So on saturday morning my check engine light came on. I had just done a few nitrous runs but didn't think much of it. The car was idling a bit worse but I just blamed it on the colder plugs. So I decided to go to Autozone to get the codes pulled rather than just resetting the ecu. Misfire on cylinders 1, 2, and 4. Also a "random misfire" code. I decided not to worry and just assumed it came from one of the nitrous runs, so I cleared the codes. However, about an hour later on the highway using cruise control the check engine light came on again. I assumed the spark plugs had built up some deposits from running too cold and might need to be replaced. After the pain that is removing the plugs (are there any other cars where you have to remove the windshield wipers to change the plugs?) I found this...













The cylinder 1 and 2 spark plugs have center electrodes worn INTO the insulator, at least 3 or 4 mm. I have no idea how the spark was still jumping the gap. The 1 and 2 insulators are blistered and speckled but not cracked. I simply can not comprehend how they could have worn like that. I haven't seen a single spark plug in any spark plug condition charts that looks like that. The insulator looks like preignition though. The 3 and 4 plugs look great which certainly means whatever happened, occured under N2O. In the 3rd picture, both bad plugs have a nearly identical defect in one of their gorund straps. It almost looks like someone dropped a bead of solder on the ground strap. Does this mean it almost melted?

Anyway, I went down to winner's circle (in the t-bird) and bought some copper ngks 2 steps colder than stock and cleared the ecu. After installing the plugs the misfire is gone of course. The engine seemed to be running back to normal. Is this that legendary Honda reliabilty? Where I can cause detonation/preignition in 2 cylinders and still have her run like a champ?

About why it happened. On Friday, I was messing around on the highway and decided to just open it up when I was getting needlessly tailgated by some random (probably base model) Impala. I was in the middle lane and the left lane was open for him to pass me. When I used the 'go baby go' juice I was not expecting it to keep accelerating so hard after 100 and I hit the maximum speed limiter. Unfortunatley for me I had removed the fuel pressure safety switch just the day before!!! So I likely had nitrous flowing into the engine with no fuel, causing an ultra lean condition. Somehow, the engine continued running mostly fine and I drove the rest of the way to work. It drove home fine too, not even a check engine light. The light did not finally come on untill a coworker and I went on a lunch run and I opened up the nitrous again.

I just finished doing a few quick nitrous pulls and will check the new plugs again soon.

 

holy large pictures batman... resize those things

 

I would want to take a look @ the pistons, but if it's running.... well it's runn'n.

Can you get a hold of a snake cam? run it down the sparkplug hole?

 

I don't know anyone with one :/ I have a feeling it's not an autzone rental item either.

 

Wow those electrodes are seriously WORN.

I'd say your "lean" explanation makes sense. I do flog my engine, but after checking my recent last change of spark plugs their electrodes were all intact.

Take care next time man.

 

aye. the 4 of those went in at the same time about 2,000 miles ago and came out at the same time. In all of the spark plug condition pictures, under preignition or detonation, the insulator is always cracked and damaged when the center electrode is worn down that much. It boggles my mind.

 

Now that I think about it, I can probably rule out detonation since their was no knock sensor code stored in the ecu. That just leaves preignition without detonation. If it where a Chrysler, I would probably have left a rod and a big puddle of oil somewhere out there on the highway.

 

NICE!

 

WOW. The obnoxiously large images have melted the spark plugs!

 

Home Deopt sells this and they have a rental side in most of their stores... I'm just curious what happened to the top of pistons 1&2 when the heat was turned up

 

Hope all is well with your engine.

 

Don't make me paranoid I've been indulging thoughts of trading in the fit and just taking a loss before I blow up the fit for good. I bought the fit for practicality and reliabilitly but now I value neither of those things.

 

So then go further with it. Talk to a company about some pistons for it and build it up. Drop compression a bit or bump it UP (the way I would go), there are nay-sayers here that think 10.4:1 is not really high, but that is higher than the B16 that was ever released in the US, by .2:1. It's a slow car, but it is so much fun to drive. I don't miss my Snisen as much as I thought I would, but do still miss my old 5R Teggy, it was just TOO much fun.

Anyways, straying off...again. Ultimately it's your choice to make whether to keep or move on. Best of luck with the Fit and its heart.