Ok, 1990 300zx just bought. The car runs insanely rich. The previous owner removed Cat. converter and said he removed the O2 sensor. Will this cause the car to run this insanely rich? Im very new to nissan, Im a supra guy, so forgive me if this is a stupid question.

The previous owner is a moron... Without the ECU knowing how much Exhaust Gas is flowing through, it gets confused, and makes the Engine run Rich.

Is there any Check Engine Light being thrown?

What you need to do is find some stock Catalytic Converters... OR, go to an exhaust shop, have them weld in two Oxygen Sensor Bungs, and put the Sensors back in.

That should fix the problem... Let us know if it doesn't.

-Wes

bungs will not be needed unless he replaced the headers. on the N/A the Oxygen sensor are located on the headers. did he even plug the hole that was left after he removed the oxygen sensors???

i cant even imagine the car running at all without oxygen sensors. if it is a 2+2, i have the midpipes with the stock cats in them for sale because i do not need them anymore. i also have the stock headers if the previous owner did anything stupid to those too. let me know...

reguardless, your gonna need to jack up the car and find out exactly what he has done to butcher the car.

yes, the engine light is on! I need to know where to install the bung... yes, he WAS a moron...

Well look on your Exhaust Manifolds (Headers)... There should be, like Jason said, Oxygen Sensor Bungs already in place.

If for some odd reason, they're not there... Take it to MIDAS, or an exhaust shop, and they'll know where to do it.

Good luck,

-Wes

ok, there is a sensor on each exhaust manifold... thats two. is thats all thats on this car?

Woah, wait... Are the Sensors in the bungs? Or are they out for some strange reason?

-Wes

in the bungs

Check the ECU for codes being thrown. Take it to Nissan and have them hook up the Diagnostics computer, or take it to Advanced Auto Parts, or Autozone, Pep Boys, etc and ask if they can check the ECU for codes.

And look it up from there... That should tell you what's going on.

-Wes

thanks, im going tomarrow

are the midpipes totally removed?

the stock cat. convertors are built right into the whole pipe section. their either had to be a gaping hole in the exhaust where he cut them out or he had a piece of pipe made to fit where the cats were.

do you have a digi camera?

I know there are Test Pipes (Straight through pipes, to replace the Catalytic Converters... Quite ricey for the road, quite racey to the track) for the Zed32.

Take some pictures, and we'll be able to help you better.

-Wes