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Old 09-08-2008, 12:45 PM   #1
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Default Please read my plugs

Took them out yesterday after about 2000 boosted miles @ 7-9 psi. They are Autolite 3923's which cross-reference with NGK BKR6. Running at stock gap (0.8 mm), no misfires etc.

Pl help me understand whats going on in #4?? They don't seem to be aluminum deposits but I could be wrong. The electrodes arent melted either, it just seems to be some other crud that's on there.

Pic 1: L to R: #1 thru #4

Pic 2: close up of #4
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Old 09-08-2008, 12:51 PM   #2
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either oil contamination or det / pre ign damage
those other plugs look like they were running hot as well
thats my guess
lets see what braineack has to say
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Old 09-08-2008, 01:03 PM   #3
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Only way to get a good plug read is do a pull and shut the car off at the area you wish to read. (rpm wise). Normal driving will always run lean and hide other information.
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Old 09-08-2008, 01:14 PM   #4
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First thing I'd do is to throw away the Autolite Plugs. Then install NGK's and check back on them in a week.
And make sure that you have NGK "blue" plug wires on there also...
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Old 09-08-2008, 01:14 PM   #5
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I know they're hotter than required, I'm only concerned about the deposits on #4. There is no reason for those deposits to be there in any rpm range.

LOLA, finding NGK's here is close to impossible. I can throw on some 3922's (one colder range) though.
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Old 09-08-2008, 01:19 PM   #6
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There are 2 Advance Auto Parts stores listed in Westland, MI. They can get you any NGK plug you could ever want. They special order my NGK plugs because they never carry them, and they arrive to the store the next day without fail.
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Old 09-08-2008, 01:25 PM   #7
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Quote:
Originally Posted by Splitime View Post
Only way to get a good plug read is do a pull and shut the car off at the area you wish to read. (rpm wise). Normal driving will always run lean and hide other information.
+1 if you kill it at idle, you'll only know what it does at idle.

and second, why do you need to read plugs? modern cars have many ways to gather the same information (o2 sensor, knock sensor, egt)
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Old 09-08-2008, 01:35 PM   #8
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Originally Posted by 3barboost View Post
lets see what braineack has to say

doesn't look good. Is there oil on it?
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Old 09-08-2008, 01:37 PM   #9
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I'll take a guess... it's a combo of ash deposits and oil fouling.

"APPEARANCE: Ash deposits are characterized by light brown or white colored deposits crusted on the side or center electrodes. In some cases it may give the plug a rusty appearance.

CAUSE: Ash deposits are normally derived from oil or fuel additives burned during normal combustion. Normally they are harmless, though excessive amounts can cause misfiring. If deposits are excessive in short mileage, the valve guides may be worn."

http://www.classictruckshop.com/club...park/plugs.htm
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Old 09-08-2008, 03:25 PM   #10
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Quote:
Originally Posted by RotorNutFD3S View Post
There are 2 Advance Auto Parts stores listed in Westland, MI. They can get you any NGK plug you could ever want. They special order my NGK plugs because they never carry them, and they arrive to the store the next day without fail.
^I second that one^
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Old 09-08-2008, 04:42 PM   #11
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doesn't look good. Is there oil on it?
not really. just a whole lot of soot.

I haven't used any additives at all to cause the , only straight 93 octane since I was turbo'ed.


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+1 if you kill it at idle, you'll only know what it does at idle.

and second, why do you need to read plugs? modern cars have many ways to gather the same information (o2 sensor, knock sensor, egt)
the plug has no reason to look like that on an engine running normally, regardless of rpm.

and, plugs never lie, O2 sensors can lie specially if the engine's been burning oil.
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Old 09-08-2008, 04:49 PM   #12
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Wonder if you have an injector sticking open problem. Best to start with fresh plugs and wires and see how it goes from there.
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Old 09-08-2008, 04:54 PM   #13
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Am I seeing things or is that #4 electrode cracked? I am looking at the light colored portion at about 7 o'clock in the second image.

The rest of the plugs look lean to me.

+1 on getting a WBO2 sensor as a tuning tool.
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Old 09-08-2008, 05:04 PM   #14
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Maybe he needs a dual feed fuel rail?

and a manicure.
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Old 09-08-2008, 05:22 PM   #15
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Originally Posted by The_Pipefather View Post
not really. just a whole lot of soot.
The other three plugs do look a bit lean. If one injector is stuck open (making the plug sooty), and the ECU is running closed loop off of an O2 sensor, the ECU might see that as a reason to cut injector duration, making the rest of the cylinders run lean. Not knowing whether MSI Ver.3 works that way kind of makes this answer a crap shoot, but it's all I got.
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Old 09-08-2008, 06:59 PM   #16
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Quote:
Originally Posted by ZX-Tex View Post
Am I seeing things or is that #4 electrode cracked? I am looking at the light colored portion at about 7 o'clock in the second image.

The rest of the plugs look lean to me.

+1 on getting a WBO2 sensor as a tuning tool.
no its not cracked, just that a piece of deposit came off while inspecting the plug.

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Originally Posted by Thucydides View Post
The other three plugs do look a bit lean. If one injector is stuck open (making the plug sooty), and the ECU is running closed loop off of an O2 sensor, the ECU might see that as a reason to cut injector duration, making the rest of the cylinders run lean. Not knowing whether MSI Ver.3 works that way kind of makes this answer a crap shoot, but it's all I got.
I dont think the motor is running lean cause my LC1 shows 11.5 to 12 anywhere over 5 psi boost. I am running closed loop up to 110 kpa MAP.

But yeah, what you say might be a possibility, specially since my injectors are straight off the junkyard, not blueprinted.
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Old 09-08-2008, 07:11 PM   #17
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Quote:
Originally Posted by The_Pipefather View Post
But yeah, what you say might be a possibility, specially since my injectors are straight off the junkyard, not blueprinted.
Then you could swap injector positions with new plugs and see if the problem repeats itself in the new position. I admit it's a bit of a long shot, but stranger things have happened.

And besides; the deposits you see may not be happening under boost but at manifold pressures where you normally drive and where you're running closed loop. Under those circumstances a stuck injector is more likely to give you the symptoms you're seeing.
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Old 09-08-2008, 09:19 PM   #18
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Quote:
Originally Posted by y8s View Post
...why do you need to read plugs? modern cars have many ways to gather the same information (o2 sensor, knock sensor, egt)
None of those will alert you to a condition such as this one, from my car.

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Old 09-08-2008, 10:25 PM   #19
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None of those will alert you to a condition such as this one, from my car.

Yup; you'd need one of those sensors for each of the four cylinders. So Kotomile, what was the problem with your car?
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Old 09-09-2008, 12:07 AM   #20
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Some electrically fubarred injectors, most likely. It's parked 1700-some miles away from me, but it should be sorted by Christmas.
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