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Emmisions question.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Khi5in, Mar 29, 2003.

  1. Khi5in

    Khi5in Registered Member

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    I got a 86 305 4 banger. rochester. It has a knock sensor but no est module. No aldl connector. no 02 sensors. Basic 4 bblelectric choke vac. advance, egr, early evap sys. I've adjusted the air fuel mixture, and the choke.Timing ok, got better, but Still very lean burning. This thing burns your eyes. Runs very well but can't get rid of the smell, any ideas on the system i've got and a fix to this?
     
  2. Z3PR

    Z3PR Banned

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    Sure that smell isn't comming from the cat. ????
     
  3. Khi5in

    Khi5in Registered Member

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    I don't think so. Its a lean smell. you stand near the exhaust and you'll cry. wish I had a lab scope. I would think the cat would give you that rotten egg smell or something to that effect.
     
  4. the professor

    the professor 1/2 ton status

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    If its running smoothly, and particularly if you can get "response" from the idle mixture screws...I have to go with the previous post, and your just smelling the cats..
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    Ethanol, and "lo-sulphur" fuels, don't get a "rotten egg" smell..that the "sulphur" in the fuel
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    Just in case, some other things to check
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    Did you check the EGR for leakage..a small internal leak will make it run lean..
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    Did you check the obvious for vacc leaks..particularly under the carb...the factory "insulator gasket" needs occasional replacement..
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    Both these problems are unlikely if it runs smooth and you can get adjustment
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    On the other hand, if the AIR pump is not working, and / or if the AIR line check-valves are bad..you could be smelling a rich mixture burning your eyes..

    The cat could be either "not lighting" because of insufficient O2 in the exhaust..caused by a bad AIR pump, or the cat may be "coated" and not working for the same reason
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    I am a certified California EA smog inspector...(among other things) /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  5. Khi5in

    Khi5in Registered Member

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    Thanks, Egr is working and as far as i can tell there is no vaccum leaks. Most vaccum lines were replaced for dry rot. The base gaskt was replaced also. As far as the air pump system I will look into that. Although I've never seen a rich condition cause burning eyes, It could be, and who am i to question a california smog inspector. we all know the tough smog laws in cali.(lol). I am a certified auto technician but older carburated cars are not my specialty. Thanks for the help and any more suggestions would be welcome.
     

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