horrid mileage after header install
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From: San Marcos, TX
horrid mileage after header install Hey guys, I installed headers and have yet to get it tuned. Its got 10 SES codes, the No activity on the rear o2s, the AIR, and EGR. Its thrown each twice. I have an actron scanner so I can pull pcm values like lt ftrm and o2 voltages and all that good stuff. Any idea if these codes are causing the mileage? I mean I sat in the car an idled for like 20 min and the needle moved a bit. I am waiting for a tuner to give me a call to delete the codes, but can this be related (and im praying it is) to the header install and cat delete? Any values I can pull to determine if everything is in order?
TIA,
John
EDIT:
TIA,
John
EDIT:
Code:
Here is the scan data (not synchronized, I had to write it all out by hand)
This is all idling
Abslt TPS (%) .8,.4
ENGINE RPM 790,803,813,800,796
CALC LOAD (%) 2.0,2.0
MAF (LB/M) .87,.88
MAP ("HG) 8.9, 8.6
COOLANT (*F) 83
IAT (*F) 95,97
IGN ADV (DEG) 21.5,22.21.5,22.5
SECONDARY AIR ATMOS
LT FTRM1 1.6
ST FTRM1 -1.6,-2.3,-.8,3.1
LT FTRM2 0.0
ST FTRM2 0.0,1.6,0.0,.8
ST FTRM11 -1.6,-3.9,-2.3,0.0,-2.3
ST FTRM21 0.0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 .110,.145,.560,.825,.100
O2S12 .445,.450
O2S21 .100,.650,.700,.225,.810
O2S22 .440,.445 Last edited by 2KThunder; Sep 1, 2006 at 10:57 PM.
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From: Lake Zurich, IL
what are the exact codes... you probably have a wire that melted through the headers and is causing you to go into open loop....
Check "Engine Sensor" Fuse... but until you post all the codes it's just guess work
Check "Engine Sensor" Fuse... but until you post all the codes it's just guess work
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From: Philly
did you make O2 extentions or tune out the rears? i remember there was a guy on this site that hooked his O2's up wrong. he put one front and one rear O2 into his two front O2 bungs and was burning a quarter tank of gas letting it idle for 30 mins! he switched his O2's around and it completely went away.
my money's on you hooked up your O2's incorrectly.
my money's on you hooked up your O2's incorrectly.
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Yeah I bought extensions. Wait a sec... You mean the sensors themselves are different? Or just where he hooked them up? I DID NOT mark the sensors, and the rears have not been tuned out, They are sitting empty.
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From: Philly
yes, you should have marked your sensors. i bet they're hooked up wrong 
swap them around. a guy had a rear O2 in the front O2 bunghole (haha, i said bunghole 
) and his gas mileage DIED.
hopefully you still have all 4 O2's. i believe you should see that 2 O2's have longer wires than the other two. put the two with the longer wires up front. if i turn out to be wrong, mix and match until the problem's fixed.
the rears siting empty will not affect gas mileage. you'll just throw codes.
swap them around. a guy had a rear O2 in the front O2 bunghole (haha, i said bunghole ) and his gas mileage DIED.hopefully you still have all 4 O2's. i believe you should see that 2 O2's have longer wires than the other two. put the two with the longer wires up front. if i turn out to be wrong, mix and match until the problem's fixed.
the rears siting empty will not affect gas mileage. you'll just throw codes.
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Originally Posted by ChocoTaco369
did you make O2 extentions or tune out the rears? i remember there was a guy on this site that hooked his O2's up wrong. he put one front and one rear O2 into his two front O2 bungs and was burning a quarter tank of gas letting it idle for 30 mins! he switched his O2's around and it completely went away.
my money's on you hooked up your O2's incorrectly.
my money's on you hooked up your O2's incorrectly.
almost like 95% of these cases after header installs is o2 sensors were hooked up wrong and the gas mileage drops tremendously. LS1 Tech Stories
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From: San Marcos, TX
Originally Posted by slow
Front and rear O2 sensors on these cars are the same, so they can interchange without issues.
Ryan
Ryan
Will the voltages they are getting at idle help any in diagnosing?
Last edited by 2KThunder; Sep 1, 2006 at 12:25 PM.
yes, if they switch, then they should be good, if they are lazy, then it will be bad and cause that to run rich.
Post cat O2's, if lazy will not throw a ses light, as that is the expected result after proper functioning cats.
Ryan
Post cat O2's, if lazy will not throw a ses light, as that is the expected result after proper functioning cats.
Ryan
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Ok thanks. So would pulling the voltages at idle be able to tell me if they are being lazy? I havent figured out how to store my own data with the scan tool, which is why I am only able to offer idle data 
Thanks for all the help so far
Thanks for all the help so far Tech Resident
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From: Philly
just try switching them around. trust me on this one, i've seen this exact same situation play out. for some reason, he had a rear O2 up front and his mileage died. he realized two O2's had wires shorter than other two. he had a long one and a short one up front. he pulled the short one and put both long ones up front. it was then fixed.
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i will I looked, ive got one long one and one short one up front lol. Here is the scan data (not synchronized, I had to write it all out by hand)
This is all idling
Abslt TPS (%) .8,.4
ENGINE RPM 790,803,813,800,796
CALC LOAD (%) 2.0,2.0
MAF (LB/M) .87,.88
MAP ("HG) 8.9, 8.6
COOLANT (*F) 83
IAT (*F) 95,97
IGN ADV (DEG) 21.5,22.21.5,22.5
SECONDARY AIR ATMOS
LT FTRM1 1.6
ST FTRM1 -1.6,-2.3,-.8,3.1
LT FTRM2 0.0
ST FTRM2 0.0,1.6,0.0,.8
ST FTRM11 -1.6,-3.9,-2.3,0.0,-2.3
ST FTRM21 0.0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 .110,.145,.560,.825,.100
O2S12 .445,.450
O2S21 .100,.650,.700,.225,.810
O2S22 .440,.445
This is all idling
Abslt TPS (%) .8,.4
ENGINE RPM 790,803,813,800,796
CALC LOAD (%) 2.0,2.0
MAF (LB/M) .87,.88
MAP ("HG) 8.9, 8.6
COOLANT (*F) 83
IAT (*F) 95,97
IGN ADV (DEG) 21.5,22.21.5,22.5
SECONDARY AIR ATMOS
LT FTRM1 1.6
ST FTRM1 -1.6,-2.3,-.8,3.1
LT FTRM2 0.0
ST FTRM2 0.0,1.6,0.0,.8
ST FTRM11 -1.6,-3.9,-2.3,0.0,-2.3
ST FTRM21 0.0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 .110,.145,.560,.825,.100
O2S12 .445,.450
O2S21 .100,.650,.700,.225,.810
O2S22 .440,.445
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From: Philly
Originally Posted by 2KThunder
Anyone? Notice anything wrong with those numbers?
just put both long ones up front. i figured you'd have a long and a short
There is no difference in the O2 sensors other than wire length on some of them. Any of them will work in any position if the wires reach and the sensors are good. Your data looks like your front O2s are switching OK.
COOLANT (*F) 83
This from your log stands out as a problem if the car had been running for a while especially since your IATs are IAT (*F) 95,97. If the car was fully warned up, or had been running for awhile, check your coolant temp sensor. They sometimes get damaged or bumped durring a header install.
COOLANT (*F) 83
This from your log stands out as a problem if the car had been running for a while especially since your IATs are IAT (*F) 95,97. If the car was fully warned up, or had been running for awhile, check your coolant temp sensor. They sometimes get damaged or bumped durring a header install.
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From: Texas
What kind of new wires did you get? What kind of plugs? Do you have your old wires? I know you didn't say it was missing but I just want to see what happens when you put old wires back on. Oh and did you check for any burned through wires as stated before???
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Ive actually got cheap autolite plugs, I wasnt planing on swapping the Densos, but broke one so I switched them. Ive got MSD wires, they actually went onto the car while it was already getting bad milage. None are burned through. I am gonna order some TR55s just for completeness. Im actually gonna do that right now. Ill get an actual MPG for you all, and maybe a Datalog if my friend with autotap comes into town.
