QuestionI recently had my 1995 Avalon smoged and it passed, but just barely. HC (PPM) @ 15 MPH measured 83 ppm with 84 being max allowable. Same measure @ 25 mph was 21 ppm with 49 max allowable.
Smog tech suggested new injectors. Your thoughts greatly appreciated.
AnswerEmission readings vary depending a lot on the circumstances at the time of the reading and to some extent from one machine to another and even what fuel is used, yes it passed borderline but nevertheless it passed.
There is an old saying in the repair business "If it's not broke, don't fix it" I think replacing the injectors will be a waste of time and money. The injector duration is controlled by the on board computer which recieves input signals from various input devices on the engine, this is how the length of the time that the injectors stay open controls the air fuel mixture, the injectors are only doing what they are told to do by the computer so replacing them is kind of like firing all the employees in a company when the manager is the problem.
If you are still concerned about the "high" HC reading I suggest doing a thorough tune up, high HCs are normally caused by incomplete combustion, in other words, all the fuel introduced into the combustion chamber is not completely consumed and the part that is not is pushed out the tailpipe, HC is just that, hydrocarbons from the unburned fuel, the catalityc converter is supposed to remove whatever is left, or most of it.
I would recommend having a toyota dealer connect the scantool to the computer and do an active test on the system and check the fuel trim readings and they can tell you if there is a cause for concern.
