myrrh81

I was wondering if anyone had any suggestions besides the usual. I have a 95 Civic DX with an JDM OBD1 B16. HC CO was fine but NOX was 1522, when passing is 1372. I use the O2 sensor from the engine, converter from the DX, stock intake and exhaust. My timing may be off a bit. My old EVAP System had a port on the DX manifold which doesn't exist on the B16 so I never hooked up the EVAP. Could that cause high nox? Well, If anyone knows something about this I would appreciate some advice. Thanks

myrrh81

I forgot, my old engine blew a head gasket and there was a lot of water in the exhaust. I think this might have damaged the converter.

97civicdx

What ecu u using, hopefully not the jdm one

myrrh81

The P30. It came with the engine so I'm sure it's the original JDM ECU. Are the USDM ECU'S different?

95sloweg

usdm and jdm are diff ecu's

myrrh81

why the ecu cause only slightly high nox levels?

myrrh81

I guess no one has experience in this area. I know this is a difficult issue, Thank You anyway.

gourley

Just retard your timing (move the dizzy twords the front of the car) and goto inspection. Your car will run like **** for the time but it will lower your nox alot. Then get home and move the dizzy back to where it orgionally was. Use a timing light when moving the dizzy back for the correct timing.

jlsmi2

I have a 94 USDM GSR swap (b18c1) in my 92 hatch and just failed NJ emissions for high NOx.

I have the USDM p72 computer and have passed twice before.

I will adjust my timing, it was a little off, but i'm not sure if this will make that much of a difference. what are other solutions to lowering NOx? Please note that it passed in the other two categories, so ONLY NOx was high.

Thanks

Ex-Eg-Driver

iTrader: (1)

did u try using HEET?

thesmogman

Well I will tell you that coolant will contaminate your O2 Sensor and Cat.

Set your timing 1 or 2 degrees before spec to lower nox.

jlsmi2

What does HEET stand for?

How would COOLANT affect the o2 sensor/cat?


-- Plan to adjust timing, change the plugs, etc and oil but still not sure if it'll bring me down enough.


This may seem like a really simple question but how do the o2 sensor and catalytic converter affect the level of NOx? I thought they had more to do w/ the level of HC and CO...


Which is more likely o2 sensor or cat or just timing?