My 89 cherokee keeps failing emmissions in TN. I'm barely failing. i'm .04 hydrocarbons over and 2.00 carbon monoxide. I need my jeep to pass by tomorrow so I can drive to work... any help?

 

89cherokeelimited,

i read your dilemma and i had gone through the same exact issue back in 2006 for my 88 cherokee. my mechanic found that my oxygen sensor was inoperative. he replaced the sensor and then it was fine. that might be your problem.

89cherokeelimited....

forgot to mention that the replacement o2 sensor should run you no more than $90. also, you might want to replace your gas cap - $15 at the most.

hopefully these 2 things can solve your problem. i'd try the least expensive first which is replacing the gas cap first.

 

The gas cap is pressure tested when the vehicle is inspected it TN so that would probably be an unneccesary replacement.

 

I just ran it through emissions one last time and the hyrdocarbons were 186 but the carbon monoxide reading was 3.02 and it can't be over 2.0 reading. I heard something about checking the vaccum lines... I've tried to see which ones would affect the carbon monoxide but every website says something diff

 

Both are a result of incomplete combustion,co is to much fuel and not enough air,hc is incomplete combustion,the hc number is very high and the co is close. What it is saying is you have unburnt fuel,But a new cat would remove that to levels that would pass,Is your cat old or new?
Did the smog station offer any recommendations?

 

make sure you get it good and hot before going to test. and "old school" trick is to get a little propane torch and glow the cat just before the test.
I'm not sure how far your drive is to the smog shop but if your exhaust isn't fully hot that will hurt you.

 

I'm about 6 miles from the station. But I drove it all day and hit the bypass doing 75 mph and that's when it passed the Hydrocarbons but the carbon monoxide still high. I'm gonna try the injector carb cleaner through the brake booster line. Oh and I changed the oil in Dec and It sat for about 6 or 7 months without even being turned on and now around 9 months and it still has the same oil in it so I need to change the oil but i'll do that in a day or two

 

Fill up with premium gas, it's supposed to burn cleaner