Help with Passing Emmisions (Toyota Camry)

[BASS]

Ok, my dad's 1989 camry failed emmisions. We changed the spark plugs, distr. cap and rotor, pcv valve, and installed a new muffler (the old one had a small hole in it). The air filter was clean. We even put that "Gauranteed to Pass" additiive in the gas..

We took it back to the inspection station and nearly the same readings happened again (high HC and high CO, the NOx was ok though). Does anyone here have any clue what the problem may be? The car runs fine..

Maybe the oxygen sensor? EGR valve? Injectors clogged maybe? I dont think that the catalytic convertor would have anything to do with the high HC...

 

[unix_punk]

Im pretty sure the cat has alot to do with the high HC...but I'd say the O2 sensor has more to do with it... Do the O2 sensor first then the cat if you still fail... my .02... HTH

 

[Boost231]

Im pretty sure the cat has alot to do with the high HC...but I'd say the O2 sensor has more to do with it... Do the O2 sensor first then the cat if you still fail... my .02... HTH

wow crazy that it wont pass. i have a 94 toyota camry and it still passes like its brand new. i would change the cat out and also replace the 02 sensors. my o2 sesnors are getting lazy as well.

 

[BlackMetal]

I agree try the 02 sensors. Before giving up and buying a cat you could get one of those laser thermometers and do this test...

Checking converter operating efficiency can be done several ways. One "low tech" method is to make the fuel mixture momentarily rich by disconnecting the MAP sensor, or by creating excess HC in the exhaust by disconnecting and grounding a plug wire. Either condition should make the converter's operating temperature rise sharply, with the outlet temperature rising several hundred degrees over the inlet temperature. No change in temperature would tell you the catalyst is fouled and nothing is happening. Do not run this test for more than about two minutes because there's a risk of overheating and damaging what might be a good converter. Also, disconnecting the MAP sensor will likely set a trouble code, and on OBDII-equipped vehicles pulling a plug wire may set a misfire code.

Aim the thermometer at the exhaust pipe and check the temp before and after the cat and make sure there is a noticeable difference. If the exhaust isn't hotter after the cat you'll know it's not doing its job.