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!

 

had two friends with the same problem.

Case 1: LS into ej1. cai, headers, hi-flo cat, two resonators and aftermarket can.

Even after doing all that chemical stuph his hc was into the hundreths, and co just above 1.0, but still had too much nox.

Case 2: LS into VX. Stock box, stock exhaust manifold, AND stock can.

Passed the Ref.

Could be worth a try.

 

check timing, play with it

 

bump

 

This is a list of things to check i got from a member who worked for the DMV when i was having a similar problem...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">This is a suggested order for NOx failure of things to check:
1. EGR System
2. O2 Sensor
3. Timing/Spark Advance
4. Catalytic Converter
5. Incorrect/faulty thermostat
6. Coolant Temp Sensor may be open
7. MAP Sensor
8. MAF Sensor
9. Other sensors/switchs (uhhh yeah, ok)
10. Fuel Injection System
11. Faulty On-Board COmputer
12. Computer PROM
13. Internal Engine Repair

High HC Failure:
1. Spark Plugs and Wires
2. Timing Spark Advance
3. Vacuum Leaks
4. Other Ignition Problems
5. O2 Sensor
6 Evaporative fuel system
7. Fuel Injection System
8. Air/Fuel Mixture Adjustment
9. PCV System
10. Catalytic Converter(s)
11. Throttle Position Sensor
12. MAP Sensor
13. MAF Sensor
14. Other Sensors/Switchs (dohh, again)
15. Computer PROM
16. Internal Engine Repair

High CO Failure

In the case of carb engines, up to 85-86
1. Choke System
2. Carburetor Repair

In the case of fuel injected engines, from 1986 on,
1. Fuel Injection System
2. Induction system problems
3. O2 Sensor
4. TPS
5. MAP
6. MAF
7. Coolant Temp Sensor may be closed
8. OTher sensors/switches (I guess this is a CYA thing (cover your ***)
9. Valve train problems
10.Jumped engine timing belt
Plus...
Idle speed adjustment
Air Filter Condition
Thermostatic Air Cleaner
Air Injection/Reaction System
EVAP fuel system
Oil and Filter Change
Catalytic Converter
Computer PROM
</TD></TR></TABLE>