Need help with lowering my NOX, i failed for the second time.

my setup, 1990 dx with d15b swap, running obd1 (p08 ecu)

ran seafoam, tried octane booster and alcohol from home depot. dont know if the NEW 2 1/4 exhaust with new magnaflow cat has anything to do with it. using megan headers too.

before running seafoam, octane booster and alcohol


hc 0.39
co 7.79
nox 2.71

results after using seafoam and running with octane booster and alcohol

hc 0.32
co 2.69
nox 2.92

Applicable standard
hc 1.00
co 12.00
nox 2.50

Please HELP!

 

u dont want nox it is from ur engine running too hot so higher octanes would only worsen this, all i could think of is find some thing to find ur engine to run colder

 

try retarding the timing.. say 5 degrees . i have a crx hf. i bumpt the timging a bit above normal. failed smog. i had done all the things you described plus new plugs, wires, distrib cap and roter, fuel and air filter, changed oil and filter, sea foam in fuel, sea foam sucked in thru vacuum. i was working on getting mpg up. took it to inspection, failed NOX. was suprised. went home, set timing at specs, went back and passed, results were the best in 4 of 5 years minimum (i keep the old inspection slips)s

 

lower octane would help as well. what did you put in before?

 

87 octane on the 1st try....

 

bump

 

make ur car run as lean as it can.

 

PASSED, retarded time, replaced 02 sensor, cheap at autozone for 20 bucks.