Side effect on having Walbro fuel pump w/KA?

[94_240sx]

I have stock KA with Walbro fuel pump. After I installed it, I couldn't pass emission because of high Nox. I know high Nox is caused by bad EGR valve or catalytic converter. Is it just a coincidence or Walbro high pressure fuel pump can cause it? Just curious. BTW, I put RXP in my gas tank, and I passed it two times so far.

[MELLO*SOS]

I ran a walbro on my KA for a year or two with no issue. You might want to get an adj FPR so you can be sure your stock rail pressure is correct. Not sure on your smog question, that's not a concern here. GL!

[94_240sx]

I want adj FPR, but I heard it's not easy to install on KA. Anyway, I got a good OEM fuel pump now. I tested it and it was running quite and strong. My old one made a lot of noise and didn't sound good. I'll go to inspection this weekend and if I fail, I'll swap the fuel pump and go back. I can barely pass with a bottle of RXP in the gas tank.

[s13silvia123]

cahnge your motor oil and let the car run for 30 minutes is a plus to lower NOX

[94_240sx]

Found a used OEM cat and installed. Passed inpection yesterday with no problem. It was a catalytic converter. I'm relieved now.