Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Read my plugs

Thread Tools
 
Search this Thread
 
Old Jun 14, 2006 | 10:42 PM
  #1  
618HAWK's Avatar
Thread Starter
TECH Fanatic
iTrader: (361)
 
Joined: Aug 2004
Posts: 1,704
Likes: 2
From: Lomita CA
Default Read my plugs

Can some please shed a bit of light on these plugs. Getting a flashing SES light and #5 showed the most misfires. Only at cruise when in 5th & 6th. I know the picture is not the best but the darker plug is from # 5. I also pulled the #1 plug for comparison. As you can see #1 is clean and white and #5 is dark and brown.

These are new plugs with on a 100-150 miles on them. So with that I can see why #1 is so clean and nice. Next is a compression check for #5, to see if I have a problem there.


With the excessive brown on the insulator, I am thinking I might have damaged a ring gland, and now getting a bit (blow by) of oil in the cylinder.

Note: had a 1/4 inch of oil in my catch can after the 100-150 miles, can was empty-ed and cleaned when all plugs were replaced.

My A/F is about 11.8-12.0 @ WOT So I am sure it is not a lean condition.



Last edited by 618HAWK; Jun 15, 2006 at 12:08 AM.
Reply
Old Jun 15, 2006 | 12:52 AM
  #2  
ArcticZ28's Avatar
TECH Senior Member
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (14)
 
Joined: Jun 2004
Posts: 5,125
Likes: 4
From: Alexandria, VA
Default

Kinda stating the obvious, but could #5 be incorrectly gapped? I would check that, as well as the compression test to see if you're getting blow-by, check the wire to #5 to see that it's not damaged... could be things that aren't so major as damaged ringlands.
Reply
Old Jun 15, 2006 | 12:55 AM
  #3  
94lt4's Avatar
Teching In
 
Joined: Sep 2005
Posts: 24
Likes: 0
Default

I had a bad injector so the same thing to #3 for me, it cut in and out. I manage to find it with the help of a tech 1. It drove me nuts for a week. Good luck.

Rob
Reply
Old Jun 15, 2006 | 01:05 AM
  #4  
618HAWK's Avatar
Thread Starter
TECH Fanatic
iTrader: (361)
 
Joined: Aug 2004
Posts: 1,704
Likes: 2
From: Lomita CA
Default

Originally Posted by ArcticZ28
Kinda stating the obvious, but could #5 be incorrectly gapped? I would check that, as well as the compression test to see if you're getting blow-by, check the wire to #5 to see that it's not damaged... could be things that aren't so major as damaged ringlands.
I hope, swapped over the wire and coil to another cylinder going to to do a Auto Tap run tomorrow.

I thought of a injector as well, but I don't think that would be the cause of the dark brown color would it. Looks like oil, but might swap a injector as well if the Auto Tap Run dose not point to any thing.

Gaps are right on,,,
Reply
Old Jun 15, 2006 | 01:30 AM
  #5  
CAT3's Avatar
Restricted User
iTrader: (9)
 
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Default

#1 looks lean, bleached white porcelain. Both have carbon deposits on the facing of the plug (the flat portion on the end of the threads). Almost looks like you have a timing mark about to show on #1 (the line of color change on the grounding strap), but cant really tell from being so faint.
I recommend you put the plugs in, check it with your Tech. Then taking your camera with you, go do a WOT BLAST, pull thru as long as you can "legally" and safely, a good two three will work. As soon as you get off the WOT, shut the car down, pull the plugs and snap a picture, try to do a macro from the mid-threaded portion up. A nice side shot and a front (holding it so the grounding strap can be seen with the "gap" to one side or another, and for the front use a slight 20* angle looking down at the porcelain with the gap facing you). The WOT blast is necessary for a fueling and timing reading, as well as when you let off if you coast with the engine on it will "wash" away any deposits, timing marks etc.. I will try to remember to check back here, via subscribe, but if you post and I dont catch it in 30min pm me please. Thanks and GL

Charlie
Reply
Old Jun 17, 2006 | 12:25 PM
  #6  
CAT3's Avatar
Restricted User
iTrader: (9)
 
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Default

Any updates?
Reply
Old Jun 17, 2006 | 02:19 PM
  #7  
618HAWK's Avatar
Thread Starter
TECH Fanatic
iTrader: (361)
 
Joined: Aug 2004
Posts: 1,704
Likes: 2
From: Lomita CA
Default

No not yet, but you will be the 1st to know pic,s PM ect. THANKS for your input-concern.

Chris
Reply
Old Jun 24, 2006 | 10:54 PM
  #8  
618HAWK's Avatar
Thread Starter
TECH Fanatic
iTrader: (361)
 
Joined: Aug 2004
Posts: 1,704
Likes: 2
From: Lomita CA
Default

Well as luck would have it. After swapping plugs, coil, wire. Still had misfire on #5. Preformed a compression check and my thoughts were confirmed. 65psi. 1,3,7 were 150-160. Did not even bother to look at the Rh side.

I new it was only a matter of time, but did not think it would have happened so soon.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Jun 25, 2006 | 05:43 AM
  #9  
ezrollin's Avatar
Launching!
 
Joined: Dec 2005
Posts: 207
Likes: 0
Default

so now its time to get a leak down tester and see what it really turns out to be.
or you could do the "wet" compression test
my lowest compression reading was 80psi
Reply




All times are GMT -5. The time now is 08:51 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE