Hey guys yesterday I did the spark plug change on my STR. To be honest this was my first time doing it on any car and I followed VAnce's spark plug youtube video which was a tremendous help, thanks Vance!
Whatever you do make sure you have quality tools like the Spark Plug socket and the extension drives and universal swivel. I learned it the hard way, I had some cheap ones from Advance Autoparts and I ran into some huge problems. The dam Spark Plug socket got stuck inside the Plug well, the rubber in the socket got twisted inside and I couldn't pull it out with the drive extension, kept slipping off , took a good while to slowly wiggle it out with the extension drive, but anyhow I went over to SEars and bought some Craftsman tools there and yes a good quality 5/8 Spark Plug socket , lesson learned! Anyhow I was thinking I stripped the thread in which I started doing first toward the deep end of the drivers side, but as I kept turning Counter-Clockwise it kept getting tighter and tighter I'm like WTF!! , but anyhow it came out. To my surprise it was NGK iridiums long life just like the same ones I bought to replace them with new. But the most noticeable thing standing out was the condition of all the plugs. All my plugs that I pulled out had heavy carbon build up all the way to the tip of the Plug(check pics). I can't believe my STR was running still great with these plugs on in this condition so I thought,lolz.
Check out the pics I took close ups with and you'll see what I'm talking about(More or less all of them look the same all 8). NGK Iridiums long life must have been the OEM's. Because when I bought my car at 65k the original owner never changed out the plugs he told me, and this got me thinking that even VAnce had the same issue when he changed out his plugs, but his was in a lot better state than mine. I will give an update how she runs with the Plug change and Mafioso's "Better" dual coated Intake installed very soon.

The only thing I couldn't do which really upsets me was the TB cleaning, lolz...its way over my head and very tedious at the moment for me to do on my own

Cheers.

 

I hate to say it but it looks like a couple of the plugs are fouled. I think you have a couple of rings going bad in your motor... How many miles are on it?

Do you ever have to add oil to it?

I would seriously do a compression check on each cylinder. It may be valve problems that would be alot better than rings.

It will run great for awhile until the new plugs foul out with oil.

 

Wow those are horrendous. Could it be from the valve cover o-rings?

 

I have never seen a set of iridium plugs look anything even close to that bad. I agree, you've got some engine issues going on. Let us know what you find out once you do some investigating....

 

What makes you think it was running great? Got OBD readings of things such as fuel trims?

 

Looks like deposits from low grade gasoline!

 

Agree with the others, that is not what you want to see when you pull the plugs out. A compression test would be a good place to start as mentioned above.

 

I'd say exactly the opposite, if you mean low grade as in 'poor additive package'.

Has the OP been pouring additives into the tank?

How has the oil consumption been?

 

Wow man I didnt realize your plugs were gonna look like that. Check out this chart I usually check mine to a chart like this.

Your look like the ash deposits. As a few people stated might be from a previous owner using lower octane gas. Here is a site for some insight as too what could be the cause.
Interpreting your spark plugs
It talks about additives like Mikey replied. So if you havent been putting in additives and using premium fuel may of been from the previous owner. Since all the plugs are like that it may not be the valve guides like that link says. I would run premium for a bit and dont put in any additives and try to stick too one gas station and run it for a few thousand miles and pull a plug and see if it looks like you got ash deposits again. I'd say 5000 miles check them again. Are you consuming oil? If you do that and see deposits you should know you might have some valve guides going.
Now that I look at some of them on a few of them you have some oil deposits on them so those cylinders might be having some trouble. So it looks like you have a few different things going on. Did you happen to label which cylinder you pulled what plug from. I probably should of put that in my video. I usually will label the boxes of the new plugs and as I replace one at a time I'll put the old ones back in the box with which cylinder it came from for reference later.
Also your threads look a little moist was there oil in the plug wells. They should of been dry. That could be a sign that you have some oil getting in there which could be the rings or valve seals. If its still running good and you are checking oil and not losing any I would do what I said above and check again in 5000 miles.

 

Actually, I meant the opposite. Not 'low/inadequate' additives, but possibly 'excessive or incorrect' additives.

It's got NOTHING to do with octane levels, that's a myth!

That web site you quoted has been around since the days of leaded gas so the ash comments don't really apply in the same context.

 

Some of his plugs has carbon/ash build up...but a couple are heavy oil fouled.
He really needs a compression test done as soon as possible.

 

Oh ok I get it about the octane not meaning anything. My next line I was actually saying the same thing about excessive additives refering to that link but I didnt word my response like that. The link states that the ash deposits comes from fuel or oil additives being burned so if you have excessive ash deposits like a few of those plugs would indicate excessive additives. So yea what Mikey said. LOL.

 

First off sorry if the pics are huge and you have to scroll side to side to see it. Someone pointed it out to me..... I'm using a Mac and on my screen they fit fine.

I'll just answer all the questions here in one big response, lolz... My STR has now almost 85k, I bought it at around 65k. Thanks Vance for that chart you shared, its exactly the "ASH" type due to rich fuel mixture or adding in additives. The previous person I'm sure didn't put the high octane stuff or added some kind of additives.

Secondly...the moist oil on the plugs isn't that bad as it looks like on the pics, I had a rag that was moist with throttle body on it that might have made it look worse than it is when I was holding them. I couldn' t see any oil in the plug wells. Plus the car was driving great ever since I bought it last year. I have to fill the oil atleast half quart every 3 or 4 months but thats expected right? I'm getting close to 100k and I'm sure its normal to see a little moistness on the plugs.

UPdate on test driving. I did the hard reset procedure and put it in Sport mode and gunned it! , I think I jizzed in my pants once I stomped on the gas pedal jk, amazing with the Magnaflows I still was able to hear the SC whine and the K&N sucking in the air. With the new plugs installed and Mafiosos intake it certainly made a difference from before and hopefully I should be getting even better gas milage now. Ever since I bought my STR last year I have been putting nothing but the highest octane. Now come to think of it, I realize why the CATS went bad and I had them changed out to the HI-Flows b/c of the previous owners negligence to use low octane gas

 

OK, one more time- the deposit you see is NOT from 'low octane gas' or 'low quality gas'. It wouldn't have caused what you see here, and no matter what the P/O used, the deposits would be long gone by now anyway.

This is being caused by a condition that's still present, something that you're doing.

 

I hope your right but the 5th and 7th pic front the top to bottom are oil fouled not just oil from a oily rag.
Seriously if it was mine I would do a compression test for piece of mind.

Time will tell but if the rings are weak the new plugs will soon foul out

 

Mikey - thanks. Thoughts about what would cause them to look that way?

 

Hey guys,

Thanks, I'll eventually do a compression test, sooner or later I'll have to replace the O rings anyways. I promise ever since I bought the car I never added anything to it, no additives no nothing. Those plugs must be OEM, since the previous owner mentioned to me that he never touched the plugs only did the routine maintenance on it. Since in my possession I just fill her up with high Octane gas thats about it. So what makes the ASH look on the spark plugs like on VAnces Chart he posted up? It can't be just adding additives to cause that. I'm going to take my plugs to my local Jag mechanic and have his say on it also and I'll tell you guys what he said, or maybe I can get Brutal to chime in on this,lolz....

Not too long ago I changed out my CATS, b/c the honeycomb inside of them were deteriorated. I started noticing the slight sound ever since buying it last year, then at one point it got louder and starter irritating me so then I took action to get it replaced both sides. My guess is that the previous owner must have added some kind of additives or what not to cause such problems. Hopefully now that I have the HI-flow CATS and new plugs I should be ok, but I will have to monitor the moist oil residue on the plugs. Those two pics of the plugs were toward the deep end near the TB both right and left sides.

 

Has anyone done Water Decarbonization? The procedure involves spraying/trickling water into your intake plenum/manifold. The high temperatures during the combustion event cause the water molecules to explode into steam, causing micro-shockwaves that dislodge the carbon buildup from the cylinder head, walls, and valves. The water removes heat from the combustion chamber by a state change (liquid to gas) and will allow the engine to use a lower octane fuel and get the same performance as higher octane fuel. OR should I just use SEAFOAM?

 

I have heard of that but have never done it or heard about anyone ever doing it. My curiousity with that is where does the carbon go when its dislodged?

 

Hi Vance,

According to this thread Water Cylinder Decarbonizing... Should I? - Car Forums and Automotive Chat,

It says the carbon should shoot out of the exhaust