Jump to content

Did I Ruin My New Iridium Plugs?

jtupper

Recommended Posts

jtupper Enthusiast

jtupper

Posted
Posted

So I went down to O'Reilly last week and picked up some new plugs and plug wires. The guy behind the counter said the plugs were pre-set. I checked the gaps when I got home and they were set to 0.40 while the sticker under the hood said 0.60. I called the parts house and they said I should go by the sticker under the hood.

 

I have searched and found out that I should have left them at 0.40. The question is...did I ruin them by adjusting them?

 

My fuel economy has steadily decreased over the past few years. I'm getting about 11.5 mpg these days and I have been unable to figure out why. I replaced the original plugs with iridiums at about 100k (I currently have 161k) and set the gaps then to 0.60. I have noticed since then that economy has decreased over time. So, can I simply set the gaps back to 0.40 or am I about to be out another $60 for new plugs?

dlstewart01 Senior Enthusiast

dlstewart01

Posted
Posted

Service Information 2000 Chevrolet Chevy K Silverado - 4WD | Sierra, Silverado, Suburban, Tahoe, Yukon (VIN C/K) Service Manual | Document ID: 1903277

--------------------------------------------------------------------------------

 

#03-06-04-060A: Information on New Spark Plugs and Gapping - (Feb 12, 2007)

 

 

Subject: Information on New Spark Plugs and Gapping

 

 

Models: 2004 Buick Rainier

 

2002-2004 Cadillac Escalade, Escalade EXT

 

2003-2004 Cadillac Escalade ESV

 

2004 Cadillac CTS-V

 

1997-2004 Chevrolet Corvette

 

1998-2002 Chevrolet Camaro

 

1999-2004 Chevrolet Silverado

 

2000-2004 Chevrolet Suburban, Tahoe

 

2002-2004 Chevrolet Avalanche

 

2003-2004 Chevrolet Express, TrailBlazer

 

1999-2004 GMC Sierra

 

2000-2004 GMC Yukon, Yukon XL

 

2001-2004 GMC Yukon Denali, Yukon XL Denali

 

2002-2004 GMC Sierra Denali

 

2003-2004 GMC Envoy XL

 

1998-2002 Pontiac Firebird

 

2004 Pontiac GTO

 

2003-2004 HUMMER H2

 

with 4.8L, 5.3L, 5.7L or 6.0L V-8 Engine (VINs V, P, T, Z, G, S, N, U -- RPOs LR4, LM4, LM7, L59, LS1, LS6, LQ9, LQ4)

 

 

 

Attention: Please disregard the Set Gap Per Vehicle Specification statement on the side of an ACDelco® Iridium Spark Plug Box. The statement will be removed from the boxes in the future.

 

 

 

--------------------------------------------------------------------------------

 

This bulletin is being revised to bring attention to the Set Gap Per Vehicle Specification on the ACDelco® Iridium Spark Plug Boxes. Please discard Corporate Bulletin Number 03-06-04-060 (Section 06 -- Engine/Propulsion System).

 

 

--------------------------------------------------------------------------------

 

• A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed.

 

• The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 in) when the spark plug is made.

 

Notice: The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

 

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

 

 

© 2008 General Motors Corporation. All rights reserved.

Wires Enthusiast

Wires

Posted
Posted
So I went down to O'Reilly last week and picked up some new plugs and plug wires. The guy behind the counter said the plugs were pre-set. I checked the gaps when I got home and they were set to 0.40 while the sticker under the hood said 0.60. I called the parts house and they said I should go by the sticker under the hood.

 

I have searched and found out that I should have left them at 0.40. The question is...did I ruin them by adjusting them?

 

My fuel economy has steadily decreased over the past few years. I'm getting about 11.5 mpg these days and I have been unable to figure out why. I replaced the original plugs with iridiums at about 100k (I currently have 161k) and set the gaps then to 0.60. I have noticed since then that economy has decreased over time. So, can I simply set the gaps back to 0.40 or am I about to be out another $60 for new plugs?

 

A lot of times you can damage that fragile center electrode by gapping them (by banging it with the gapping tool). You can pull them out and look at them. If the center electrode is fine, just regap them at 0.040".

plumber802 Enthusiast

plumber802

Posted
Posted
So I went down to O'Reilly last week and picked up some new plugs and plug wires. The guy behind the counter said the plugs were pre-set. I checked the gaps when I got home and they were set to 0.40 while the sticker under the hood said 0.60. I called the parts house and they said I should go by the sticker under the hood.

 

I have searched and found out that I should have left them at 0.40. The question is...did I ruin them by adjusting them?

 

My fuel economy has steadily decreased over the past few years. I'm getting about 11.5 mpg these days and I have been unable to figure out why. I replaced the original plugs with iridiums at about 100k (I currently have 161k) and set the gaps then to 0.60. I have noticed since then that economy has decreased over time. So, can I simply set the gaps back to 0.40 or am I about to be out another $60 for new plugs?

 

A lot of times you can damage that fragile center electrode by gapping them (by banging it with the gapping tool). You can pull them out and look at them. If the center electrode is fine, just regap them at 0.040".

 

 

 

Yes.I agree.You should be able to pull them and CAREFULLY set the correct gap.

pistonslap Enthusiast

pistonslap

Posted
Posted

I also screwed up and gapped a couple of iridium plugs before i found out not to.I read in some forum that if you gap them you can remove some of the iridium off of the plug and that they will not last nearly as long. I left mine as is after i corrected the gap on the two plugs.Were your plugs showing any signs of wear?

jtupper Enthusiast

jtupper

Posted
  • Author
Posted

I thought about calling O'Reilly to see if they will swap them out, but I couldn't even tell you who I talked to. Probably my word against theirs.

 

The plugs I pulled out had quite a bit of carbon on them, certainly more than the originals I pulled out with almost double the mileage on them. I will try to post a pic of one later. I know I chewed up my gap tool pretty good setting the gaps, so I'm pretty sure that iridium tip is toast. Oh well, live and learn I guess...

-JMC- New Member

-JMC-

Posted
Posted

Josh,

Bring them back to us and I will get them swapped out for ya.

 

 

I thought about calling O'Reilly to see if they will swap them out, but I couldn't even tell you who I talked to. Probably my word against theirs.

 

The plugs I pulled out had quite a bit of carbon on them, certainly more than the originals I pulled out with almost double the mileage on them. I will try to post a pic of one later. I know I chewed up my gap tool pretty good setting the gaps, so I'm pretty sure that iridium tip is toast. Oh well, live and learn I guess...

jtupper Enthusiast

jtupper

Posted
  • Author
Posted
Josh,

Bring them back to us and I will get them swapped out for ya.

 

While I certainly appreciate your effort here, I was actually referring to O'Reilly Auto Parts. They are an auto parts chain here in Texas. :thumbs:

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • richard wysong
      Wow I'm in a pickle. (Broke down truck) and a story.

      By richard wysong · Posted

      You could try a used 1, they used that engine in the Astro vans, Plenty of them in the boneyard. Look for a wrecked or rotted 1 so the chance that it was scrapped for that reason and not a mechanical issue will be greater
    • KARNUT
      Wow I'm in a pickle. (Broke down truck) and a story.

      By KARNUT · Posted

      Google converting 98 4.3 spider injection to carburetor if all else fails. 
    • Hoginedgewood
      MPG Surprise

      By Hoginedgewood · Posted

      That computer lies!
    • Tbhats2130
      2018 Silverado Console USB Port Not Working

      By Tbhats2130 · Posted

      My centre console USB ports haven’t been working and the one in the glovebox is starting to act up. When I plug my phone into the cord the radio will go black and stop playing, and the CarPlay is inconsistent.   I checked the fuses and they were fine. I changed the USB port out and still nothing. Hoping for some advice on what I should be looking at.  
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      The truck is a 1995 Chevrolet S10 Blazer, 4.3 VIN "W" engine. :cracks knuckles:   On a whim - because I needed a headache - this truck was for sale so I stopped to take a look. Doesn't run. Well, it does, but barely. Long crank, choppy idle, bad misfire(s), it REEKS of fuel. I can DO this..I'm thinking. Diamond in the rough. One owner until last year. A young guy is selling it, he bought it 6 months ago. It stranded him more than once, he's got a newborn. It was in the shop 10 days ago and he "thinks" they said it needs a new fuel injection system. He can't put any more money into it, needs it gone. I was thinking of upgrading my Macbook, which is a total want, not a need. For less than the price of a new laptop I can have fun for months tinkering on this truck and enjoying it. I'm taking this truck home. The guy was beyond thrilled, his wife was there, she thanked me profusely, I could tell they were hurting. They seemed like good people in a bind.   Some parts, a wash, maybe a set of tires, and I can have a few months of fun and then turn it for beer money (or the next project).   Sure enough, there's a work order from a shop last week in the INCHES of paperwork on this truck dating back to when the first owner bought it. They put a new distributor in it, fuel injection work describes basically opening the plenum and putting it back together. He said he couldn't afford any more work so he had them button it up and that's when he put it up for sale.   I'm not well versed in 4.3. I did discover 1995 uses the 1992-1995 SCPI "Spider" injector which is riddled with issues from splitting lines, clogged or cracked poppet valves and plastic spider legs that crumble over time. Cool. I'll just order me a ne---. Oh, the auto parts store doesn't have it? Rock Auto doesn't have it. eBay? $$$$$$ for used. These are UNAVAILABLE period end of story unless you know "a guy" who's still got one in a box somewhere.   Can't upgrade to the '96-'04 injector, it's a different plenum, wiring/pinout and sensor config.   There are a few kinda "know a guy" -guy rebuild services for these injectors out there for about $350. Okay, Okay... I'd like to know if anyone has used them? Anyone got a lead on these crappy 92-95 spiders?   I also don't want to send MY spider to Narnia and back without knowing if that's truly the problem. I guess I'll need to pull apart the plenum and do some digging.   I was also thrown for a loop. This 1995 model year truck has an OBD-II connector. The interface is decidedly not OBD-II. I can read and reset trouble codes and view live data, but there's not a lot of data. Like misfire count and on what cylinder, that's not there. It's OBD-1.5.   Nothing is ever easy. Now it makes sense why this guy wanted to disappear this thing for cheap. I'm guessing the shop told him the injector is toast, the part is unobtainable and they're not going to sort sending the thing to a rando offering rebuild service on craigslist, and the kid likely can't be without a working car for 3 weeks even if they'd facilitate that.   Experience with these early SCPI's? Stories? Things to check? Sympathy? (..Nah...)   This can sit until I sort it. But I haven't had a problem with a vehicle I couldn't easily solve in a long time.    

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...