Hy I have a 91 camry v-6 with 195,000 miles.I've owned since 40,000 and have never had a problem with emmisions before.I do all the maint. myself.All maint. is up to par except I have never adjusted the valves yet or did a compression test yet because the car runs like it always has and I'm getting the fuel mileage I have always got about 25mpg.The area I fail the emmissions test in is hydrocarons unburnt fuel in exhaust.The limit is .80 on my 1st test I had 1.46 after adding guaranteed to pass in along with premium fuel I lowered my HC to 1.42.Plugs have been installed 15,000 and all look like they are burning perfect.Pcv valve and air filter are new.Timing is right on at 10 degrees BTDC.The car runs a little rough at idle which is 600-700 but not very noticeable.It has all the power in the world when you step on it.The only thing that I know has changed since the last test when I passed is that I had a cat convertor installed about 6,000 miles ago and I'm thinking they gave me a cheap universal brand that is not as good as my original was.Does anyone have some thoughts on the matter as I am at my witts end with this problem.The only thing I did'nt try yet would be to retard the timeing a little and hope that gets it thru.I only have 2 more chances to pass the test.

 

I'm no emissions expert but you can look at High HC at this link:
http://www.autoshop101.com/forms/h56.pdf

The high HC and slightly rough idle mightindicate a leaking EGR valve. I would assume the simple things first that are the easiest to check.

 

Thanks for the site on emmissions Pedro.I put new plugs and a fuel filter on yesterday even thro the old plugs only had 15,000 on them.I'm really starting to think my cat. convertor is no good as that is the only thing that changed since the last test that I passed with flying colors.I'm going to stop by the shop that installed the cat and see if they will do anything about it.

 

You may also want to check the ignition wires to make sure there is no mis-fire caused by them. That web site link also has more good info as there are additional pages. Just change the h56.pdf to h55 and h57 to see more pages. The cat may be getting a too rich mixture. Maybe you can get an analyzer ahead of the cat to see if it is the cat without just re&re-ing parts.

 

Finally passed emmissions $300 dollars later.The last thing I did was put new wires,cap and rotor on.I still did'nt trust taking it in for a recheck and failing again so I took it to a shop that has a gas exhaust analizer.They checked and said they cleaned the system up enough to get it to pass which they did but still without great numbers.They also said I had a weak cat. convertor which was just installed 8,000 miles earlier at a chain store.So after I left their I went back to the muffler store and demanded a new convertor for the cost of labor which was $70.I'm glad this ordeal is finally over.This emmissions is just another scam against the working man as the car was running fine at the start of this fiasco.Thanks for your thoughts on the matter Pedro.Have a good one

 

The cost for clean air is the result of massive growth in population and industry. As frustrating as self diagnosis is for untrained vehicle owners I don't think you'd like the cost of dirty air either. Back in the 80's I was in LA and could not believe the smog. I was there for 3 days before I realized there were mountains to the east. Went up into Mulholland Dr. and saw what a blanket of smog looks like over a city. Get used to it if you want unlimited growth.