Running a tad rich ? OEM NA6

[Basho]

I just changed my plugs and noticed that they were slightly sooty so as I blow no smoke , use nil oil (or coolant) but have a slighly variable fuekl consumption I deduce thatI an running a tad rich.

Why would this be so ?

Any tips gratefully received

[koop21]

i'm not sure why all of a sudden your car is running more rich then normal; but something you should know is na6 normally run rich to begin with because it uses batch injection.

[PaulF]

Do you get a bit of black sooty stuff on the rear bumper above your muffler tip?

[KevGoat]

My 1990 NA6 gets a reasonable amount of black "soot" on the chrome exhaust extension (though not on my bumper) yet mine also doesn't blow smoke or use any more oil than I'd expect. I thought I had a problem at first, but have since been thinking it must be normal as doesn't appear to affect anything.

[hks_kansei]

It's normal, they all do it.

[93_Clubman]

Yeah, it's common - my old NA6 was the same.

Standard 1991 NA6 fitted with wideband O2 sensor - results here:
viewtopic.php?f=29&t=39059&p=506711

[Basho]

Thanks for the replies all , nothing on the bumper and normal as clean as an exhaust pipe is , just got an overun of paranoia

[ja9]

Thanks for the replies all , nothing on the bumper and normal as clean as an exhaust pipe is , just got an overun of paranoia

Maybe paranoia but check the O2 sensor just to be sure everything is ok.

[Basho]

Thanks for the replies all , nothing on the bumper and normal as clean as an exhaust pipe is , just got an overun of paranoia

Maybe paranoia but check the O2 sensor just to be sure everything is ok.

Thanks renewed 5000ks ago with a Denso replacement but will check anyway