My 95 Del Sol Si Vtech failed AZ emissions today. My NOx level was 4.14 and needed to be below 2.00. I also failed the gas cap test, but that is an easy fix. I've made a few changes to the car over the last year. It has not been tested since. Any advise on the NOx is appreciated. My only guess is the Cat. The changes are:

K&N RX-4870 Universal X-Stream Clamp-on
JDM Ram Intake
Flowtech 80524FLT AirMass Pro-Racing Header
Magnaflow 22628 Direct Fit Catalytic Converter (Non CARB compliant)
I also have a custom Magnaflow exhaust going up to the Cat. Not sure of the model without getting under the car.

The car was also running for 20-25 minutes before the test.

JHMEHxxxxxxxxxx Tag NP
Make HONDA Model Year 1995
Vehicle Style SEDAN Num Cylinders 04
Fuel Code GAS Standard Class GVW 6000 LBS OR LESS
BiFuel NO Odometer 153
Inspection Information

Test Date 01/25/2013 Test Time 08:07
Station M16 Lane 2
Test Type IM147 Test Seq 01
Inspector 1 5720 Inspector 2 0000
Test Fee $27.75 Pressure Result PASS - PRESSURE TEST
RTC 2492 4923 34A8 A151 Cat Result UNTESTED
VIR ID: N/A Overall Result FAIL

Tamper Inspection Information
Air Pump UNTESTED
Gas Cap FAILED AUTO Cat Conv UNTESTED
PCV UNTESTED Evap PASS

IM147 Inspection Information
IM147 Result FAIL
HC
HC Result PASS
HC Grams/Mile 0.70 HC Std 0.80
CO
CO Result PASS
CO Grams/Mile 4.74 CO Std 12.00
NOx
NOx Result FAIL
NOx Grams/Mile 4.14 NOx Std 2.00

 

how's the airfilter? maybe you got too much air getting in?

 

Is there more emissions information on the sheet? Can post a picture of the sheet?

Does the engine run hot on the temp gauge?

Is the ignition timing set to spec?

Have you replaced the fuel filter?

 

Cylinder temps are high, creating NOx... means somewhat of a lean condition... Have you changed the fuel filter? check you fuel pressure...

 

Non carb cat was the issue. Older cars in AZ are tested like California. I replaced the fuel filter, oil, gas, and cat. Tested clean. Thx