Changed Plugs and now it backfires
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Registered User
Joined: Apr 2013
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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
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
TECH Enthusiast
Joined: Nov 2012
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From: NearHouston, TX
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.
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.
On The Tree
Joined: Nov 2012
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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.
