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Help Guy's Running Headers With an O2 Sensor

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jc71355, Jul 8, 2002.

  1. jc71355

    jc71355 1/2 ton status

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    Help Guy\'s Running Headers With an O2 Sensor

    Where Did you put your sensor? I am running mine in the drivers side header collector. It is a Bosch Premium for whatever that's worth. I keep getting code's 13 and 44. 13 says it's loosing signal and 44 says it's running lean. I put in a new fuel filter the other day and that helped for a few days but now they are back. Is there a problem with the place i have my sensor mounted. The motor runs strong. Another thing i had to cut the wire and splice it in because the wire would not reach down to the collector. I redid the splice when I put the new sensor in. Anybody know what could be wrong? Thanks in advance.

    James
     
  2. ftn96

    ftn96 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    You "more than likely" need to move the sensor up closer to exhaust port. Now that you have headers you dont have as much exhaust buildup or back pressure. So the further away from the source you have it the less the O2 will be able to read the exhaust.

    On the other hand, I would replace that O2 with a new one while using some sorta professional "type" splice and not just wrap the wires and tape them.

    You may also want to just undo the negative battery cable for a couple of hours and let the PROM memory drain from the computer and then reconnect it. This should make the computer re-initialize everything without any memory or what you previously had and react within the hard set parameters.
     
  3. MEM

    MEM Registered Member

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    I'm about to do the samething you've done. I just bought the bung from jegs and can't wait to weld it in. The guy I bought the truck from put the headers in and didn't take care of the O2 sensor. My truck is running constantly on open loop mode. I'm getting about 9mpg.
    Getting back to your question, what kind of O2 sensor did you put in, the original one wire or a three wire setup? The three wire set up is a self heating O2 sensor. It assures that the O2 senor reaches operating temperature (600F I think). You may be having a problem with the O2 senor not reaching that high of a temp.
     
  4. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    The wires are crimped together in a fitting or whatever you call it. One goes in one side and one goes in the other and you crimp each side. I can't really move it forward much more than it is now, maybe a couple of inches but i don't see where that would make any difference? My fathers 95 Z71 has the O2 sensor way back where the Y-Pipes converge by the transmission, And if i'm not mistaken these are the same motors. Thanks for the help.

    James
     
  5. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    The sensor is Bosch which i consider a good brand. But i could be wrong. I'm doing about the same as you on gas milage /forums/images/icons/mad.gif . Of course I do tend to have a heavy foot /forums/images/icons/wink.gif so I always thought it was that. I put in the orginal style with the one wire. I'm not sure about the other one's. My headers are Jet-Hot coated so the are supposed to retain heat better but i dunno.

    James
     
  6. Diesel Dan

    Diesel Dan 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Your location shouldn't set the code 13. If it isn't heating up enough it just won't go into closed loop. Since the fuel filter cured it for a couple of days I'd check fuel pressure, maybe your pump is getting weak. Also that close to the collector make double sure the collector gaskets aren't leaking, that will set the code44 for sure and possibly the 13.
    BTW, I have edlebrock tubular headers on my '91 with the O2 sensor near the collector also.
     
  7. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Did not think about having a leak. I will have to get out there with some hose and check that out. I'm glad to hear that the position is ok. I didn't want to have to drill in my coated headers. I'm praying that it's not the fuel pump. I suppose I need to order a fuel pressure guage and see what it says. Thanks for the help everyone.

    James
     
  8. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    When installing an O2 sensor in the exhaust it needs to be as close to the exhaust port as possible if using the one wire O2, if you are running a full length header then you need to run a heated O2 sensor which is a 3 or 4 wire sensor. I would check fuel pressure though, my blazer was giving the same codes last week and a new fuel pump cured it.
     
  9. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    I was under the impression that if it wasn't heated it would go into the closed loop, like Diesel Dan said. If I do need one of these 3 wire sensors how would I kook it up?

    James
     
  10. BurbinOR

    BurbinOR 3/4 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    You do not necessarily need a 3 wire O2 sensor, especially now in summer. My truck (TPI motor) has Hedman Hedders with the O2 sensor after the collector and has no problems going into closed loop, summer or winter. I would still advise getting the 3 wire O2 sensor as it simply allows the motor to go into closed loop sooner which is a good thing. Easy hookup - one wire is a 12V 'key on' power source (lots of guys use the fuel pump power wire to hook into), one is a ground (easy enough) and the third is the sensor hookup you are using now.

    Definitely check that collector leak - that could cause a lean condition. /forums/images/icons/cool.gif
     
  11. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Any body know what part# this 3 wire sensor is. If it goes into closed loop faster this should make it get better gas milage right?

    James
     
  12. BurbinOR

    BurbinOR 3/4 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    This direct off the www.thirdgen.org board......... P/N AFS74 (AC Delco) or 25312179 - this is actually a sensor from a 4.3L V-6 but should work according to the guys on that board. Also heard the later model Vette 3 wire sensors work too..........good luck, let us know how it turns out.
     
  13. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Thanks for the help. I'm gonna check and make sure I don't have an exhaust leak right there and maybe check fuel pressure if i can figure out an easy way to put a guage on there. Any ideas on how to put one on? I know it has to go outside the cab. I was kinda thinking of getting a T-Block and putting it right after the fuel filter. This seems like the easiest spot to put one in since the braided line there will give. Any other idea's are welcome /forums/images/icons/smile.gif .
     
  14. K05Aggie

    K05Aggie 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Concerning O2 sensors, I have uncoated headers and my one wire sensor worked fine. It is about 8" behind the collector. I installed a three wire sensor anyway, just to make myself feel more confident. It is a Bosch sensor. The model number is either 19101BO or 982 I'm not sure which; there were lots of numbers on it. I just went to the parts store and asked for a three wire sensor. I can't remember which was power, ground, and signal. Just use your ohmmeter to figure it out.
     
  15. jc71355

    jc71355 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    Ok I found the problem. The collector bolts were loose thus creating a leak I'm thinking. When I listened to it through the tube I heard a chattering so I tightened everything up. The shop that put my exhaust on didn't use locking washers on the bolts so the were really loose. I am going with the 3-Wire O2 sensor soon. Thanks to everyone who helped /forums/images/icons/laugh.gif .

    James
     
  16. jcg

    jcg 1/2 ton status

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    Re: Help Guy\'s Running Headers With an O2 Sensor

    I've got full length ceramic coated headers and my single wire sensor works fine. I welded the bung in the exhaust tubing right after the collector flange and the wire reaches just fine. I think I opened up the wire harness a little to get the wire to reach farther down, but I don't remember. I'd say Bosch sensors are the best too, but that might just be because I used to work for them /forums/images/icons/wink.gif
     

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