I just removed both exhaust manifolds and need some advice on whether I need to be replacing or checking anything while I have them off. Should I put new manifold gaskets on or use the old ones? I am also gutting the pre cats, so should I use new Mazda O2 sensors or universials? Correct me if I'm wrong, but I should only need the 2 upstream sensors, and need the part #'s! I odered a Dual O2 Simulator from Baker Electronics and 2 resistors to eliminate the 2 downstream O2 sensors. Does anybody have any experience and advice on doing this?

 

Have never been a fan of aftermarket O2 sensors. Here are OE numbers. Left upstream is a
KJ01-18-861A-9U. Right upstream is KJ02-18-861C-9U. Would definitely replace the manifold gaskets as you would not want to go back in later for a leaky gasket and they are only $6.35 each from dealer. Part #KL68-13-460 both side gaskets are the same so just get 2. Have never installed a simulator but one of the other guys here has and said it was very easy to do. Direction included were very complete.

 

Thanks for all your help! Here are some more part numbers for those Millenia owners who might need them! Down-pipe gaskets KL1940450, and the single pipe to converter gasket KL1440305! Also if anybody needs a newair box to throttle body gasket (air intake resonator grommet) its KJ0113245!

 

Left bank downstream O2 sensor. (closest to the radiator ).

Green is the sensor signal wire to the PCM.
Black w/ Yellow stripe is sensor ground.
Red w/ Black stripe is 12 volts in for sensor heater from the main
relay.
Black w/ Blue stripe is sensor heater ground thru the PCM.

Right bank downstream O2 sensor.

White is the sensor signal wire to the PCM.
Black w/ Yellow stripe is sensor ground.
Red w/ Black stripe is 12 volts in for sensor heater from the main
relay.
Black w/ Red stripe is sensor heater ground thru the PCM.

 

I got the car back together and it runs great! It feelslikea whole different car! I dont know how these cars even run with the precats being so restricted! I would guess it feels like 10 to 20 HP difference. I still got the TCS to figure out, but I will keep you all posted! Peace out my people!