Went for my smog test today for my rx7 and it failed. On the first run the emissions test passed barely, but I failed my timing test. I guess I was a couple degrees advanced, barely infront of the 20 degree mark on the pulley. After he said the emissions passed but timing failed, I was like okay let me retime it and lets retest it. I put the timing to about 17 degrees advanced, 3 degrees retarded from stock because the tech recommended it and my numbers drastically changed in the Hc area for the better, but my CO got much worse. What does this mean, all I did was mess with the timing? What can I do to fix my CO #'s.

First run: 15mph, Hc meas 126 max 127, CO meas .11 max .79, NO meas 0078 max 825
25mph, Hc meas 87 max 101, CO meas .26 max .68, NO meas 0042 max 764, Final result: Pass
Second run: 15mph, Hc meas 55 max 127, CO meas .67 max .79, NO meas 0038 max 825
25mph, Hc meas 53 max 101, CO meas .77 max .68, NO meas 0070 max 764, Final result: Fail

HC went down after timing adjustment, but CO skyrocketted. With the new numbers, what can i do to get CO to go down and why do you think it went so far up with just 5 degrees in timing change.

 

do you have a working cat, a working airpump, and a working ACV? These cars pass emissions from the factory, with factory ignition timing.

 

The HC got better with the 25mph. This MEANS the ACV is not functioning at the low speed in my very humble opinion.

HC got better at 25mph BECAUSE the 02 sensor is now in the LOOP and working and covering up the lack of air from the ACV TO the EXHAUST PORTS. I did not say lack of air to the split air pipe, I SAID LACK OF AIR FROM THE ACV TO THE EXHAUST PORTS which are located prior to the 02 sensor.

The 02 sensor when in the LOOP leans out the mixture to the catalytic converter, much like what the air from the ACV does when its working right.

All this MEANS the timing should be set to NORMAL...........the TPS should be adjusted to output one (1) volt dc with a hot engine at an idle of 750rpm to 800 rpm (TPS is related to the ACV in that the TPS is the decider as to when the Relief and Switching solenoids work and in turn those two solenoids control the ACV's output.

I've no idea whether this car is turbo or non turbo so I ain't a gonna explain how to determine if the ACV is doing its job or not. Gone for the day.

 

i agree with hailers. and i'd like to add the timing probably was stock and they made it wrong, the 20 degree mark is the TRAILING side, with the timing light you adjust the leading, and if the trailing is not correct, its likely to be the TPS