I own a 1991 honda civic 5 spd with d16a6 block with DPFI pm5 ecu

i dont have a print out of the reading because the smog guy did pre-test only before running through officially, but the NOX readings are still high.

Ok first time nox was like 2500 ppm

I also replace the CAT. Thought now for sure i will pass.

went back Pretest again NOX went down to 2000 ppm

Then i replace the IAT sensor because it was bad..CEL was blinking 10

Car ran sooo much better after the IAT sensor change, i thought for sure i would pass now.

Nox reading still at 1000 ppm

I then changed the O2 sensor, i have not gone back but im thinking about filling up with 92 octance throw some octane boost in tank run hot the test again tomorrow 2/25/11. Im hoping this works, but now im thinking that it wont....im frustrated what else can it be??
or what else can i do to help get the numbers down??

 

go for a drive on the free way and smash get the cat nice and hot

there designed to work better hot gl bruhh

 

or if that fails pm me if ur in socal

 

 

thanks...im gonna try one last time probably tomorrow or saturday, yea i will pm you in in glendale area in socal..tell you how it goes

 

well if u got the dough smog aint no problem

 

A high NOX reading is caused by high compustion temps or a lean condition so it is running lean.... i would say that replacing the oxygen sensor is i good start also might want to check your fuel pressure.....there are no vaccume leaks i hope....

 

check ur timing too

 

coming to u for my hatch lol

 

Ok went today,i changed a few vacuum lines, then sea foamed in vacuum lines tran hot with high octane...retarded distributor to get richer mix, timing is right on point, still not passing......still stumped, but no who worries I worked out a deal with the guy and I passed... : )