Take a look at my spark plug

[Dojo2000]

http://www.fbody.com/members/Dojo2000/DSCN0896.JPG
http://www.fbody.com/members/Dojo2000/DSCN0899.JPG
http://www.fbody.com/members/Dojo2000/DSCN0900.JPG
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this is the spark plug from cylinder 1 that had the wire that was cracked and burnt from the exhaust manifold. Could this be my problem in this this post? What could cause the spark plug to look like this?

Right after I got it out it started pouring rain outside so I don't have a chance to put a new one in yet. don't mind it being broke, that happened while I was takeing it out.

[bu-bye]

Oh boy, Its been a while since I had to look at plugs to figure out the problem. I think the White look you got going is from running lean. Again its been way to long for me to remember. You might want to checkout google for "Spark plug color" or something like that. Or you could just wait till someone else posts. :D

[Fireman]

Ok i found a scematic with what the plugs look like under different problems kind of hard to match a pic to a black and white phot so i will list all them and should give u something to look for.


1. electrodes eroded , light brown deposits = normal wear

2. carbon fouling (black, dry, fluffy deposits)= faulty high tension lead (s) or sticking valve (s)

3.oil fouling (wet black deposit)= worn engine components

4.lead fouling ( grey,black,red,green,tan, or yellow deposits which appear glaced or cinderlike) =combustion by products

5.gap bridgeing ( deposits lodged between the electrodes)= incomplete combustion , or transfer of deposits from the combustion chamber.

6.overheating ( burnt electrode, and extremely white insulator with small black spots) ignition timeing advance to far ,, overly lean fuel mixture ,, spark plugs not seated properly.

7. pre ignition (melted or severely burned electrodes , blistered or cracked insulators , or metallic deposits on the insulator) = incorrect plug gap ,,, ignition timing advanced too far ,,,spark plugs not being cooled efficientl ,,, fuel mixture too lean ,,, poor compression fuel grade to low..

ok thats all in writing now my fingures hurt but most of ya already probably knew most of them..

and from the pics i would have too agree with bu-bye looks like it was a lean burning plug

[Dojo2000]

If you look in my pics, you can see the spark plug is sitting on top of my Haynes manual, its got those pictures in there. I just can't match it up close enough to any of them. Guy at Advanced Auto parts ( :rolleyes: i know, i know, but i respect his opinion) says its looks like it was running too rich. Dunno
Its still raining like a mofo so I haven't been able to put the new plug in yet.

[Fireman]

I hate rain when u have to work in it. it looked like it was but i don't have a hanyes and wasn't sure if it had the same diagrams as a chilton. also i thought if it was running rich the plugs would be wet when pulled out. maybe i am wrong and am thinking of something different.

[Dojo2000]

Well the threads were wet, but the electrode is burnt, not a white-carbon color and not a black color so i'm kinda lost

Its STILL raining :mad:

[John_D.]

It's hard to say... The plug is a little out of focus. The lettering on the book, a couple of inches beyond the plug is great...

How does this plug look, compared to the others? That will tell you as much as anything. If it's the same, then ok. If it's noticeably different, then that's another story.

The black spot is from where you brushed up against some oil when taking it out, right?

The plug doesn't really look bad to me, from what I can tell in the picture. How many miles are on it?

It may have built up some deposits, if the wire was bad for a while, that have mostly burned off now if you have fixed the wire. I say "mostly", because sometimes when this happens, you get a very thin baked on coating on the insulator when the plug starts firing again and burns off the junk that accumulated on it. That coating allows some or most of the spark to bleed off the center electrode, instead of jumping the gap.

If you were running lean, or had preignition, the insulator would be blotchy looking, or might even have small (very tiny) chunks out of it around the rim at the very top.

Since you obviously have to replace the plug now anyway, the real test will be when you get it all back together, and see if the problem went away.

A bad plug will cause some strange results, because besides misfiring intermittently, it can throw the o2 sensor reading off, and the pcm will start trying to correct for it, which actually throws the other good cylinders out of whack. But the pcm doesn't know this, because it averages the readings of all three cylinders on that side and thinks everything is cool...

Partly depends on if it sees the misfire and cuts the fuel to that cylinder. But it can't cut the air... So either way, the o2 sensor will most likely be seeing too too much oxygen, and will throw more fuel at that bank, which besides cutting down on performance, will tend to foul the other two plugs.

Sorry for the long answer. Just rambling along here... [img]smile.gif[/img]

[Dojo2000]

I appreciate the long answer, lets me know someones interested in helping me.

I didn't get a chance to pull any other plugs, i dread changeing all the plugs. That black spot is not oil, its some kind of deposit. Its not on the plug now so it most have gotten knocked off. Plug has around 25k mi on it. I understand what your saying about the deposits, that may possibly be the case.

I finally got a the new one in, but its still nasty and drizzleing outside so I just went for a quick ride. Didn't help my problem at all!
Someone told me that I should try to reset the pcm after fixing the plug wire, so I'm gonna try that.

[John_D.]

Sorry that the new plug didn't fix it...

Hopefully the pcm reset will help. You may need to change all three on that side.

I don't remember, did you scan for any codes too? What codes did you get?

Was this related to the stumble at 20% load thread too, or was that somebody else...?

Make sure the obvious things are ok. No other broken/burnt/loose wires. No loose or cracked vacuum hoses.

Beyond that, you are probably looking at a bad sensor somewhere. Hopefully getting the code(s) scanned will point you in the right direction.

[Dojo2000]

Nope, resetting didn't help either. I pulled the PCM Bat & IGN PCM (or whatever its called) fuses and turned on the ignition, did this twice.

Yeah, this is related to the stumbling post. I'm pretty sure its a couple of the plugs that are bad, I just dread the job of changing them. I replaced all the old and/or burnt wires already.

I've got a code for MAF sensor circuit, low input
, and EGR valve system performance. They've been coming on and off for about 2 months now, stumbling just started 2 weeks ago. I really don't think they're the problem, but maybe they could caused this over a period of time.

I do have a cracked vacuum hose on the TB, its the little one with the 90 degree boot that sticks out on the left side. Its the boot that has a small crack in it that doesn't even go up to the tip of whatever its sitting on. I wrapped it in teflon tape and painted it with liquid eletrical tape about 3 months ago. i don't have a clue where the other side of the hose leads too, so I haven't tried to replace it. Its been like that longer than I've had the codes so I don't think thats the problem. But what do I now [img]graemlins/dunce.gif[/img]

Another thing I'm trying to figure out is what wires are better to use with the tubular manifolds; the straight boot like on the like on the Accel wires or the 90 degree boot on the Taylors? With the '96 manifolds its a very, very tight squeeze for the straight boot on my Accels. The end of almost every boot rests on the heat sheild. Will there enough room to use the straight boots on Accels or are Taylors better with tubular manifolds?

[John_D.]

Sorry for taking so long to get back. Haven't been on here in a few days.

The egr could be it, if it is sticking open. It could be getting progressively worse. (any buildup on the pintle will get worse and it will stick more often and longer).

I disconnected the tubing from mine, blocked off the intake and the exhaust where the tubing used to be. Left the wires hooked up to it. I still get a code.

Not the same code as I get if the wires are unhooked though. Apparently the pcm expects to see a blip in the map sensor reading when it triggers the egr, and if it doesn't see this, then it knows the exhaust isn't getting through, even though the valve electrically opened as commanded. So you will probably get a code if you do the blockoff plate approach at the egr valve too.

The maf sensor could be part of it, if it is telling the pcm the wrong air flow. It could cause the engine to run rich or lean, but at 20% load, the o2 sensors should still be feeding back to the pcm, so the pcm should be immediately correcting for a faulty maf reading (except at wot). You might get surging, but probably not cutting out.

That vacuum hose... I'm not sure where it goes either, off the top of my head. It may go to the brake booster. If I pull that hose off while the car is running, it just about dies. If that boot is leaking, it would probably run poorly at idle, and get smoother at 20% load. So that's probably not it.

I'm still thinking plugs and wires first. (I know, yuck...) Maybe egr second.

Oh, and on that pcm reset, you have to turn the switch on, then take the fuses out. Sounds like you took the fuses out first, then turned the switch on. Try this as the quickest, easiest attempt first. Probably won't be it, but at least it will rule it out.

[Speed Freak]

Same thing hapend to me when a squirl for some dumb reason decided to chew my wires and they were arcking under load.