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Emissions test

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigjbear, Oct 6, 2000.

  1. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Has anyone tried or ever heard of putting denaturated alcohol in the gas tank to pass emissions? Any other quick fixes?
    Jim '80 GMC.

    It's a Wheelbase thing, You're Jeep wouldn't understand!
    http://www.bigjbear.coloradok5.com
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Make sure there are no vac leaks. A good tune up with a stock or a deg high timming (gives a hair more burn time if you got slop in the timming chain), good plugs and wires, lean out the idle scews, hose the cab down with cleaner and make sure the choke fully drops once warm and get it good and HOT before going and have super unleaded in it and a clean air cleaner. Might not be a bad idea to dial the choke back one notch to make sure it's not richening up even if the choke appears to be off. Make sure the EGR is working by while at idle hook it to a vac source that will activate it. It shoud idle bad if on at idle. Then try to verify it opens above 2000 RPM. They might try to roller test it but with your 35's they will probably due a static test.
    Never had one of the K5's fail doing this even when one didn't have cats when it was supose to and it still passed the sniffer. Stupid POS Ford failed most of the time and it had Fuel injection!

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Where I live they put the truck on a dyno and do a "loaded" test as well as an idle test. Your truck has to be pretty out of tune to fail on the drive test but the idle test was what my truck kept failing. I finally broke down and took it in to have the exhaust analyzed. The guy there charged me $20 to hook it up and just adjusted my idle speed up from 600 RPM to 1050 RPM. You would'nt believe how much cleaner it runs idling that high. There is a sign at our testing stations that says they will not test a vehicle that is idling above 1150 RPM, so we set it to just below that and turned the idle back down to 600 after it passed.
    [​IMG]

    They have now installed special adjustable dyno rollers for the 4x4's here. They have front and rear rollers that adjust for wheelbase, so they can drive test the fulltime and AWD vehicles.

    I thought it was amusing enough to watch my Jimmy with 35's trying to climb out of the rollers last year![​IMG] This year should be even more amusing. Funny part is every year the tester always seems to be some really young dainty litle thing that can barely get in my truck, never mind handle the clutch![​IMG]

    Well thats my trick anyways, the mechanic says the higher idle helps compensate for the extra little bit of duration on my cam, but the trick worked on my friends 79 Ford that had never once passed in its whole life!

    Rene

    [​IMG]
     
  4. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Thanks guys. I am going to clean the plugs, increase the timing and look for vacuum leaks. I failed on CO% it was 3.51, max was 2.49. It passed on everything else. The EPA sticker under the hood say my Q-Jet is not adjustable. I seem to remember something about the adjustment screws being just painted over. Does that sound right? I had it good and hot. The air filter, breather, and PCV valve are new. Fresh oil change, too. Grim, they put it on the rollers. One guy was a little nervous that it might jump out, but remember I live in Paulding County, they're used to 4x4s. Everyone commented on the noise the tires made.
    Jim '80 GMC.

    It's a Wheelbase thing, You're Jeep wouldn't understand!
    http://www.bigjbear.coloradok5.com
     
  5. Toad

    Toad 1/2 ton status

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    My 76 had everything new. Plugs, Wires, Air, Breather, PCV, etc. It failed. Then I remembered I hadn't changed the oil in over a year (I only drive it about 6,000 mile a year anyway and it leaked oil so bad it didn't matter).

    My neighbor who owns the shop looked over the carb and said it looked fine, everything seemed to be set right. He also said that along with the dirty oil, the truck being so old it probably has old oil and carbon built up inside different parts of the motor and intake. Instead of making me clean out the motor and intake, he turned both screws closed and opened one just a hair then adjusted the idle. It passed but I wonder what I'll run into in the future.??
     
  6. Toad

    Toad 1/2 ton status

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    My 76 had everything new. Plugs, Wires, Air, Breather, PCV, etc. It failed. Then I remembered I hadn't changed the oil in over a year (I only drive it about 6,000 mile a year anyway and it leaked oil so bad it didn't matter).

    My neighbor who owns the shop looked over the carb and said it looked fine, everything seemed to be set right. He also said that along with the dirty oil, the truck being so old it probably has old oil and carbon built up inside different parts of the motor and intake. Instead of making me clean out the motor and intake, he turned both screws closed and opened one just a hair then adjusted the idle. It passed but I wonder what I'll run into in the future.??
     
  7. White Knight

    White Knight 1/2 ton status

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    Have a 77 GMC P/U with 300,000 on it and it used to fail all the time, and thats with everything to specs and all the pollution stuff hooked up, but I started emptying the tank and putting in 5 gallons of 102 aviation fuel in it with a can of 108 booster also, it passed great and then around the corner to fill the tank up completely, have done this for 4 years and the truck has passed every year. Only reasoning I have is that stuff is so hot that theres nothing left to pollute with...bubba thinking mind you!!!!but it works!!!Now I don't put 1500 miles on the truck each year now...K5 took over my life and I'm addicted to it.

    White Knight
     
  8. 82Jimmy

    82Jimmy 1/2 ton status

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    my uncles k-10 failed and failed and failed some more, he finally put 2 gallons of super, some methonal, and a little booster. He passed with quite a bit of room to spare. Lots of people that run no cats i here weld them to make it look like it, then they get there headers to leak some so not too much of the stuff goes to the sensor....just my 2cents of small knowledge


    10 out of 11 people prefer Jimmys over Blazers.
     

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