I removed my cats from my 1995 D90(offroad only). I also changed the tune resistor to the Euro 470 ohm(without cats), and adjusted the MAF to 1.2 volts. Should I try the Aussie 180 ohm(without cats) or adjust the MAF to something else. I searched but found nothing. The computer is a 14cux. Thanks Tim

Why did you adjust the MAF? The O2 sensor should still be present.

My 95 Disco runs just fine without cats and no tune resistor change (although I don't think NAS disco's ever got a tune resistor)

I'd put the MAF back to where it was and run the NAS tune.

CJ5-I still have the O2's and I changed the MAF idle voltage from 1.8 to 1.2, because when running no cats you are need to. I had the toxic smell before I changed the MAF voltage. The 14cux in the D90's have all 4 tunes. Tim

you should only have to mess with the maf voltage if you are running a tune resistor that eliminates o2 sensors along with the cats. Since there is no post cat o2 sensor the ECM is oblivious to any mods done back there. You mentioned a wideband in another thread. what pre cat AFR's were you seeing before you messed with the MAF?

How are you guys modifying the MAF bias voltage???

I put the cats back on my disco recently, because it was even more of a dog without them. not to mention that it was LOUD AS FAWK with the cats hollowed out and the flowmaster. better now.

Please note that the following air flow meter settings should be made when the engine is warm.

The air flow meter wires can be accessed by pulling the rubber boot carefully backwards along the cable. Under here you will find the following wires. Red with Black trace = Sensor ground, Blue with Green trace = air flow signal, Brown with Orange trace = Ignition live 12 volts and Blue with Red trace = CO trim value. A digital multi meter should be used and connected to the sensor ground and CO trim value wires. The values that you are trying to achieve are below and these are adjusted by the screw on the side of the airflow meter.

Air Mass meter setting (non cat). The voltage reading on the CO value here should be between 1.0 and 1.5. If you have the Tornado ECU chip fitted then 1.5 volts should be aimed for.

Air Mass meter setting (cat). The best setting for the CO value here is 1.8 volts.

This was taken from RPi's site. I emailed them and they said they allways change MAF voltage to 1.2 when running no cats, but still use O2's. The reason I changed voltage was to get ride of the "smell". I can't be the only one with no cats and still running an O2.

I have a truck with no cats flowmaster and a short dump. It's a d-90 the only thing my exhaust smells like is gasoline. I never changed anything in the maf and it runs fine.

-ben