I just got another 79 rx7, engine is fully stock and runs great. Got it for $850 including an extra 12a motor. In order to register the car in my name its has to pass smog. I have had it tested 3 times and each time the hydrocarbons at idle are too high, when revved to 2K they are well below Maximum, all emissions equipment are still on engine and looks exactly like my other 79, which passes smog with ease. I have put new spark plugs in, all are getting spark, both L and T timing are on mark. Am I running too rich? Also my crankcase is not evaporating properly( release of pressure heard when oil dipstick is pulled out) and previous owner increased OMP output(could this be the problem) Can't figure it out.

 

is your cat fully heated up before testing? it's best to go for a 5-10 minute drive on the highway right before testing and keep it as hot as possible until you actually test.

 

The car has the thermal reacter and heat exchange system, no cat, and everytime I fully warmed the car up.

 

Trying swapping out the cats between the car that passes to the car that fails. Definitely worth investigating the evap system.

 

In the FC, which cats can you omit? And does it shorten the life of the remaining cats if you do omit some?

 

Cali emissions tests are strict, throw in a known good stock cat in there for the test, put a couple gallons of E85 ethanol in the tank, and keep the engine running before doing the smog test.

 

i heard some guys just put 3 skyline cats in a row in a separate exhaust system that they install just for emissions testing, and then switch it back and do whatever they want for the rest of the year