Let's Talk Spark Plugs

[charleswrivers]

From what I've seen plugs gaps will naturally open a bit as the vehicle ages from the erosion of the group and and electrode. What might be .030 and good even with folks running 23# basemaps or 24.5# TSP stage 1s may not work out as they wear towards 100k miles. Most of the plugs I've pulled seem to open up. I've done my mother-in-law's Galant twice now. It uses iridium plugs... but it starts getting a hesitation and occasional misfire at ~60k (I did the change and ~55k miles and again a little after 100k miles). Each time the gaps.were opened and I just replaced them rather than trying to tighten older plugs. That's the only vehicle I've had to change early due to running bad... but they all seem a little wide when it's been time to change them. I always gap to min spec and hope they don't wear badly out of spec. If I ever had a car than ran poorly, plugs are cheap enough to be something I'd try early on. I had heard Honda's VCM cause gap variation too on vehicles so equipped (not applicable to Civics).

Running colder plugs used to be the thing on Z32s running higher boost. The FSM even gives several plug options based on need. It is, however, covered in that manual for that specific car and that's not to say it it applies here.

Anyways... I was always told to gap to a min spec, that way it's wearing further in band rather immediately out of it.

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[jcivics]

From what I've seen plugs gaps will naturally open a bit as the vehicle ages from the erosion of the group and and electrode. What might be .030 and good even with folks running 23# basemaps or 24.5# TSP stage 1s may not work out as they wear towards 100k miles. Most of the plugs I've pulled seem to open up. I've done my mother-in-law's Galant twice now. It uses iridium plugs... but it starts getting a hesitation and occasional misfire at ~60k (I did the change and ~55k miles and again a little after 100k miles). Each time the gaps.were opened and I just replaced them rather than trying to tighten older plugs. That's the only vehicle I've had to change early due to running bad... but they all seem a little wide when it's been time to change them. I always gap to min spec and hope they don't wear badly out of spec. If I ever had a car than ran poorly, plugs are cheap enough to be something I'd try early on. I had heard Honda's VCM cause gap variation too on vehicles so equipped (not applicable to Civics).

Running colder plugs used to be the thing on Z32s running higher boost. The FSM even gives several plug options based on need. It is, however, covered in that manual for that specific car and that's not to say it it applies here.

Anyways... I was always told to gap to a min spec, that way it's wearing further in band rather immediately out of it.

Hey Charles, I started thinking about the gap I did today .028” and decided to take it out for a run. It ran great, until I stepped on it a little from a dead stop. The car starts sputtering so bad and lost all power, flashing check engine. After resetting the ECU (battery disconnect) all is fine, but I made sure not to boost over 50% . Going to check the gaps again. Do you think the coils are going bad? Also, just got a letter from Honda a few weeks ago about the powetrain warranty and misfire codes. But I know mine is probably from the Hondata tune, and new plugs . I’m at 100k miles. Or if anyone else has an idea, I’d like to hear.

Thank you

 

[jcivics]

So I gapped down to .025-.026” . Reset ECU. The first an 2nd pulls got a little stutter at 3k, I’m thinking burn off... all other pulls were smooth and torkey (is that a word? Lol). Pulled real clean from dead stops, and tons of power mid to high range. The original cel flashing happened on a cold start. Going to give it a run tomorrow cold an see how it does.

 

[jcivics]

Today I didn’t want to do it, but checked the coolant, was very low...

 

[JT Si]

Awesome! Spark plugs are fine thread, so the thread pitch would be M12x1.25mm.



We're not quite sure what this part number is, but at this time there are no other suitable/recommended plugs for these cars.



Again, there is no other suitable/recommended plugs for these cars. There is no need for a "better" or "upgraded" plug. We talked and worked directly with an NGK rep whom was in our shop and sent us numerous plugs to try. We had high hopes for their Ruthenium HX plugs, which are supposed to be their "better" plug. However, upon testing, we discovered that the factory coil boot does not fit over top insulator of the plug (white body) because the Ruthenium top insulator is too fat. This was news to NGK. Unless this has been fixed over the past few weeks (which we doubt it has), there are no other compatible plugs available.

Ruthenium Information

What part numbers did you try? I switched to Ruthenium HX on my Si about two months ago and I didn't have any fitment issues. I also greased them up with dielectric grease, so it's possible the boot slipped over more easily.

I don't recall seeing any size difference in the ceramic insulator between them, though. I compared OEM with the HX side by side as I swapped them out.

I used NGK 91784 regapped to around 0.028"

Edit: I pulled out the old plugs and checked again, there is no size difference in the insulator between the OEM Si plug and NGK 91784.

I think they didn't give you an appropriate part to try. They currently do not have a part number of the HX plugs they recommend for the 10th gen civic. I chose this part by cross-referencing all 26 Ruthenium parts against the OEM plug spec.

 

[charleswrivers]

Hey Charles, I started thinking about the gap I did today .028” and decided to take it out for a run. It ran great, until I stepped on it a little from a dead stop. The car starts sputtering so bad and lost all power, flashing check engine. After resetting the ECU (battery disconnect) all is fine, but I made sure not to boost over 50% . Going to check the gaps again. Do you think the coils are going bad? Also, just got a letter from Honda a few weeks ago about the powetrain warranty and misfire codes. But I know mine is probably from the Hondata tune, and new plugs . I’m at 100k miles. Or if anyone else has an idea, I’d like to hear.

Thank you

I haven't messed w/the plugs on the Civic yet but...

My opening question would be if it ran fine before you pulled the plugs and checked/gapped them? If it ran fine before you pulled them... then it's something you touched. Whether it's a gap issue (not likely if they're gapped both the same and consistent with each other), a plug issue itself (damaged electrode when gapping is the most likely thing), poor contact between the 'boot' what plugs into the spark plug itself, a coil issue, or a wiring issue. The things you touched would have 1) The coil pack wiring harness 2) The coil pack/boot assembly off the plug and 3) the plug itself, which you then regapped. I would check that the wiring is tight on each coil pack, and that each boot is plugged into the plugs themselves. You can use plug grease as well... which helps make a seal to keep oxidation/debris/carbon junk in the boots/wiring harness. As to whether a coil is going bad... I don't know the spec of what the coils are... and it's unlikely a coil is going bad on such a new car, but you could use a multimeter to check the resistance of the coils against each other. If one is substantially different than the others, then it would be 'bad'. It just charges a magnetic field and works based on allowing an inductive kick to occur, where voltage ramps up to thousands of volts and when the supply voltage is removed, it polarity shifts to try to maintain the current flow but, as a result, ramps the voltage up immensely (inductors will make voltage do whatever is necessary to maintain current flow, capacitors kind of do the opposite... maintaining voltage by changing current however is necessary. Very dumbed down but they're just 2 different components that are used for various applications. Both 'store' electrical energy and are used to maintain/change voltage/current to suit a need). If the resistance is different... then the amount of energy 'stored' would be different... and the magnitude of the 'kick' (which turns into the sparking event) would be different, but it's resistance value affects the current flow it's ultimately trying to maintain in the system.

There's some other more off the wall stuff (ie one plug not threaded in very much so that it's not positioned in the same depth of the combustion chambers as the others) but so long as they're torqued in properly... but shouldn't be a thing.

There's some other things... but the problems I've had with cars have either been poor performance which required the plugs to be changed... or an outright 'failure' of a cylinder, making a V6/V8 car run on 5/7 cylinders (I've never had a dead cylinder in a 4 cylinder thus far). It makes the engine run very choppy with much less power. Those times it was due to a failure of a coil pack or a failure of the plastic clip that held the wiring to the coil pack. I have had injector problems... never a failed shut but some failed open ones which has made cars run poorly. If you had a misfire issue prior to trying to regap your spark plugs, that could also be your issue. The TSP or whatever it was that added a year to parts of the powertrain warranty and talked about misfired on the L15B7 powered 2016-2018 cars could also be injector related.

I may be outspoken on this... but I tend to 'not believe' in changing wiring often... and it's certainly based on condition and not age. As with most every electrical fault I've had to correct... 99% of the time, it's not interconnecting wiring except a the connection point (ie those plastic ends you connect/disconnect from the coil packs). Even when I've had those fail, I've just put new ends on them rather than replace the whole wire. I had the wires replaced in the Z when the engine was pull some years back... but a that point, the car had 90k miles and was about 20 years old. All I'm saying is... I wouldn't consider changing wires as a corrective action on such a new vehicle so long as the connections being made are good, even with 100k miles. Blame my view on years in the navy with wiring that subject to constant thermal events and a harsh environment that last for the life of the boat... plus being in homes with wiring that pre-dated rubber insulation (asbestos FTW) that was just fine. I think a lot of the ideas of wiring wear is based on older vehicles with distributors.

Still... if the car was fine before you touched it, there's a 99% change the problem is from something you touched. Plugs... boots/coils... wiring harness to the coils. Sorry if it's a little long.

 

[jcivics]

I haven't messed w/the plugs on the Civic yet but...

My opening question would be if it ran fine before you pulled the plugs and checked/gapped them? If it ran fine before you pulled them... then it's something you touched. Whether it's a gap issue (not likely if they're gapped both the same and consistent with each other), a plug issue itself (damaged electrode when gapping is the most likely thing), poor contact between the 'boot' what plugs into the spark plug itself, a coil issue, or a wiring issue. The things you touched would have 1) The coil pack wiring harness 2) The coil pack/boot assembly off the plug and 3) the plug itself, which you then regapped. I would check that the wiring is tight on each coil pack, and that each boot is plugged into the plugs themselves. You can use plug grease as well... which helps make a seal to keep oxidation/debris/carbon junk in the boots/wiring harness. As to whether a coil is going bad... I don't know the spec of what the coils are... and it's unlikely a coil is going bad on such a new car, but you could use a multimeter to check the resistance of the coils against each other. If one is substantially different than the others, then it would be 'bad'. It just charges a magnetic field and works based on allowing an inductive kick to occur, where voltage ramps up to thousands of volts and when the supply voltage is removed, it polarity shifts to try to maintain the current flow but, as a result, ramps the voltage up immensely (inductors will make voltage do whatever is necessary to maintain current flow, capacitors kind of do the opposite... maintaining voltage by changing current however is necessary. Very dumbed down but they're just 2 different components that are used for various applications. Both 'store' electrical energy and are used to maintain/change voltage/current to suit a need). If the resistance is different... then the amount of energy 'stored' would be different... and the magnitude of the 'kick' (which turns into the sparking event) would be different, but it's resistance value affects the current flow it's ultimately trying to maintain in the system.

There's some other more off the wall stuff (ie one plug not threaded in very much so that it's not positioned in the same depth of the combustion chambers as the others) but so long as they're torqued in properly... but shouldn't be a thing.

There's some other things... but the problems I've had with cars have either been poor performance which required the plugs to be changed... or an outright 'failure' of a cylinder, making a V6/V8 car run on 5/7 cylinders (I've never had a dead cylinder in a 4 cylinder thus far). It makes the engine run very choppy with much less power. Those times it was due to a failure of a coil pack or a failure of the plastic clip that held the wiring to the coil pack. I have had injector problems... never a failed shut but some failed open ones which has made cars run poorly. If you had a misfire issue prior to trying to regap your spark plugs, that could also be your issue. The TSP or whatever it was that added a year to parts of the powertrain warranty and talked about misfired on the L15B7 powered 2016-2018 cars could also be injector related.

I may be outspoken on this... but I tend to 'not believe' in changing wiring often... and it's certainly based on condition and not age. As with most every electrical fault I've had to correct... 99% of the time, it's not interconnecting wiring except a the connection point (ie those plastic ends you connect/disconnect from the coil packs). Even when I've had those fail, I've just put new ends on them rather than replace the whole wire. I had the wires replaced in the Z when the engine was pull some years back... but a that point, the car had 90k miles and was about 20 years old. All I'm saying is... I wouldn't consider changing wires as a corrective action on such a new vehicle so long as the connections being made are good, even with 100k miles. Blame my view on years in the navy with wiring that subject to constant thermal events and a harsh environment that last for the life of the boat... plus being in homes with wiring that pre-dated rubber insulation (asbestos FTW) that was just fine. I think a lot of the ideas of wiring wear is based on older vehicles with distributors.

Still... if the car was fine before you touched it, there's a 99% change the problem is from something you touched. Plugs... boots/coils... wiring harness to the coils. Sorry if it's a little long.

No problem. I believe I’ve narrowed it down to a leaking head. As I said , I got the multiple misfire (means not a single coil) on cold startup. After checking the coolant overflow, it was dry. After filling up with water, some oily substance floating at the top, not much though. When I took off the cap (cold), big pressurized rush, scared me. Also can hear water running through the a/c. Luckily it hasn’t overheated and running stock ecu now will not cause pressure spikes, going to take it in and see what happens. Thanks for your feedback though, it’s appreciated.

 

[charleswrivers]

No problem. I believe I’ve narrowed it down to a leaking head. As I said , I got the multiple misfire (means not a single coil) on cold startup. After checking the coolant overflow, it was dry. After filling up with water, some oily substance floating at the top, not much though. When I took off the cap (cold), big pressurized rush, scared me. Also can hear water running through the a/c. Luckily it hasn’t overheated and running stock ecu now will not cause pressure spikes, going to take it in and see what happens. Thanks for your feedback though, it’s appreciated.

Good luck. You definitely want to get it fixed asap. You're losing coolant... and it's either going to the environment or into the oil. Either one is bad as you're losing coolant that'd keep the car from overheating... emulsified oil is worse... as it won't do its job in lubricating the engine (it'll look milky, from the water and oil being churned and mixed up). Hearing the water in the A/C might actually be from the heater core where you're getting bubbles entrained in the coolant since it's run so low causing the flow noise.

Good luck with the fix. So long as it's caught early, it could be as (relatively) simple/cheap as a head gasket replacement. The gasket itself isn't expensive, other than the few hours of labor to replace it.

 

[jcivics]

Good luck. You definitely want to get it fixed asap. You're losing coolant... and it's either going to the environment or into the oil. Either one is bad as you're losing coolant that'd keep the car from overheating... emulsified oil is worse... as it won't do its job in lubricating the engine (it'll look milky, from the water and oil being churned and mixed up). Hearing the water in the A/C might actually be from the heater core where you're getting bubbles entrained in the coolant since it's run so low causing the flow noise.

Good luck with the fix. So long as it's caught early, it could be as (relatively) simple/cheap as a head gasket replacement. The gasket itself isn't expensive, other than the few hours of labor to replace it.

I’m fkin pissed at my tuner guy. He was authorized Hondata dealer so I went to him thinking he may be able to help me. All he did was drain my wallet. Hondata says that the cvt will be fine with the +6 and I didn’t need anything else. I knew I should have just bought the Hondata and not gone to this guy but my cc payment wouldn’t go through on the website and I knew this guy had Hondatas in stock , of course when you buy one, you must pay for a dyno session. He didn’t even know which fkin calibration setting to use... fk ahole. It was fun for a little bit tho. Ran 230hp and 220ftlb , whoosh, bend head. I’m almost 100% that’s what happened, too much boost. I’ll get back when it’s confirmed official. Btw, coolants not physically leaking on the ground,
it’s just being burned off now, that’s why misfires happen. By leaking I meant through the gasket into the cylinder. Can’t fire a plug when water/antifreeze in the chamber. In another note, the smaller gapped plugs have been doing well, combusting good with whatever amount is leaking for now. I’m sure it’s small because the stuff in the Reservoir tank is very very minimal

 

[mikey003]

In this day and age, your spark plugs will outlast any other component on your vehicle,

Your car will rot and rust to the ground before you need new spark plugs,

We are beyond the years of replacing spark plugs, serpentine belts, and rad hoses every 5 years,

those items now (in most cases) pretty much last the lifetime of your vehicle

 

[r.camlin]

I’m fkin pissed at my tuner guy. He was authorized Hondata dealer so I went to him thinking he may be able to help me. All he did was drain my wallet. Hondata says that the cvt will be fine with the +6 and I didn’t need anything else. I knew I should have just bought the Hondata and not gone to this guy but my cc payment wouldn’t go through on the website and I knew this guy had Hondatas in stock , of course when you buy one, you must pay for a dyno session. He didn’t even know which fkin calibration setting to use... fk ahole. It was fun for a little bit tho. Ran 230hp and 220ftlb , whoosh, bend head. I’m almost 100% that’s what happened, too much boost. I’ll get back when it’s confirmed official. Btw, coolants not physically leaking on the ground,
it’s just being burned off now, that’s why misfires happen. By leaking I meant through the gasket into the cylinder. Can’t fire a plug when water/antifreeze in the chamber. In another note, the smaller gapped plugs have been doing well, combusting good with whatever amount is leaking for now. I’m sure it’s small because the stuff in the Reservoir tank is very very minimal

How much boost? The +6 tune should be perfectly safe to run on a CVT, unless something was messed with that shouldn't have been messed with. 230hp and 220tq does not sound like too much, but there's a lot more to a tune than just horsepower and torque.

Also it's almost impossible to accurately dyno a CVT.

 

[charleswrivers]

In this day and age, your spark plugs will outlast any other component on your vehicle,

Your car will rot and rust to the ground before you need new spark plugs,

We are beyond the years of replacing spark plugs, serpentine belts, and rad hoses every 5 years,

those items now (in most cases) pretty much last the lifetime of your vehicle

That sort of depends how long you keep your vehicle. 5 years is pretty soon for them all... but replacing the hoses during a timing belt change on an interference engine when they have to pull them off anyways or are getting well hardened or a serpentine belt when it shows wear so it doesn't break, kill you alternator and leave you stranded if you're a long way from anywhere isn't a bad idea. I've had both radiator hoses crack and leak and belts break while I've been out on some of my older cars and neither was very fun. They got that way from not having been done in the intervening years and I was too young/cheap/broke to be proactive.

As to plugs? They may last well more than the estimate a lot of times... though mileage trumps age. Some vehicles seem to run perfectly well even when they're due for replacement. I've done them on old vehicles that appeared to have the original plugs and there was no proof of them ever being having done previously. Part of the issue is getting them out of an aluminum head without damaging the threads if they leave them in too long. They can be a bear to get out. If you wait too long, the damn things don't want to come out. Iridiums last longer than platinums and coppers... but they don't last forever. When I've pulled them early from poorly at evenrunning vehicles at 60k, they were out-of-spec wide.

Used to O2 sensors on Honda's/Acuras lasted pretty much the same as iridium plugs. I swear over on the RSX forums, they went out right around 100k like clockwork. Not sure if that's still a thing. I had mine go out just over 100k miles within 10k miles of each other in 2 different cars.

 

[jcivics]

How much boost? The +6 tune should be perfectly safe to run on a CVT, unless something was messed with that shouldn't have been messed with. 230hp and 220tq does not sound like too much, but there's a lot more to a tune than just horsepower and torque.

Also it's almost impossible to accurately dyno a CVT.

Not sure. I think +3 . In any case, I just know there’s a breach in the head gasket. It’s been hot as hell lately and that heat and the tune fkd it up. I’m getting a diag done soon, I’ll keep posted. Also my cars is at 100k miles. Driven hard.

 

[r.camlin]

Not sure. I think +3 . In any case, I just know there’s a breach in the head gasket. It’s been hot as hell lately and that heat and the tune fkd it up. I’m getting a diag done soon, I’ll keep posted. Also my cars is at 100k miles. Driven hard.

High torque and high boost at low RPM is bad news. +3 is by no means too much boost, but there's obviously a lot more to the story here.

 

[mikey003]

I've had both radiator hoses crack and leak and belts break while I've been out on some of my older cars and neither was very fun.

uuummm, yeah, re-read my post please,

i wasn't talking about "older cars"

i thought that was clear when i said "in this day and age"

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