1994 80 Series. Owned since around 2008. 198k miles. New catalytic converter in 2008. Emissions not due until February but with new emissions standards starting 1/1/21 I decided to get an early test. Failed first test on Nox. at 5.78. Standard is 4. Passed HC at 1, standard is 2. That test run with ethanol fuel, timing at around 12 btdc, tires around 28 psi, overdrive off and ETC off. Second test failed again on Nox 5.25. Co .84. Second test run with straight gasoline, no ethanol, timing at 5 btdc, Tires at 40psi, overdrive off and ETC on. Couple of questions:
Any hints as to how to get Nox down.? It's been as low as 1.6 on previous years' test. I know it's caused by high combustion temperatures or pressures, above 2500 degrees and I believe the EGR system is designed to reduce those temperatures. I've had no check engine lights in the last few years and no known problems in the EGR system. Is there a method for forcing the EGR on to keep combustion temperatures down?
Anyone ever got an emissions pass exemption from Colorado for an 80 series? I think you have to spend around $700 on repairs to qualify. Is this a good option?
Is there a super duper catalytic converter which will reduce emissions more than the OE style?
Anyone know a good 80 series emission tech in the Denver area?
Anyone know exactly how the new 2021 CARB emissions standards will effect testing for 80 series? I did some googling but couldn't find any details. When we bought our 8, the NO standard was 9 and the CO standard was 4, so passing standards have been cut in half since 2008. If the standards are tightened any more it seems it may become impossible for an 80 to pass the Colorado emissions test.
General irritation: the tests seem wildly unpredictable. In 2016 it failed due to a bad gas cap. Nox on that test was 3.14 I drove 1 mile to a parts store, bought a new gas cap and returned for a second test, all within 15 minutes. Second test, Nox was 1.7. WTF?
Any hints as to how to get Nox down.? It's been as low as 1.6 on previous years' test. I know it's caused by high combustion temperatures or pressures, above 2500 degrees and I believe the EGR system is designed to reduce those temperatures. I've had no check engine lights in the last few years and no known problems in the EGR system. Is there a method for forcing the EGR on to keep combustion temperatures down?
Anyone ever got an emissions pass exemption from Colorado for an 80 series? I think you have to spend around $700 on repairs to qualify. Is this a good option?
Is there a super duper catalytic converter which will reduce emissions more than the OE style?
Anyone know a good 80 series emission tech in the Denver area?
Anyone know exactly how the new 2021 CARB emissions standards will effect testing for 80 series? I did some googling but couldn't find any details. When we bought our 8, the NO standard was 9 and the CO standard was 4, so passing standards have been cut in half since 2008. If the standards are tightened any more it seems it may become impossible for an 80 to pass the Colorado emissions test.
General irritation: the tests seem wildly unpredictable. In 2016 it failed due to a bad gas cap. Nox on that test was 3.14 I drove 1 mile to a parts store, bought a new gas cap and returned for a second test, all within 15 minutes. Second test, Nox was 1.7. WTF?
