New Headers Backfire at Idle Help
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
New Headers Backfire at Idle Help
Just Installed LG Streets and Off Road X on 2002 ZO6
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
Tech Contributor
Joined: Jan 2007
Posts: 19,345
Likes: 1,123
From: Dyer, IN
Just Installed LG Streets and Off Road X on 2002 ZO6
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
Last edited by lucky131969; Aug 17, 2009 at 11:27 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,345
Likes: 1,123
From: Dyer, IN
Ok, so it sounds like the extra fuel is being introduced from the left bank, and you probably have an exhaust leak on that side, which is igniting the fuel in the pipe. How does it run otherwise? Smooth idle...?
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
My first first guess was exhaust making the O2 read lean pumping added fuel. The LT fuel trims are way off when I 1st start the car but into range right away
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
Tech Contributor
Joined: Jan 2007
Posts: 19,345
Likes: 1,123
From: Dyer, IN
Use a lit cigarette, incense, etc. around the exhaust connections while the car is running. If there is a leak, the smoke will be drawn in at the connection.
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
Just thinking I may have overlooked something else?
It's driving me up a wall.
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Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
Drifting
Joined: Feb 2006
Posts: 1,420
Likes: 0
From: Boston MA
Just Installed LG Streets and Off Road X on 2002 ZO6
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
I've installed about 6 sets of these with and without cats and never had this issue before.
Backfires at Idle and Low speeds.
Facts:
#1 Moved the rear O2s to the front
#2 The O2 sensors are NOT crossed
#3 Rear O2s Tuned out with HP Tuner
#4 Installed new plug wires.
Not Throwing any Codes
I pulled the plugs in extra bungs on the X-pipe. Pass side is nice and brown but the Driver side is black and sooty.
I did reuse the OEM Headers gaskets so at this point I can only think the is an exhaust leak that is causing the backfire.
The Chevy Dealer in town have only 1 lousy gasket between them
What do you guy think?
Thanks
Vega$Vette is online now Report Post Edit/Delete Message
Driver's side being black and sooty? Is this a burn in the headers, or can you remove the residue produced? If the latter, you may have an exhaust leak at that connection.
Also, I just noticed you reused the stock gaskets. Normally, you should always replace those. Get a new set of gaskets and see what happens there.
Drifting
Joined: Feb 2006
Posts: 1,420
Likes: 0
From: Boston MA
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
Replaced the driver side gasket. (Dealers only had 1 gasket in all of Las Vegas)
Running better bu still backfires it idle and after decel. New pass gasket here tomorrow.
Also thinking maybe the O2 Sensor? I'm getting high FT #s on Bank 2.
When I reset fuel trims it will run perfect at idle for 15 mins NO backfire. I rev it a little and then the BF starts up again and will continue until I hit the reset FT button.?
Running better bu still backfires it idle and after decel. New pass gasket here tomorrow.
Also thinking maybe the O2 Sensor? I'm getting high FT #s on Bank 2.
When I reset fuel trims it will run perfect at idle for 15 mins NO backfire. I rev it a little and then the BF starts up again and will continue until I hit the reset FT button.?
Tech Contributor
Joined: Jan 2007
Posts: 19,345
Likes: 1,123
From: Dyer, IN
Replaced the driver side gasket. (Dealers only had 1 gasket in all of Las Vegas)
Running better bu still backfires it idle and after decel. New pass gasket here tomorrow.
Also thinking maybe the O2 Sensor? I'm getting high FT #s on Bank 2.
When I reset fuel trims it will run perfect at idle for 15 mins NO backfire. I rev it a little and then the BF starts up again and will continue until I hit the reset FT button.?
Running better bu still backfires it idle and after decel. New pass gasket here tomorrow.
Also thinking maybe the O2 Sensor? I'm getting high FT #s on Bank 2.
When I reset fuel trims it will run perfect at idle for 15 mins NO backfire. I rev it a little and then the BF starts up again and will continue until I hit the reset FT button.?
Team Owner
Joined: May 2006
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From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
John,
Have you tried switching the plug wires from one side to the other? (Will eliminate the wire issue)
If not already check, follow the wires "TO" the O2 sensors and make sure they have "NOT" hit the headers and burned - I had this one day with some popping and it turned out to be the O2 wire against the header, and after years with the headers!
Also check to make sure there are no grounds that came loose during the install of the new headers, this seems to be a problem lately, grounds coming loose and causing all sorts of odd prob's
I am still at work till 7:30 pm this evening and I will check my computer later to see if anything else has happened!
Thanks,Matt
Have you tried switching the plug wires from one side to the other? (Will eliminate the wire issue)
If not already check, follow the wires "TO" the O2 sensors and make sure they have "NOT" hit the headers and burned - I had this one day with some popping and it turned out to be the O2 wire against the header, and after years with the headers!
Also check to make sure there are no grounds that came loose during the install of the new headers, this seems to be a problem lately, grounds coming loose and causing all sorts of odd prob's
I am still at work till 7:30 pm this evening and I will check my computer later to see if anything else has happened!
Thanks,Matt
Thread Starter
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
I put a new header gasket on driver side and still back fired (dealer
will have another one for me tomorrow) Then I data logged data and saw O2 reading high on B2 so while waiting for the header gasket I changed the o2 sensor. No help. Logged data again and I have nice smooth O2 lines on B1 and very jagged O2 lines on B2 so it has to be the gasket on the pass side.
will have another one for me tomorrow) Then I data logged data and saw O2 reading high on B2 so while waiting for the header gasket I changed the o2 sensor. No help. Logged data again and I have nice smooth O2 lines on B1 and very jagged O2 lines on B2 so it has to be the gasket on the pass side.
