General Maintenance & Repairs Leaks | Squeaks | Clunks | Rattles | Grinds

Changed Plugs and now it backfires

Old 04-06-2013, 08:33 PM
  #1  
Registered User
Thread Starter
 
sircampsalot2's Avatar
 
Join Date: Apr 2013
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default Changed Plugs and now it backfires

Hello all I'm new to the forum, a friend over at Corvetteforum told me i may get more info when it comes to my engine on this forum so i thought i'd throw this out there and see if any of the engine Gurus might be able and willing to help me out with a problem.
I installed new spark plugs today (NGKR V-power) and it Idles fine...no miss or anything like that. It runs fine until i go WOT and then o get a strong smell of Carbon and it sounds like its backfiring through the tail pipe. little short hesitations.I have a friend that is going through mechanic school and he took a ride with me and said he thinks that its just blowing carbon off the piston tops and valves....Someone else said i gapped the plugs to wide. I gapped them at .60 which is what it says on the fenderwell of the car to gap plugs at. I'm not sure what to do now...It was running fine before i changed the plugs and the old plugs looked fine i just didnt know how many miles were on them since i just bought the car and decided to change them. Any ideas? thanks guys
Old 04-06-2013, 08:42 PM
  #2  
TECH Enthusiast
 
RJDio's Avatar
 
Join Date: Nov 2012
Location: NearHouston, TX
Posts: 555
Likes: 0
Received 0 Likes on 0 Posts
Default

I've been told that the NGK Iridium TR51X (that is what I use and they are pre-gapped at the factory) are gapped at .40. I have a Naturally aspsirated LS1 and I did some research before I bought plugs and that plug and gap was recommended by several people that know their stuff.

Because the tip is supposed to be fragile, I didn't even check them or gap them, I took them out of box and installed and the LS1 loves them.
Old 04-06-2013, 09:04 PM
  #3  
Registered User
Thread Starter
 
sircampsalot2's Avatar
 
Join Date: Apr 2013
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default

Ok Rj thanks yes they were gapped at .40 out of the box, I guess i need to regap them around .40 to .50 thanks i appreciate the reply man
Old 04-07-2013, 07:46 AM
  #4  
12 Second Club
iTrader: (2)
 
murphinator's Avatar
 
Join Date: Sep 2009
Location: southern Maine
Posts: 1,650
Likes: 0
Received 1 Like on 1 Post

Default

maybe you cracked the porcelain on a plug or 2 installing them ? you wouldnt be the first one to do that....
Old 04-07-2013, 07:53 AM
  #5  
On The Tree
 
birner88's Avatar
 
Join Date: Nov 2012
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default

I also run the ngk plugs and have read an article somewhere about gm changing the plug gap and saying the .40 was correct. Havent had any problems with missing or backfiring. Except once after I installed my headers I accidently tapd the plug when sliding driver side in. Swapped the plug and was good to go.


Thread Tools
Search this Thread
Quick Reply: Changed Plugs and now it backfires



All times are GMT -5. The time now is 12:49 PM.