I have a turbo charged 2008 R18 civic. I was misfiring 20,000 miles ago. Cleaned the fuel injectors, put new K&N cold air intake filter on, did spark plugs and coils. Ran great.
Fast forward 8 months later, having the same issue.
My question is:
Do boosted/tuned cars go thru spark plugs like crazy ? ( 20,000 miles seems like little life span even if I beat on the car )
Should I buy a good scan tool to figure out which spark plug is bad? Or should I just replace all 4 since there probably not far behind (I’d assume) but 20,000 miles , 8 months new for the set.
Also used all authentic NGK parts and went 1 step colder as the tune is set for that.
Spark plugs can be visually inspected. The ignition system might be better diagnosed with a scan tool if you do not have equipment or expertise to do it any other way. Certainly, the scan tool will show you what the engine management system is detecting and reporting as a fault. Is the engine light flashing when it misfires?
When you deviate from the factory set up, then all bets are off on how often parts will fail or need replacing. It is up to you to monitor, inspect and correct problems as they arise. Only then can you answer the question, will my car go through XYZ faster because of what I have done?
I used to go one step colder on the plugs because I beat on the car.BUT THAT WAS 70 YEATS AGO!
You are trying to outguess today’s factory engineers and asking on a general automotive forum.
You might get better answers from a Honda tuner forum if one exists but I have never read good results from anygood source fir tuner chips or K&N cold air intakes.
I don’t know what kind of environment you have been driving in but that K&N may have let in a lot of dirt.,
The only helpful advice I can give you is pull and read your plugs.
The filter company I worked for tested K&N air filters among others to see how they performed against our air filters.
When talking the tech who did the testing, I asked about how the K&N filters performed. He said, “If you’re looking to keep birds and chipmunks out of your engine, that’s the filter to use”.
Scan tool will be awesome, I’m getting same one I was lended before and it’ll actually show which cylinder and how many misfires. So if cylinder 2 has 84 misfires and rest are cleared it’ll be nice to pinpoint the problem.
Unless it’s not an isolated misfire.
Just wanted to make sure about plug life, I know OEM cars can go half its life without the plugs ever being touched. So 6-8 months new seemed VERY off. Especially getting NGK and not cheap knock offs.
Another test done many years ago used a flow bench to test 3 top name filters and a $1.99 cheap filter from the local parts house, the filters were the standard old school 14x3" (IIRC) round filters, they had to duct tape 1/2 (50%) of the filter element for the flow bench to be able to work, the filters (all 4) 1/2 clogged (duct taped off) still flowed 3,000 cfms, to loosely put it in perspective, a 454ci BBC engine turning 6,000 rpms running 100% efficient (usually safe for a street engine) only requires a 788 CFM carb, same 454 turning 7,000 rpms requires 920 CFMs, meaning that you could have a 75% cogged filter and it still would have not affected the performance of that engine… (CI x max RPM / 3456)
I am one that does NOT recommend air filters often unless they are very dirty, I also don’t travel on gravel and or dirt roads, nor do I have to drive through construction dust clouds.. But even at that, you can just smack them on the ground and knock the loose dirt out… I have gone over 75K on the OEM air filter before on multiple vehicles, changed them out and my MPG change was zero… My 2006 Corolla air filter was ONLY changed once in over 180K miles… If it is dirty change it, if under warranty, follow the scheduled maintenance so warranty is not void… Heck I never changed the CAF in the 06 Corolla either, one day I noticed the A/C was not working very well, I checked the CAF and it was clogged, I used compressed air to blow it out and re-installed it and never had another issue out of it or the A/C…
Until you have error codes I wouldn’t even assume a misfire (unless the engine light has been blinking at you in which case you should shut the car down). And given a misfire code(s) - (P030x) - no guarantee that the problem is the plugs. It often is, but not always.
As far as plugs go, many vehicles are very “picky” about plugs and using exact OEMs is the way to go. No cross-referenced brands/numbers, no “upgrades” or changed to metals, etc.
And while you should mostly wait for codes before doing anything, if we all had to stand around blindfolded tossing darts, I’d try to throw one at the square that says something like “get rid of that K&N filter, and clean your MAF sensor”
The situation is, if I feel the bad spark misfiring when gassing the car, if I let off and coast, it’ll stop.
But if I boost add tons of fuel + air + bad spark that’s when the engines like woah! It won’t throw CEL, but say I feel the misfires and FLOOR the car while it’s misfiring I can easily get the flashing check engine limp mode activated. I just don’t intentionally do that.
So I don’t have a code but I can get one pulled in 10 seconds if I wanted too lol.
To answer your well you don’t have CEL. I do , I just don’t trigger it.
Does it misfire all the time or only under certain conditions like wide open throttle at high RPMs? If the latter, did you upgrade the fuel pump when you added the turbo?
If it is doing it all the time, I’d start with cleaning or replacing the MAF sensor. K&N type filters (oiled cotton) are bad about gumming up the MAF sensor.
