1990 f250 ??????
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Joined: Dec 2004
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1990 f250 ??????
I failed oregon smog check and it says the high rpms were creating to much emmisions-everything else was fine--no codes--its a 460 efi--if it is a sensor can you also tell me how to check them?Also tried the guaranteed to pass stuff but it didnt work.Truck runs great --anyone know any quick tips on how to pass?Thanks
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Joined: Sep 2004
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Check your ignition timing. Make sure it is set to stock specs. Overly advanced timing may cause fast idle and failed emission tests.
Run a KOER test. If the idle is indeed too fast, the computer should set codes which will be helpful to diagnose this issue. It will also check for proper mixture ratio as reported by the oxygen sensor. If the truck can't control mixture ratio during KOER, it will probably fail emissions. This test is also the preliminary step in setting the idle speed in at least some of these trucks.
What were your CO, HC, CO2, and NOx readings from the failed test?
The catalytic converter may have worn out/failed/been tampered with over the years.
Run a KOER test. If the idle is indeed too fast, the computer should set codes which will be helpful to diagnose this issue. It will also check for proper mixture ratio as reported by the oxygen sensor. If the truck can't control mixture ratio during KOER, it will probably fail emissions. This test is also the preliminary step in setting the idle speed in at least some of these trucks.
What were your CO, HC, CO2, and NOx readings from the failed test?
The catalytic converter may have worn out/failed/been tampered with over the years.
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