This Page Contains information about How To Prepare Cars For Emissions Smog Test Things To Check Get Ready Pass By edwino85 in category Blogs with 12 Replies. Last Upated: Thu Nov 27, 2014 
this year i also had to get my car ready to the bi yearly required emission smog test set by the state and the department of motor vehicles (DMV)
every year its panic mode because you never know if you car is going to pass. so to make sure, or atleast increase the chances of your car passing i am writing this little guide to maybe help you get your automobile ready to pass the required emisions test. here is a list of things to checkEASY ONES- least expensive:
1. change your oil
2. change your oil fileter
3. change your air filter
4. change your fuel filter, if you havent changed it for more than 5 years
5. Change PCV (positive crankcase valve), these have a little valve that you can test, if you shake the valve and you hear "clicks" then you know its good, but these little suckers are know to get stuck, so if you shake it and you don't hear any clicks, they you defenetly need to change it, but i recommend anyway to replace before you go to the testing stationMODERATE - More expensive
6. Check/Change spark plugs. I usually just change them.
7. Check/Replace spark plug wires
8. Replace distributor rotor, if you have distributerless car, then you don't have to worry about this step.
9. Visually Check for worn or torn vacuum linesDIFFICULT - more expensive:
10. Oil leaks around the engine, an oil leak means that you are losing oil pressure. The PVC valve is also responsible to recycling these fumes, and if you have a leak, then your emssions system may not be working right. This can be simple or a difficult thing to do depending on you make and model car, but generally, engines leak around the valve covers, and all you need to do is replace the broken gaskets with a new gasket. These gasket are usually made of rubber, and when rubber mixes with heat, the more time rubber is exposed to heat, the rubber gets brittle and it breaks.
the gaskets would cost you around $10 dollars each.
11. Check for Exhaust leaks, How do you know when you have an exhaust leak. Well, you will know by the sound, since there is a leak, the exahaust is not being muffled (silenced) by your muffler and your car will come noisy as you exelerate the engine.
12. Check Engine Light (Lamp) is On - if you have the check engine light on and you have an emissions related code, your chances of passing the test are very, very low, if not impossible. so you defenetly need to check as to why you have. You can take it to a shop to tell you what's wrong with it. or you can take it to your local auto parts store, they usually provide this service for free. or you can buy a code scanner and connect it to your car's computer. There are alot of sensor in you car's engine that make your engine run effiently and cleaner, but if one of these sensor malfunction, then the computer is not getting accurate reading and it will make your car not run very well as it should.
13. check vacuum leaks
14. throttle body cleaning
15. Fuel injection cleaning
16. Check for EGR valve is working correctly
17. Check the exhaust, if your tail pipes are dispersing white smoke, you may have a water coolant leak, this will be very expensive to fix. If the smoke is black, you may have in oil leak inside the engine due to a bad head gasket, this will also be expensive to fix, starting at around $300 dollard and up. If the exhaust smell like gasoline after the engine has reached normal temperature (its normal if it smells like gasonline when its cold because the catalytic coverter is not hot enought to burn the exhaust fumes) but if your car has reach its normal operating temparture and it still smells like gas, they you have have a problem with your emissions or even your catality converter, but usually catalitic converters do go bad, they last pretty long, like ten years i would say, or it could also mean that your car is running too lean (more gas, less oxigen), then you will need a tuneup to fix this, which brings me to the next check;
18. Tune-Up, a when a mechanic does a tuneup, he/she should check all the things i've have listed here. they have special equipment to heck all these things, so remember, they've invested money on tools to check for symtoms in your car, so i guess that's why its costs alot. for an average 4 cylinder car, it would cost like $150, the bigger your engine gets, the more expensive it gets, like v6 or v8s.
19. The last you can do to make you chances better, is to drive your car for atleast 30 minutes before taking it to the station, this is what i do:
go 15 minutes on the freeway/highway, then 15 minutes on the street, then go to the station, and while i am waiting at the station, let the car idle until its time for the station do the test, buy this time you car's engine and catalytic converter should be running at optimal for burning harmful gass to the environment.
20. if you don't pass, the tech might suggest to check your engine. on some states its illegal for them to tell you what's wrong, they'll just tell you whether you pass or not, and you have to take it to special shops for repairs. but some might suggest what could possibly has gotten wrong on you car, things like your egr valve, catalitic converter, etc..
I hope though you have pass, but if you have not, remember my tips, I've only NOT passed once, and it was because I had a bad o2 (oxigen) sensor, once i replaced it and went back to the station shop, i passed with flying colors!!