[-Premium gas, with "Guaranteed to pass" formula, then refill with premium
What the heck is that?
hope it is not one of those $7.99 a bottle formulas that is Guaranteed to make the seller rich that people find in Auto parts stores and actually believe it will do anything but take their money,and don't bother trying to get your money back as you have used up the "Guaranteed to pass" formula and most certainly they won't take back your empty bottle and failed report...I am no
expert but I have repaired 100's if not 1000's of failed
Vehicles since the 90's and do hold a current California Inspectors license...
When an engine is tuned to produce low CO and HC numbers, it typically produces high NOx numbers. That's because as the combustion chamber temperatures increase, the engine runs hotter, and the hotter an engine runs, the more NOx it produces.
What can you do? The combustion temperatures can be brought down by (1) retarding the timing (provided the tech doesn't care if the timing isn't on spec - not likely), (2) run richer (this will increase the HC level, but your numbers indicate you have room to maneuver), or (3) install/fix/do whatever is required to get a functioning EGR - which will lower combustion chamber temperatures.
I also have a issue with smog check, my #s are
15mph HC max 81 meas 197 CO max .47 meas .63 NO (PPM) max 685 meas 1168
25 mph HC max 47 meas 188 CO max .44 meas .44 NO (PPM) max 696 meas 1632
Have not done anything yet, thinking egr valve, what else? last tune up was less than 10K ago. 93 400E
just pay $150 to pass the smog. take out the cat. & use a straight pipe to a good amg. remus, brabus, lorinser, etc...man you will feel a big difference. feels like u have a header. if u want it quiter, use a pre-silencer, instead of a cat. then u can use a magnaflow freeflow, which is all s.s., looks nice & cheaper than the $1000 mufflers.