Radio88

I am after some real tech people in here to help me out with a car that failed smog (CA.) twice-the Nitrous Oxide section.
It's an '87 Celica GTS with 77,000 miles on it-all original...first time in 29 years it ever failed smog. It passed the other stuff with flying colors but apparently failed 1st one at 15mph and the second one at 25mph.
It barely gets driven. My gal's little cruiser for errands around town. So it has fresh tune up parts, clean oil, we took it out prior to the second test today and ran it all freeways for an hour.
Maybe EGR? Just looking for opinions about the why's.

mmarshall

Could be the oxygen sensor. If you are not familiar with it, in cars of that vintage, it generally looks like a small spark-plug, with a wire on it, sticking up out of the exhaust manifold. Unfortunately, the very hot temperatures of the exhaust pipe sometimes burn the threads in so much that it is very difficult to unscrew, and special methods have to be used to extract it.

Radio88

Thanks for the reply. What confuses me is that this car does have its onboard computer monitoring parameters and never once threw a code or engine light! The O2 sensor, the converter, the EGR system, etc all are monitored. I need to find out if Ca. changed the game rules for this car or what. It runs very well too. First fail in its whole life. I guess it's down to contacting that "referee" guy.

rld14

It's an OBD1 car if that, it's (no offense) "stupid".

OBD2 cars have the ability to monitor their own emissions.

Radio88

Yeah but it would at least tell me if one of those components failed.
So do you have any advice regarding the failed smog thing?

Coleroad

Well I would do a real fuel injection cleaning. I would change the O2 sensors since they are cheap on that car. Also I would clean and or replace the maf sensor. Clean the throttle body. Clean the iac at the same time. That is where I would start.

Radio88

Good post thanks. I have less than a month to do this so I will start with stuff like this.