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corroded coil wire and other fun things


s_frost

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Hi, again. So today I treated my car to some denso iridiums (the ik-20s) and some NGK he62 wires, all to replace the BS I got screwed into paying someone to install two or three years ago, though I myself have tampered around with things since then. when I was pulling off the coil wire, a bunch of black dust fell out. I poured it out of the wire onto a papertowel, then removed the coil and cleared it out of there, too. at first I thought the entire metal piece had corroded but it turned out the wire had slid pretty far out of the boot, and how in the heck electricity had been going through it all that time, I don't know. anyway, the plastic end of the coil that the wire plugs into is a bit destroyed. the metal inside is fine, though, no corrosion. should I replace the coil or is it fine?

 

also, that coil is a tek 21-a, which is usually used for the six-cylinder engines (mine is the non-vtec 4 cylinder). when I replaced the coil a few years ago, I was desperate, the aftermarkets didn't fit my housing, and that's all they had. the technicians at the dealership said it'd be fine, but for some reason I've never been comfortable with that.

 

anyway, in addition to all this, my lower tube seals are starting to leak. before I'd only done the upper seals, but now the lowers are going, too. do these really need to be changed? one of my technician friends waved his arm at it and said, "Oh, don't even worry about that." I don't like the thought of oil being all up in there, but I'm wondering what others think. I don't really want to remove the rocker assembly not necessarily for lack of technical ability but for lack of guts to risk screwing something like that up.

 

on a final note, turns out one of the old spark plugs had the washer stuck at and angle, which means it probably hadn't screwed down as far as it should have. that's not a problem now, but would that have had a negative effect on the car? I've had a P0420 code, which apparently is super notorious, but I've heard that when the car gets old and starts operating out of spec it can start throwing that code. the CEL was off as soon as I started up the car, but that's probably because I disconnected the negative battery cable for doing all the work.

 

thoughts, suggestions, comments? I like to learn from the more experienced.

Edited by s_frost
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1. Ignition Coil: Plan on replacing the coil if you suspect the wire to have caused damage to the resin inside the coil. In the least, check resistance across the primary and secondary coils to be sure the unit is within spec.

 

2. Spark Plug washer: only if the washer being at an angle allowed combustion gasses to escape. Was there signs that this occured? You didn't mention heat scoring inside the spark plug tube or carbon built up along the spark plug insulator or burnt plastic on same.

 

3. Spark Plug lower seals: replace them. Take a picture of the assembly before removing it, take a picture when you get it out, that way if you drop it or decide to take it apart you have a reference to how it goes back together. I've dropped one and some of the pieces came apart, it wasn't hard to look at the rest of it and figure how it goes back together.

 

4. P0420: replace the Ignition Coil, then check and/or replace both Heated Oxygen Sensors (HO2S). Only then look at the Catalytic Converter. The ECU doesn't know if it is getting bad data, has a bad catalytic converter, or a good catalytic converter is being overwhelmed by unburnt fuel. The only thing its doing is measuring the difference in voltage between the two HO2Ss when it generates that P0420 and only does so when it gets a voltage it does not expect.

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1. Ignition Coil: Plan on replacing the coil if you suspect the wire to have caused damage to the resin inside the coil. In the least, check resistance across the primary and secondary coils to be sure the unit is within spec.

 

2. Spark Plug washer: only if the washer being at an angle allowed combustion gasses to escape. Was there signs that this occured? You didn't mention heat scoring inside the spark plug tube or carbon built up along the spark plug insulator or burnt plastic on same.

 

3. Spark Plug lower seals: replace them. Take a picture of the assembly before removing it, take a picture when you get it out, that way if you drop it or decide to take it apart you have a reference to how it goes back together. I've dropped one and some of the pieces came apart, it wasn't hard to look at the rest of it and figure how it goes back together.

 

4. P0420: replace the Ignition Coil, then check and/or replace both Heated Oxygen Sensors (HO2S). Only then look at the Catalytic Converter. The ECU doesn't know if it is getting bad data, has a bad catalytic converter, or a good catalytic converter is being overwhelmed by unburnt fuel. The only thing its doing is measuring the difference in voltage between the two HO2Ss when it generates that P0420 and only does so when it gets a voltage it does not expect.

 

1. yeah, I may look into that. that coil was dang expensive, but I don't like it being damaged on the outside. checking the resistence would I guess be best to do first. I forgot to mention too that it's been without a third metal washer for some time, and I don't know if that causes a grounding issue or not. when I did all this the other day I put in one of my spare coil washers from the junkyard. it might just be good to play it safe and get the 4-cylinder tc-19a instead (that was the actual designation. I forgot it, but was close).

 

2. I didn't notice any signs of scoring, although there was some brown burnt-like discoloration where the insulator meets the shell/case. I'm pretty sure that's just a sign of age, since all of them had a little bit of that (these were cheap-o plugs they put in, too, so I'm not surprised)

 

3. Yeah. I may just have to suck it up and do it. I do have the helm manual, which might be enough, but I still like the picture idea. I actually have the o-ring seals from a set I got from advance, but when I did the valve cover and the upper seals, I had no idea what they were for. but if I'm taking the cover off, I may as well get another set with everything in it, since the cover gasket is two years old now

 

4. I actually did replace the upstream sensor and cleared the code, but this past week, six months later, it came back on. I'm half tempted not to care, though downstream sensors don't cost all too much, and my car seems old enough that any new parts seem to help

 

Thanks for the thorough response. I appreciate it.

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In many cases the 420 code is affected by environmental changes. Different times of year the code will not return for a while if it is cleared. I operated my 99 for years this way. In the winter it would trip weekly, in the warmer months it never came on. I had a scanner and would just reset it as necessary. Having the code on caused a noticeable drop in mpg for me. This was after replacing a pair of sensors and a cat. I too, just lived with it instead of throwing more money at something no one was figuring out.

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1. Those washers are not for ground, they're so the coil mounts to the bracket properly.

 

2. That brown discoloration is normal on used plugs, not a sign of abnormal wear.

 

3. Yeah: Suck it up.

 

4. Those should be replaced in pairs. You could do like 'Xeryon' and pretend the light doesn't exist. I can't stand lights on my dash.

Edited by James Matteu
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