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GMFS Senior OG Member
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Discussion Starter #1
I've just insalled my headers on my 95 C1500 305. Now the truck idles roughly, and it isn't loud at all mater of fact it seems less noisy.. I go to check out the spark plugs to see if I might of screwed them up..

Any sugestions you guys might have will be really helpful..
TIA!!
 

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03 Tahoe
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1,364 Posts
Headers alone (depending on brand) can quite exhuast note since ideally they are designed to equalize exhaust pulses. If this is done that exhaust note can be quieter. As far as the rough idle did you need to relocate or mess around with the 02 sensor at all? I had to on my old 94 when I did a header install and it went out on me. Otherwise just retorque all the header bolts, make sure all the flanges are snug/equally torqued, and finally make sure the plug wires aren't burned/touching the header tubes/properly secure to the spark plugs.

Cameron
 

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internet bigot®
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4,016 Posts
you'll definetly need to retorque bolts... after about a month, i would take em' back out and then put torque seal on em.. after theyve broken in enough.
 

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GMFS Senior OG Member
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Discussion Starter #4
Yeah I just retorqued the header bolts (man they were loose) spark plugs are ok (left them in while installing the headers), firing order ok (just changed wires). But I think I screw up the 02 sensor when I hollowed out the cat (I know that's illegal) I'm going to check it out later. It's running a little bit better. This is the first time I've ever installed a set of headers on a electronic motor.
 

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My name's not Kevin
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308 Posts
How does it run off idle? If it's ok then your plugs and wires should be fine. It will also take your computer a while to "readjust" to the changes you made. It took mine about a week. I would check the O2 though.
 

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GMFS Senior OG Member
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Discussion Starter #6
kevindepot said:
How does it run off idle? If it's ok then your plugs and wires should be fine. It will also take your computer a while to "readjust" to the changes you made. It took mine about a week. I would check the O2 though.
It idles fine but when you take off it's really rough than it smooths out at 50 mph. I through my snap-on scanner on and it comes up with a lean condition. (damm electronic motors :evillol:) If the 02 sensor was bad it would call out a rich condition? I didn't know it will take awhile for the computer to "readjust"?
 

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I had a lean condition once because the MAF was not on good on a previous truck. Check anywhere air could enter the intake all the way to the o2s for a leak where outside air could be coming through.
 

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My name's not Kevin
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308 Posts
An o2 sensor measures the oxygen remaining in the exhaust gas after combustion. It then sends a signal to the pcm telling it to either lean or richen the mixture. This is done through voltage. an o2 sensor will not send a signal until it reaches operating temperature. During this time the pcm operates in an open loop fuel control. If you o2 sensor is bad your pcm should revert back to this "open loop" to set the a/f mixture.
 

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03 Tahoe
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Sounds like time for a new o2 sensor :)

A bad sensor, or one that is really flaky will go rich, lean, whatever....it just won't be good.

Cameron
 

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GMFS Senior OG Member
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Discussion Starter #10
kevindepot said:
An o2 sensor measures the oxygen remaining in the exhaust gas after combustion. It then sends a signal to the pcm telling it to either lean or richen the mixture. This is done through voltage. an o2 sensor will not send a signal until it reaches operating temperature. During this time the pcm operates in an open loop fuel control. If you o2 sensor is bad your pcm should revert back to this "open loop" to set the a/f mixture.
Yes my scanner does say it's in an "open loop" I'll have to replace the 02 sensor tomorrow. Thanks god I work at an auto parts store that's where I bought it a few months ago (warranting parts is a good thing) I might of damaged it while hogging out the cat.
 

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internet bigot®
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i didnt know you gutted your cats... if thats the case, then you need to buy a dummy sensor, that has an already programmed optimal reading for it... otherwise if you put in another stock sensor, it will keep reading your exhaust as being rich, since the cat is no longer there....... therefore your motor will be running lean, and that could be why you are getting a stumble... not enough fuel is going to the motor.
 

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GMFS Senior OG Member
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Discussion Starter #12
Actually on my truck has only (one) 02 sensor not like most have 2 or 4 sensors, and my sensor is before the cat. Trucks with 2 & 4 have them before and after the cats. I think if the sensor was after the cat and yes I would need one?
 

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03 Tahoe
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That's the nice thing about most TBI trucks....no post cat sensors :)

Cameron
 

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GMFS Senior OG Member
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Discussion Starter #16
My 02 sensor is fine.. The truck is running alot better now.. :evillol:
Next is install the TB spacer.. I want to hear from you guys what's next on the list of mods?
 
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