95 GSR failed emissions when i used my tuned ecu and again with a stock ecu. Mods are skunk2 IM, 2.5 header/exhaust, CAI. I replaced the Cat 2 weeks ago.

Tuned ECU:
15mph
Limit/ Reading
HC: 141/243 Fail
CO: .79 /4.21 Fail
NOx: 1088 / 628 Pass
25mph
HC: 136 /248 Fail
CO: .76/3.79 Fail
Nox: 984/887 Pass

Stock ECU:
15mph
Limit /Reading
HC: 141/193 Fail
CO: .79/.82 Fail
NOx: 1088 /2764 Fail
25mph
HC: 136 /36 Pass
CO: .76/ .47 Pass
Nox: 984 /956 Pass

Any ideas on which ecu I should use, and what I can do to bring down the failing numbers on it?

 

IPA will get you to pass with flying colors. Go to the store and buy some Isopropal (sp) Alcohol aka rubbing alcohol. Find the highest % and use a whole bottle to a half of tank of gas. Drive around a let it get worked in for 20 miles or so, then test. My integra with a straight pipe, no cat at all, passed this way.

 

High HC, even on a tuned ECU? Sounds like a bad partial throttle tune to me, as its obviously still running rich when it should be slightly lean.

Take the tuned ECU and lean out the partial throttle maps, get the car passed, then return it to your performance tune.

 

Any negative effects on the engine?

 

How old in the oxygen sensor?