My 2500 rpm smog test passed but not my idle test. Max is 100 for the HC (ppm)but my 97 GS-R put out 242. I installed plugs, wires, cap and rotor. It has a high flow cat, DC JDM 4-1 header and a Blox Im, with nothing else done to the head. The car was only running 20 minutes prior to the test so it was at normal temp. Idle was at 761 rpm and I set the fuel pressure at around 29 psi, any ideas to get my car to pass would be great, thank you.

 

 

How many miles are on the high flow cat.? When I perform a TSI(two speed idle test) I let the rpms down slowly to idle. I would try another smog station, if it fails again you'll need a new converter. Normally, aftermarket coverters will last about 2 years.

 

There are only 400-500 miles on the cat. Thanks for the response.