Spark plugs running lean, is this real?
Thread Starter
TECH Apprentice
Joined: Dec 2001
Posts: 351
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From: CA
Spark plugs running lean, is this real? It seems like my plugs are all kind of whitish. The thing is I autotap and wide band dyno and I'm not running lean anywhere.
I was thinking, maybe it is white because at partial throttle, the PCM is always tuning the AF to run at 14.7? What do other peoples spark plugs look like? Alittle whitish at the electrode? Or maybe it's because I'm using NGK TR6 which have a different heat range?
Thanks.
<small>[ September 06, 2002, 08:31 PM: Message edited by: akw408 ]</small>
I was thinking, maybe it is white because at partial throttle, the PCM is always tuning the AF to run at 14.7? What do other peoples spark plugs look like? Alittle whitish at the electrode? Or maybe it's because I'm using NGK TR6 which have a different heat range?
Thanks.
<small>[ September 06, 2002, 08:31 PM: Message edited by: akw408 ]</small>
Re: Spark plugs running lean, is this real? & b.t.w. if your lean enough to see it on plugs they show signs of overheat ,stressed porceln ,dicolored ground electode but I bet you would know it's lean long before looking at plugs. Checking plugs for your tune is ok for nitro hemi's & 9000 rpm nascar smallblocks ,but it's just not accurate for street cars.
TECH Addict
Joined: Feb 2002
Posts: 2,319
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From: Lewisville, Texas
Re: Spark plugs running lean, is this real? AKW 408,
First off you didn't provide enough information on your set up to determine wether or not you need to be using the TR-6 plugs, they are best suited for use with NOS. If you don't have NOS you should be using TR-55's, and gray is good, it shows that you are burning most of the hydrocarbons in the fuel. I would be concerned in the the plugs were black at the A.F ratio you have.
Mark
<small>[ September 08, 2002, 12:44 AM: Message edited by: Elite_Hot_Rod ]</small>
First off you didn't provide enough information on your set up to determine wether or not you need to be using the TR-6 plugs, they are best suited for use with NOS. If you don't have NOS you should be using TR-55's, and gray is good, it shows that you are burning most of the hydrocarbons in the fuel. I would be concerned in the the plugs were black at the A.F ratio you have.
Mark
<small>[ September 08, 2002, 12:44 AM: Message edited by: Elite_Hot_Rod ]</small>
Thread Starter
TECH Apprentice
Joined: Dec 2001
Posts: 351
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From: CA
Re: Spark plugs running lean, is this real? Thanks for the feedback guys.
It's not extremely white, but it is whitish. The porcelain around the center electrode looks like it has some deposits, it's alittle dirty. Nothing that I'm too worried about, I think.
I do use N2O so that's why I'm using the NGK TR6s. I just wanted to check to see if all my cylinders were running about the same in terms of AF. But I couldn't really see much difference, all I know is that they're all kind of whitish. I recently changed my fuel injectors, so I'm going to put new plugs in and take a look, but just concerned about the whiteness.
My AF is around 11.5-12.9 at WOT on the dyno.
So what do others have on their plugs? Could a few list what plug they use and the color? Maybe even a pic? I'd put a pic up of mine, but I lent my digital camera out to my gf.
It's not extremely white, but it is whitish. The porcelain around the center electrode looks like it has some deposits, it's alittle dirty. Nothing that I'm too worried about, I think.
I do use N2O so that's why I'm using the NGK TR6s. I just wanted to check to see if all my cylinders were running about the same in terms of AF. But I couldn't really see much difference, all I know is that they're all kind of whitish. I recently changed my fuel injectors, so I'm going to put new plugs in and take a look, but just concerned about the whiteness.
My AF is around 11.5-12.9 at WOT on the dyno.
So what do others have on their plugs? Could a few list what plug they use and the color? Maybe even a pic? I'd put a pic up of mine, but I lent my digital camera out to my gf.
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TECH Addict
Joined: Dec 2001
Posts: 2,298
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From: new england
Re: Spark plugs running lean, is this real? I ran stock plugs at first with head and cam done, plugs read very lean tannish color. Another thing to look for is center electrode not sitting centered in porcelain meaning it has been overheated and has warped to one side or the other. I replaced my oem plugs with GM Rapidfire #3 plugs. They visibly had shorter path to base of plug so i knew they were colder than stock even though Rapidfire doesnt have a official application for lS1, these worked beautifully!
Plugs read with slight tan on one side of porcelain and no soot buildup, from being too co0l or anything. I reccomend them.
Plugs read with slight tan on one side of porcelain and no soot buildup, from being too co0l or anything. I reccomend them.
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The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
Re: Spark plugs running lean, is this real? The A/F on AutoTAP always reads 14.7 as I understand it. That's a setting for the computer to determine desired A/F. Even when my car was at 17:1 it always read 14.7:1. Now on the Dyno it's 12.7:1 and it still reads 14.7:1. Thought I'd throw that at you so you are aware of it.
