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I need to replace my spark plugs. I realized that they have alphabetical code specific to each car (A,B, C or D). Here are my trouble:

1) I have no idea how to remove the plug, even after taking off the plastic cover for the cylinder head. I saw the 3 plug with cables connected it each top of it, but they look so different from other car sparkplug outside part thus I have no idea on how to apply a sparkplugs wrench to turn and remove them.

2) Also I am bit unsure, should I remove each of the cable connected? If yes how?

3) I thought the alphabetical sparkplug code reference will be easily found on the cylinder head next to each plug, but so far I haven't seen any of the code.

4)What size of sparkplug wrench can be used? & how tight it need to be (torque)?

I may upload pictures later.

Thanks for your attention.:)
 

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You have not seen the spark plugs yet......What you are looking at are the coil packs on top of each spark plugs. The Insight does not use a distributor, each plug is fired from an individual coil.

You have to disconnect the wiring harness to each coil pack. Remove the single bolt holding each coil pack in place (10mm socket). Remember what cylinder each coil comes from so that it can be put back in the same cylinder (not that it will not work if they are mixed). Only after you remove each coil pack will you see the spark plug. There should be a stamped letter on the cylinder head by the spark plug hole. You will not be able to see this stamp until the coil pack is removed. Note the stamped letter and purchase the appropriate set of spark plug based on the letter stamped. Honda online sources are cheaper......Once you receive the new plugs, you will know the socket size to use.

The plugs only need to be changed every 105K miles.

Hope that helps.

JoeCVT = Just your average CVT owner
 

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Discussion Starter · #3 ·
Thanks Joe

Thanks for the answer/info Joe, I appreciate it.

My Insight is only 75K and it is 2001 production line; though, it was out from dealer lot early 2002. Now I am still hesitating if it really needs to have spark plug replacement. As far as I remember the manual said 7 years or like you mentioned "105K". Personally I could not comprehend why the manual suggest 7 years, make it sound like perishable produce. What if the car barely used or still sitting on a dealer and only have few miles on it after 7 years?:-? Is this marketing issue rather than technical issue?

One more thing is how tight (torque) it is supposed to be?

Thanks again.
 

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Thanks for the answer/info Joe, I appreciate it.

My Insight is only 75K and it is 2001 production line; though, it was out from dealer lot early 2002. Now I am still hesitating if it really needs to have spark plug replacement. As far as I remember the manual said 7 years or like you mentioned "105K". Personally I could not comprehend why the manual suggest 7 years, make it sound like perishable produce. What if the car barely used or still sitting on a dealer and only have few miles on it after 7 years?:-? Is this marketing issue rather than technical issue?

One more thing is how tight (torque) it is supposed to be?

Thanks again.
I did mine a few weeks ago. Pretty much as Joe said. I didn't have to completely remove the coil packs, I was able to leave them connected and just push them out of the way (so no mix ups on reinstall).

Pretty sure I used the smaller 5/8" socket for the plugs. I cleaned them with brake cleaner per my manual. They really didn't look bad, although I have a new set to go in at 65k miles. That is normally as long as I would ever go for plugs.

Hand tighten "snug" but don't go crazy. A little force with the rachet is enough.

These are pregapped, so I didn't mess with the gap. When I swap plugs, I will see if I notice any difference. If not, I will leave these in for 100k.

Regards,
Jerry
 

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I was able to see the stamps by the coil packs before I even removed the coil packs.

Mine were all B - what did you guys have?
 

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I was able to see the stamps by the coil packs before I even removed the coil packs. Mine were all B - what did you guys have?
Before I forget to mention, the torque for the spark plugs according to the service manual is 17 ft lbs. Apply a small amount of anti-sieze to the threads and start by hand so you don't cross thread. It is important to tighten these to proper torque so the indexed plug lines up in the proper position. After all, that is why we buy the indexed plug A,B,C or D to begin with. If you look at the new plug before inserting, you can predict the orientation of the ink stamp letter on top of the plug will end up once torqued.

Perhaps Honda stamped the letters in different places on other model years or perhaps it is the evironment that your car goes through over 100K miles but my letter stamp was very hard to read even after the coils were removed. I could only read the center cylinder stamp. I can not imagine being able to read mine with the coils installed. Also, of the three bolts holding the three coils in place, 2 out of 3 had to be drilled out due to so much rust/corrosion. The socket would just spin and there was no depth left to get something like vice-grips in there. It basically looked like a corroded rivet after years of sitting through several New Hampshire winters. The one I did get off with the socket, it just barely broke loose. I replaced all three with stainless steel bolts and created a metal cover so that any water would not drip on top of them anymore while driving. This cover kind of extends the top of the "real" valve cover further out towards the catalytic converter area so it is sort of an umbrella for the coils. There have been many complain about one or two coils failing due to corrosion expanding the metal causing the coil to eventually crack. This cover may fix that problem in the future.

Many people have already posted what they have for spark plug letter stamps in previous threads and it seems agreeable that the most common by far is the letter B and a distant second place is the letter A. Letters C and D seem to be rare. All three of mine were letter A. The spark plug will also have an ink stamp letter on top. I was able to predict where the top of the ink letter A (the pointer) would point to in terms of a clock dial (like this one will point towards 3 o'clock) once properly torqued. A cool way to verify proper installation. :)

JoeCVT = Just your average CVT owner
 

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As a follow up, I changed my plugs today at 66k. I cleaned them recently and they didn't look bad, but comparing the old to the new, you can definitely see some wear.

Swapped plugs, (smaller 5/8 spark plug sockert), used antiseize (very small amounts), torqued to 17 lbs, and took it for a spin.

Car seems much crisper, easier to get into and hold lean burn, with AC off, I can acutally accelerate very gently in lean burn without falling out! Mileage ona 20 mile test trip headed upwards very nicely. Addied about 8 mpg in 20 miles, with 40 miles on the tank.

I know these plugs are supposed to be good for 105k miles, but I think I am going to use 60k as the change interval. They are a little expensive for plugs, but it is easily a DIY, so no labor to worry about. On a scale of 1-10 of difficulty, I would have to rank this around a 2.

Regards,
Jerry
 

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I still dont know where to look for the stamp on the block. I just had the cover off and the coil removed and I still did not see a letter stamped on the block. I am sure I am looking in the wrong place. Could someone describe EXACTLY where the letter is stamped on the left side spark plug...thats the one that I have off....

I have had a 10mpg drop in mileage recently and the plugs are at 120K
 

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Jim,

Some people posted that they could see a stamp on all three cylinders but when I did mine, I could only see it on the middle cylinder so you may have to take off another coil to check. The stamp is on a small flat spot right beside the area that you insert the spark plug.....

If you have corrosion around that area, you may need to clean off the area a bit and use a flashlight held at different angles.

I could never see the outer two cylinder stamps no matter how hard I looked. Since your plugs are probably original and as conformation to the cylinder head stamp, you should also see a letter ink stamped on top of each physical spark plug.

Hope that helps.

JoeCVT = Just your average CVT owner
 

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I looked very closely, but I didn't see a letter stamped on mine too, I had to remove the coil to find out which plug I had.
 

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I will look closer tomorrow, but I didnt see a flat spot near the plug hole. I saw a flat "ring" about 1/4" wide around the top of the hole. Unless you are talking about down inside the hole where the plug is??? I cant see down there without a mirror.

I will be buying a dozen of the Denso 4506 plugs as they seem to fit the specifications. Then I intend to index the plugs correctly by using various thickness copper washers under the shoulder to get the proper orientation.

My one thought is that if the manufacturing process is very exact, all the Denso plugs will have the same orientation, they shouldnt be random. But even if they are random AND I cant find plugs that match what I need, I should be able to adjust the orientation with copper washers.

Why would I do that? Because at $3.50 each they are inexpensive and they have the proper electrode (cone tipped), they are double platinum, and correct reach. They only lack the "indexing" mark. And, why not, its a neat experiment.

I might also try the E3.68 plugs. They have an interesting electrode and if indexed with the open side toward the center of the combustion chamber they should present a great flame front.

The fact that both these plugs have a flat shoulder rather than the tapered shoulder of many American car plugs, makes indexing with washers easy.
 

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Jim:
Be aware that the Insight (Gen-1) plugs are 1" long on the threaded portion and they have a iranium (sp) center rod and tip on the ground tab.

Right now I'm right in the middle of testing a set of AUTOLITE xp 5325's in the Little Red Rocket as an experiment also. They are a little shorter in the center insulation (maybe a diffference in heat range) so the side grounding tang doesn't protude into the combustion center as much as the original plugs. (1/16" less) The grounding tang on two of the plugs were within tolerances when installed but one was 180 degrees off after installation. (No matter how I switched them between cylinders) Someone posted a picture showing the difference between the plugs, but I can't remember who.
Also it is a cost thing. the AUTOLITES were $6.45 each I believe.

I think I put the installation mileage of the plugs on the CD I gave you under "Insight Cost".
After 3,000 miles it is hard to come to a conclusion as to any loss in mpg. My driveing is usually in "Sport Mode" and I see no difference in the performance.
I hope you have tabulated the thickness of the copper gaskets for indexing. Maybe removing the standard sealing washer?

After 3,000 miles I can't see any difference in the mpg or power. I believe it would have to be a controled scenerio to make a valid judgement. (Too many variables involved) After 5,000 miles I'll be reinstalling the old std. plugs as they only have about 75,000 miles on them. (Lets see what the coloring on the insulation looks like.)

That's my opinion.
Willie
 

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I will not remove the standard washer, but will add a piece of copper washer in addition to the standard washer. OR, I may try just using the crush of the original washer to make the adjustment. I wont know till I try it later today.

Yes, adding a washer will pull the plug back a bit, but I doubt it will make that much difference. As to calculating the amount, I will just determine it empirically using different thicknesses till I get the orientation I want..

All the plugs I am testing have the 1" reach and all the specs are identical except for the indexing markings. I also am ordering some of the Autolite plugs to test.

But if you are not seeing any difference maybe I am wasting my time worrying about indexing.
 

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Jim,

Some people posted that they could see a stamp on all three cylinders but when I did mine, I could only see it on the middle cylinder so you may have to take off another coil to check. The stamp is on a small flat spot right beside the area that you insert the spark plug.....

If you have corrosion around that area, you may need to clean off the area a bit and use a flashlight held at different angles.

I could never see the outer two cylinder stamps no matter how hard I looked. Since your plugs are probably original and as conformation to the cylinder head stamp, you should also see a letter ink stamped on top of each physical spark plug.

Hope that helps.

JoeCVT = Just your average CVT owner

The stamped letters are not easy to see. It takes some careful cleaning to expose them. And a wirebrush is preferrable to cleaning the electrode with solvent and the 'cone' around it. Do regap them in any case as visually they are pretty certain to be out after a few thousand miles. Make sure to bend the elctrode carefully and check afterwards. If you don't regap the spark gap is likely to be oversize and resulting in a weaker spark which naturally leads to less mpg. The wrench is 5/8"; use a self-holding wrench because if you drop the plug into place you can easily reduce the spark gap so the engine runs fine at low speed but not as well at higher rpm. good luck.
ps: wspark plugs wear out with the number of times it fires and the severity of the effort, not by time. If you run your insight at 5000 rpm expect plug life shortened considerably. cheers.
 

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I will look closer tomorrow, but I didnt see a flat spot near the plug hole. I saw a flat "ring" about 1/4" wide around the top of the hole. Unless you are talking about down inside the hole where the plug is??? I cant see down there without a mirror.

I will be buying a dozen of the Denso 4506 plugs as they seem to fit the specifications. Then I intend to index the plugs correctly by using various thickness copper washers under the shoulder to get the proper orientation.

y.
Neat idea but be aware that as you retract the electrode you will shroud thespark; it may not matter on an Insight but it sure does on 427 Nascar engine.

PS you can index yourself by marking the connector tip and reentering until the plug gap faces the intake valve.
 

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Well, I finally got down to the flat spot at the side of the sparkplug. Havent gotten the plugs out yet because I cant find my 3/8" x 3" extension!!!

BUT I did find that all my plugs should be "B" which is good, all are the same. Once I find one with the proper orientation I just have to match two more.
 

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The Honda plugs are clearly marked in TWO places. They are marked on the top of the metal cap of the ceramic insulator where there is a metal stamped B and also on the outside of the metal ring that is the gasket seat where it says ////////JAPAN/////////"B"/////. Both markings are stamped into the metal so no amount of wiping can wipe them off unless you are using a disk sander to "wipe" them...#:cool: If you are having a problem reading the stamp, maybe you are not looking at the right stamp or you have plugs that were replaced by a PO and were NOT stock....as mine are NOT now...:cool:

I replaced mine with Autolite Iridium XP5325. I bought 6 of them and picked the three that I used by indexing them so that the ground electrode was directly AFT so the flame front would progress directly forward, toward the center of the combustion chamber.

Someone suggested having the flame front progress toward the intake valve. I dont think this is the right way to do it because the intake valve will be closed at the time the mixture is ignited and in fact it will have been closed for 1/2 of a revolution, as will the exhaust valve. Their position is irrelevant at this point. But the majority of the explosive mixture will be in the center of the combustion chamber so I want the flame front to advance that way.

Further, in removing the old plugs, all were the correct NGK ("B") plugs, I noted that all were oriented within 40 degrees of straight forward...i.e. toward the center of the combustion chamber. One was 40 degrees to starboard, one was 10 degrees to starboard and one was 10 degrees to port.

If you think about it, the tolerance is 180 degrees. The reason that the tolerance is so large is that with only 4 possibilities for the plugs that means any "letter" represents a 90 degree range. And with the same tolerance for the holes in the head, they too have a range of 90 degrees. Now if the plug is at the extreme end of its tolerance and the hole is at the OTHER extreme of its tolerance then this makes the over all tolerance to be 180 degrees!!

So if the flame front progresses toward the front of the engine at all, it is within Honda tolerance!!!

But I have all 3 of mine now within 10 degrees of facing straight forward, toward the combustion chamber center, just as I think it should. I did this by selecting my plugs from a set of 6 stock Autolights. I will return the other 3 to the parts store as being out of tolerance for my car.

Willie doesnt seen to think orientation makes much difference, and I tend to think he may be right. BUT...and this is just a subjective feel....it did seem to idle smoother when the new plugs were in...#:cool: And the old plugs looked fine, but they had seen 110K miles so it was time to remove them.
 

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I know these plugs are supposed to be good for 105k miles, but I think I am going to use 60k as the change interval.
I too think 105k seems excessive. But agree with Jim's "if it ain't broke don't fix it" too.

I just had the CAT replaced on my 02 CVT w/ 68k and I think replacing the plugs might be a good idea. The honda tech told me the factory recommendations are 7 years or 105k for the plugs, so for a 2002, its past the 7 year deadline.
 

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I too think 105k seems excessive. But agree with Jim's "if it ain't broke don't fix it" too.

I just had the CAT replaced on my 02 CVT w/ 68k and I think replacing the plugs might be a good idea. The honda tech told me the factory recommendations are 7 years or 105k for the plugs, so for a 2002, its past the 7 year deadline.
Without lead in gasoline, with Insight spark plugs plated with the very stable metal iridium, with the much more precise fuel-air mixtures that can now be attained, and with spark plug misfires setting diagnostic trouble codes, spark plugs can last much longer than in the past. Those who have replaced spark plugs at the recommended 105k intervals have commented about how clean and good the spark plugs appear.

Also, I don't think that spark plugs degrade much, if any, over time, so the 7-year replacement interval feels like a generalization that is made with all maintenance items. Some things like engine oil do degrade over time, so replacing it when it reaches a certain age makes more sense.
 
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