Notices
GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |

Open Headers?

Thread Tools
 
Search this Thread
 
Old 06-07-2005, 10:51 PM
  #11  
TECH Senior Member
iTrader: (1)
 
Flyer's Avatar
 
Join Date: Jan 2003
Location: Armpit of East TX
Posts: 9,342
Likes: 0
Received 0 Likes on 0 Posts
Default

The o2's need to be unplugged to keep them from telling the PCM its running rich. Fresh air gets on the o2's and fools the compter into thinking its running lean, so it starts dumping lots of fuel. You'll foul out a set of plugs quick.
Old 06-08-2005, 12:38 AM
  #12  
On The Tree
Thread Starter
iTrader: (1)
 
Bullhead00's Avatar
 
Join Date: Feb 2005
Location: Gainesville, FL
Posts: 128
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Flyer
The o2's need to be unplugged to keep them from telling the PCM its running rich. Fresh air gets on the o2's and fools the compter into thinking its running lean, so it starts dumping lots of fuel. You'll foul out a set of plugs quick.
Okay, I understand the part about the fresh air hitting the o2's and making the computer think it's running lean and dumping the fuel in to compensate. But wouldn't unplugging them make this even worse? What will happen when I unplug the o2's?
Old 06-08-2005, 12:58 AM
  #13  
TECH Senior Member
iTrader: (1)
 
Flyer's Avatar
 
Join Date: Jan 2003
Location: Armpit of East TX
Posts: 9,342
Likes: 0
Received 0 Likes on 0 Posts
Default

The o2's don't register anything, the PCM thinks they are showing a neutral .500 so they make no adjustments to the fuel trims. The PCM will consider them broke after so long, but it takes a while. Since the o2's are showing a dead nuts neutral, it makes no adjustments to the fuel trims.
Old 06-08-2005, 01:23 AM
  #14  
On The Tree
 
Black_Silverado_5.3's Avatar
 
Join Date: Jan 2005
Location: Edinburg, Tx.
Posts: 118
Likes: 0
Received 0 Likes on 0 Posts
Default

I drove my truck 15miles on open headers to the nearest muffler shop. The truck wasn't smoking at first, but once i got to the city, it started smokin bad . I had a blast watching the expressions on people's faces when i'd rev the truck at a stop light It was loud as hell, and since i had my windows open, the cabin smelled of exhaust for about a day or so then it went away. I had my O2 sensors on at the time and the truck still smoked. I'd say go for it, I had the same question about mine until someone posted that they ran their truck for two weeks on open headers ...Let us know what happens

Good luck and enjoy the ride

SLA
Old 06-08-2005, 05:55 PM
  #15  
On The Tree
Thread Starter
iTrader: (1)
 
Bullhead00's Avatar
 
Join Date: Feb 2005
Location: Gainesville, FL
Posts: 128
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Black_Silverado_5.3
I drove my truck 15miles on open headers to the nearest muffler shop. The truck wasn't smoking at first, but once i got to the city, it started smokin bad . I had a blast watching the expressions on people's faces when i'd rev the truck at a stop light It was loud as hell, and since i had my windows open, the cabin smelled of exhaust for about a day or so then it went away. I had my O2 sensors on at the time and the truck still smoked. I'd say go for it, I had the same question about mine until someone posted that they ran their truck for two weeks on open headers ...Let us know what happens

Good luck and enjoy the ride

SLA
That's funny. I wonder why it was smoking? Flyer, maybe you could clear this up?
Old 06-08-2005, 06:02 PM
  #16  
11 Second Club
 
Texas Terminator's Avatar
 
Join Date: Jul 2002
Location: Beaver Falls, PA
Posts: 1,424
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Flyer
The o2's need to be unplugged to keep them from telling the PCM its running rich. Fresh air gets on the o2's and fools the compter into thinking its running lean, so it starts dumping lots of fuel. You'll foul out a set of plugs quick.
WHAT UP FLYER!?!

OR...........you can just leave them alone and make up some short extensions until you get your exhaust on, worked for me.
Old 06-08-2005, 06:07 PM
  #17  
On The Tree
Thread Starter
iTrader: (1)
 
Bullhead00's Avatar
 
Join Date: Feb 2005
Location: Gainesville, FL
Posts: 128
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Texas Terminator
WHAT UP FLYER!?!

OR...........you can just leave them alone and make up some short extensions until you get your exhaust on, worked for me.
How long would the pipe need to be and what would I need to fabricate the extensions?
Old 06-08-2005, 06:19 PM
  #18  
11 Second Club
 
Texas Terminator's Avatar
 
Join Date: Jul 2002
Location: Beaver Falls, PA
Posts: 1,424
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Bullhead00
How long would the pipe need to be and what would I need to fabricate the extensions?
not too long, mine were only about 6" or so. all you would need would be two collector flanges and some pipe welded on the back of them, then just bolt them up and off you go. oh yea, enjoy the sound and the looks you will get!!
Old 06-09-2005, 07:45 AM
  #19  
Banned
iTrader: (4)
 
litreddevil's Avatar
 
Join Date: Oct 2003
Location: From Houma La. Living n Ellisville Miss.
Posts: 5,151
Likes: 0
Received 1 Like on 1 Post
Default

I Have Drove My Truck For Weeks With Cutouts Open
Old 06-09-2005, 07:52 AM
  #20  
TECH Senior Member
iTrader: (1)
 
Flyer's Avatar
 
Join Date: Jan 2003
Location: Armpit of East TX
Posts: 9,342
Likes: 0
Received 0 Likes on 0 Posts
Default

Smoking after the trip is from the o2 getting fresh air across them. The exhaust pulses, on the pulses, fresh air is sucked back up into the collector and messes the readings up on the o2 sensors. It does this no matter how rich it's running, so the PCM ends up adding as much fuel as it can.

Extensions will work also, but they need to be closer to 12" or so.

Hey TT, been back to the track lately?


Quick Reply: Open Headers?



All times are GMT -5. The time now is 05:28 PM.