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  1. #1

    Default Smog AIR Pump Requirement 1989 K 1500

    I have a 1989 K-1500 5.7L. I pressure washed the engine and the smog pump froze up. I took it apart and freed it up and it is running very smooth (it's a very simple vane pump).

    Knowing that a properly operating AIR system is only activated in OPEN loop during warm up or at full throttle, I am wondering if it is really needed. My state requires emission testing, but state testing is done in CLOSED loop mode and the smog pump should not be pushing O2 into the exhaust unless the tester floors the throttle (and I do not believe a floored throttle is tested).

    I want to remove the pump. Newer K-1500 trucks do not have a smog pump and I wonder why my K-1500 has one. There is a shorter ribbed belt that is used on these newer K-1500 trucks that will fit my truck and bypass the AIR pump.

    Any thoughts or suggestions??? Has anyone passed/failed a state emissions with the AIR system removed?

    PS: The AIR system on my K-1500 uses the pump, a very expensive diverter valve 2 one way valves. I am concerned about the diverter and the pump, has anyone replaced these with an electric SMOG pump made by Bosch for GM vehicles?

    The electric pump seems like the best, and most cost effective, solution. Using an additional relay the electric AIR pump could be made to operate only when the ECU wants it to run (exactly like the stock system).

    I look forward to a good comment thread. Thanks to all.

    If I do the exchange I will post a video.

  2. #2


    The smog(air) pump introduces oxygen into the exhuast to help burn hydrocarbons the EGR lets exhuast into intake under heavy load to help with detonation and NOX what you might have is a california emmission truck look for a sticker that says fed or california emmissions on core support.I have taken the vanes out of those pumps and had no trouble with az. emmissions there one step below cali.

    99 tahoe 2 dr. 4x4 7.4 4L80-e NP246, SAS, dana 60 hp, sterling 10.5 rear, gibson headers, and alot of tricks of the trade !!!!!!IF YOU'RE NOT CHEATING YOUR NOT TRYING!!!!!!!!

  3. #3



    I have a Colorado Truck. Luby Chevrolet... Colorado Emissions

  4. #4


    You live in have to pass colo. emmissions. The truck on the other hand has to abide by FED or Cali. standards And for it to have a air pump on a half ton tells me it was setup to pass cali. emmissions if it ended up going to a dealer there or it might have been transfered from there

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