Rate my plugs..
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Joined: Aug 2016
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From: Boca Raton Florida
Rate my plugs..
Spark plugs from '04 C5 LS1 w/73k mi. Using this engine as replacement. Changing plugs/wires before putting in car.
I'm going with carbon deposits, ...looking in the cylinders I see deposits in center of several pistons, cleaner on periphery. Looks like original plugs and wires from condition.
All 8 look pretty consistent.
No experience with LS1's before so any input appreciated.
Thanks!
Last edited by pgandy; Sep 18, 2016 at 08:43 PM.
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They don't look bad for 73K miles.
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Maybe just a tad rich, but otherwise OK. Measure the gap and if it's .060 (or thereabouts), that's a good sign they MAY be the OE plugs. The current recommended gap is .040, but I don't recall if GM had made that gap change by the time the '04s had come out or not.
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I agree that they look a bit on the rich side, but fairly clean, nonetheless. If the car had 73K on them, as well as the plug wires, and maybe a dirty air filter on top of it, they look pretty normal.
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From: Boca Raton Florida
Interesting, may be my technique, since I'm replacing anyway, but two of the wires broke easily at the plug tube when pulling off using the tube. Should've removed from the coil first.
Thanks again, good feedback. I was also thinking a little rich.
Last edited by pgandy; Sep 19, 2016 at 12:10 PM.
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From: Dear Karma, I have a list of people you missed.
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Thanks all. Yes, the info I have is 0.060 for 2000 and earlier, 0.040 for 2001 and later. The new 41-110's came out of the box at 0.040 spot on.
Interesting, may be my technique, since I'm replacing anyway, but two of the wires broke easily at the plug tube when pulling off using the tube. Should've removed from the coil first.
Thanks again, good feedback. I was also thinking a little rich.
Interesting, may be my technique, since I'm replacing anyway, but two of the wires broke easily at the plug tube when pulling off using the tube. Should've removed from the coil first.
Thanks again, good feedback. I was also thinking a little rich.
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From: Anthony TX
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St. Jude Donor '08
I AGREE! 
I would replace the Plug Wires with the GM Performance Red Wires!
I would also check the O2 sensor outputs and make sure that they are properly cycling high to low/ low to high during the close loop cycle.
All GM LS1/6s are a little RICH with the factory tune. You can examine your Long Term Fuel Trims (LTFTs) and see if the PCM is adding or subtracting fuel which would mean you need to fix the issue causing that.. LTFT should be very close to 0%
BC
I would replace the Plug Wires with the GM Performance Red Wires! I would also check the O2 sensor outputs and make sure that they are properly cycling high to low/ low to high during the close loop cycle.
All GM LS1/6s are a little RICH with the factory tune. You can examine your Long Term Fuel Trims (LTFTs) and see if the PCM is adding or subtracting fuel which would mean you need to fix the issue causing that.. LTFT should be very close to 0%
BC
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From: Boca Raton Florida
Thanks. GM/Reds are what I have coming. When the engine goes in it will be seeing a different PCM and set of O2 sensors (originals before old engine was removed) but will monitor nonetheless.
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St. Jude Donor '13-'14-'15
Ok I am an old school tuner before computers however reading a plug has no bearing if the car is computer controlled or has a carb and distributor
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Ok I am an old school tuner before computers however reading a plug has no bearing if the car is computer controlled or has a carb and distributor
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
BC
Drifting
Joined: Jan 2015
Posts: 1,256
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From: Pennsylvania
Ok I am an old school tuner before computers however reading a plug has no bearing if the car is computer controlled or has a carb and distributor
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
Reading your plugs I see-----
Ideally you want the color change to happen on the "bend of the strap" Yours happens way past the bend and closer to the threads---
The closer you are toward the threads means you have "TOO MUCH TIMIMG"
If the color change was on the FLAT of the strap it would mean you don't have enough timing
The color change spot on the strap indicate timing------
Rich or lean fueling can be read by seeing how far down the color is on the porcelain
If the color on the porcelain is above more than 1/4 " then it is too rich If the color on the porcelain in less than 1/4" it is too lean( your photos did not show this)
My opinion from what I see------you have too much timing--------Remember these engines don't like a lot of timing even with premium fuel --My LS1's always ran best with only about 22-26* of timing at WOT
Sent you a pm. Thanks for the information