L failed # i on the emisions test which is the HC l put new spark plugs in and had the throddle body cleaned and oil changed the reading is supposed to be 57 i had 128 took it in after spark plugs and throddle cleaner for my second test l got the exact same reading the second time HELP yours truly Mary

HC is raw or un burnt fuel. CO is incomplete combustion meaning the air fuel is burnt but not burnt completely. check O2 sensors for operation, fuel pressure, gas in oil or how long has it been since an oil change. check engine timing, dirty injectors. when was the last time a tune-up was done plug/wire condition is the air filter clean. just some things to check

get your injectors cleaned. change the air filter .change your plugs. put a fuel cleaner in your fuel tank.

Clean the throttle body and change the oil before the test. Get the car really hot before you take it to be tested. If it hasn't been tuned in years do that as well. Plug wires that are at the end of there life can cause a weak spark without a misfire and that can raise the HC levels

hi.
first thing to do is change the air filter. even if it appears clean, the airflow can be blocked enough to affect the petrol air ratios in the engine which will give high HC readings.
changing the spark plugs can give a cleaner spark, and better ignition, with lower HCs. high HCs could also be caused by traces of oil getting through worn piston rings and valve stem seals and burning in the combustion chamber. there are many oil additives that can help stop this and reduce HC levels as well.
hope these suggestions help

A few suggestions that can help a fresh oil change.I have seen dirty oil peg out the gas analyzer 9999 HC. Replacing the PCV valve if the valve is stuck open all the time it is pulling oil into the intake side of the engine and into the combustion chamber. Hope this helps.

Has anyone tried adjusting the fuel air mixture?

Based on what I am reading this is a gas engine and I am also assuming it is fuel injected. (Or does it have throttle body fuel injection?)

I suspect a case of dirty fuel injectors at the moment. They will need to be removed and cleaned.

If you have throttle body fuel injection then you will need the fuel air mixture adjusted.

If you respond can you let us know the "engine size" that is installed please. It would help us to help you in troubleshooting.

Thanks for using Fixya. Kelly.

i would say change the O2 sensors and a new cat ,these readings are well over the top ,could have a exhaust blow on exhaust as well which will throw out the O2 readings

it is probably bunring oil which is causing this,,,if it is burning oil you can try this to help it,sometimes it works and other times it doesnt,,,,,get the car good and hot,remove the spark plugs and get top engine cleaner and dump it into the plug hole,let it sit overnight if you can,,,,disconnect the ignition module and put rags over the plug hole and crank the engine a few minutes with breaks inbetween to get all the left over cleaner out the engine,,,,then plug the ignition module in and put the plugs in,it may smoke really really bad,,,just keep running it,,you may have to put foot on gas to start it,,,,,let it burn all the **** out the cylinders and then change the oil and get new plugs and that should help the oil burning if it is a oil burner and hopefully help the emission readings,,

Did you change the air filter. The fuel filter will have no impact on emmision's but the air filter is a very common problem.If you usually drive it at low rev.'s then before you send it for emmisions test you will need to put it in a low gear and floor it for about a mile the reason is when it is being tested the engine is reved up to around 3500 rpm and any build up of unburned fuel or oil in the exhaust system will put up the emmisions reading.

Do an oil change with 20W50 oil (or one grade higher) to prevent blow by during the test.

You current oil has HC from blow by though the rings.

Do a fresh oil change will lower the HC.

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Change spark plugs,wires,cap and rotor if they are over 24,000 miles
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Make the smog check appointment for the EARLY MORNING. Colder air will help the fuel burn better.

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Clean or change the air filter and pcv valve.

Clean Mass Air Flow sensor with CRC Mass Air flow cleaner or electronic part cleaner.

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Do a quick wipe down on the wires and cap to take the moisture off.

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Check spark plug wire contacts for corrosion.

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Fill the tank to around 3/4.......just in case your fuel pump is weak.

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Ran the truck for 20+ minutes on highway before the test.

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Do not carry excessive cargo on the truck bed.


These are the little things I would do to get the HC and CO down.


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