failed tx emissions

[oneline180]

-1993 s13 ka24deall stock except for muffler

my sticker expired march o3 i didnt go to try and pass emissions then because my car was accelerating poorly due to the maf. i had a blitz Stainless filter on it but i noticed that the stock airbox helped it run smoother.

when the old maf went dead and the enginge wouldnt start was the only time the check engine light came on. i got the new maf, then i reset the ecu after i messed with the distributor.

then i got another maf from a friend and it ran fine...for about an hour, and then ran like crap again. started messing with ignition timing (distributor-turned clockwise) reset ecu and it helped a little. went to try and pass emissions and it failed:

high spd HC limit: 132 - read-> 119 P CO limit: 0.73 - read-> 1.26 F NOx limit: 945 - read-> 2051 F low spdHC limit: 136 - read-> 152 F CO limit: 0.76 - read-> 1.91 F NOx limit: 1045 - read-> 2258 F

so i changed the O2 sensor bc it was consuming a lot of gas(barely 200 mi to tank, usually get aroung 380mi), it bogged at 2500 and higher rpms, somtimes at idle during warm up. reset ecu. the sensor did help when i tested emissions again BUT it failed the nox again:

high spd HC limit: 132 - read-> 46 P CO limit: 0.73 - read-> .20 P NOx limit: 945 - read-> 1606 F low spdHC limit: 136 - read-> 90 P CO limit: 0.76 - read-> .30 PNOx limit: 1045 - read-> 2644F

yesterday i messed with distributor and the screw at the back of the intake manifold near firewall (iav screw??) resest ecu. and it feels like it used to when i got the car a year ago, revvs smooth w/o hesitation.

the guy who ran the car the second time for the test said it was either the EGR sys or the Cat Convt. i havent checked for codes because this whole time the check engine light never came on.

help pls

[NISTECH]

EGR problem or lack of exhaust back pressure that makes it work. I just posted on an emissions failure for some one else find that thread and there is some basic tests you can do to the EGR system in it.

BTW welcome to NICO:)

[NISTECH]

http://www.nissaninfiniticlub....72750

[Nismo_Freak]

On a chemical level you need to reduce the heat of combustion, the amount of Nitrogen present in the fuel, and the use of a flue gas (aka the EGR's purpose). This translates into the following:

- Verify timing with timing light and at proper idle- Run 93 octane fuel from a good/high volume gas station- Verify EGR function

Water injection would let you pass as well.

If you reduce the amount of nitrogen present in the gas tank by as much as 18% (unlikely) then you can drop as much as 50% of your NOx emissions.

[NISTECH]

of the air that enters the engine78% is nitrogen,20% is oxygen and 2 percent is garbage in the air we breath. reducing the temp in the chamber will reduce NOx as the 2 primary things that cause NOx are heat and pressure the EGR is designed to cool the combustion chamber by allowing a vaccum leak essentially but without one important molucle needed to make the fire hotter,..oxygen. This is what the EGRs main function is.

[oneline180]

thanks u guys, sorry i took so long to respond, btw i passed, barely, used 93 octane, messed w/ ign again, valve, and i passed. still need to get a new maf or atleast another used one, depends on what my engine plans are, i ll prolly make a choice within a month.

thankyou for the welcome, and to Nismo Freak, wasap dude, i will see you soon and maybe challenge you to a battle on lime creek road, lol, wight u guys check ya laters, i need my sleep.