When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I failed the Illinois emissions tests with high HC (2.11 instead of 1.6) and high CO (41.9 instead of 40.0).
Here's what has been replaced...
cat convertor (4 months old)
o2 sensor
tps
egr
evp
evr
ECTS
ACTS
plugs/wires/cap/rotor
I'm not getting any codes. No vacuum leaks that I can detect...and I've really checked.
Here's my question, I changed the Air charge sensor on the weekend and unhooked the battery to reset the computer. I hooked it all back up and drove it a few miles, then parked it until this morning when I drove it 15 minutes to the emissions test place.
Could my computer still be learning how to run? Should I have driven more than 15 minutes (city driving) to warm it up?
I was thinking of running some ethanol (1 gallon?) in the tank and getting it hot are retest it again?? any thoughts?
Try replacing your fuel filter. Our diesel had a 18 MPG new, and had slowly went down, we replaced the fuel filter, and ran some injector cleaner through it, and it went back up to 18. I would run a can of seafoam through it, and then replace the fuel filter.
Also, you should change the oil not too long before the test. This will help the HC readings since the old oil gets contaminated by fuel, etc. Then the vapors from all that get recirculated through the engine by way of the PCV system, resulting in higher HC readings.
can always clean the PCV valve, or replace it.
Keroseene works fine with the PCV and just blow it out with the air compressor.
can always try running better fuel in it too. Differnt gas stations have differnt additives.
That might make a difference.
Can always just run a take of 92 also, that will help clean injectors and such.
You don't want the higher octane gas in there when you get it tested. It burns slower if your engine isn't designed with the higher compression to need it's anti-knock properties. This results in higher HC emissions due to unburned hydrocarbons. It will also cause carbon deposits in the cylinders.
15 minutes is way too short. You may need several hours driving for the computer to fully "learn" your engine and you should always go for an emissions test after a highway run with the engine nice and hot, but not loaded up from city driving or extended idling.
I agree with the oil change tip. Also, don't fill the gas tanks. Full tanks can overload the evap system and increase HC readings.