the LRA and from me not being careful enough. I need to be much safer about turning off the fuel transfer and keeping it low enough that if I boil gas on the trail it doesn't boil high enough to run up and out of the filler neck. And maybe just for good measure stop working the aux tank so hard

 

[rexington14]

Glad you seem to have got this sorted. Still a bit strange that it only misfired on one bank - probably just coincidence. I assume all 8 plugs were equally carboned up? May as well inspect or just replace the PCV now.

 

[CanadianRockyCruiser]

Yep--I'm absolutely not thrilled about that and plan on brining that up when I get it. I'm pretty sure someone looked at it, they immediately called me because they saw something wrong. Rather than get a secondary opinion, they called me trying to update me ASAP and gave me bad info. Just going to suggest that in the future they wait for second opinions before telling customers of catastrophic failures. Or at least wait until they've done more than a 2 min scope

It's probably worth having a competent mech test all the EVAP system components. Or just take the LC to the crusher...it's a write off