DANEGEROUSD

I Put A Header On My Yoda And It Came With A Midpipe, So I Decided To Delete My Cat. By Doing This My Rear O2 Sensor I Causing A Check Engine Light. I Was Wondering If Anyone Knew Of Anybody That Made A Diode Or Plug To Delete It, Or If Not The Ohms Frequency That It Runs On So I Can Delete It Myself.

Elvota

Pretty sure the O2 sensor has to be active, and can't really be fooled. I don't think it is a constant reading. If it tells the engine something that isn't so, you may start having issues the computer will make worse.

phorensic

On my 3vze I have two O2 sensors, one before the cat and one after. I gutted my cat and never threw any CEL's. My Master ASE technician friend says that if I were to unplug either O2 sensor that it would throw a code. Therefore, I suggest you replace the O2 sensor that is not working, and it will probably fix your problem.

I'm a little confused by when you say ohms frequency it runs on. If you want to plug something in to the harness that is usually plugged into the O2 sensor to "fake" the ECU into thinking that there is a working O2 sensor, then you might be able to do that. I've seen boxes labeled something like "O2 faking circuit" or something like that for sale. It might be as simple as a 10KOhm resistor, or it might be a signal generator (sine, square, or sawtooth).

regularguy412

Need to weld a bung in after the 'Y' and get your O2 sensor back on line. ECM won't like not having that info.

Mike in AR

trythis

Some people might be offended by your not using the catylitic, converter, adding more greenhouse gasses Dumping poisonous gasses out. Your also losing necessary back pressure and making your engine less powerful. It really does work better with the cat installed.

phorensic

Backpressure is a myth. Ideal exhaust on a naturally aspirated engine is a zero backpressure system with the right flow velocity for the desired powerband.

An exhaust sytem on a 3.0L V6 with 2.25" piping with no catalytic converter and minimal mandrel bends will flow better than the same system with a catalytic converter installed, even with bigger piping.

If backpressure was needed to make power then I would be a millionaire for designing a plug to seal off the end of the exhaust pipe.

93Toyota PU

Low back pressure does build top end power...thats why most drasters just run header pipes and earplugs! However, from what I've read, some back pressure is needed to produce low end power and torque...which is what most of us need in our daily driving. It's also been pointed out to me that too little back pressure can result in premature scavenging of exhaust gases from the combustion chamber. This results in unburned fuel gases being exited out the exhaust prematurely, instead of being burned for power. Sounds like a good way to reduce your MPG. Of course there are a lot of factors such as cam specs, timing etc. Just my 2 cents on a highly complex topic.

userJURKO14

drift crew defiantly arrows on the road take the toll not people fault about digital power xoOox
!()(

ewong

a quick Google on the web... and I learn

A "fake" box would generate a cycling voltage between 0.10v and 0.90v

Cycle Rates
Engines with throttle body injection are somewhat faster (2 to 3 times per second at 2500 rpm),
while engines with multiport injection are the fastest (5 to 7 times per second at 2500 rpm).

I have a meter on mine - I recall 2-3 times per sec

IMHO - Far easier and cheaper is to weld a bung on the tail pipe and insert an 02 sensor....

The second 02 sensor is used by the ECU to determine the functioning of the CAT.
So, not only does the second sensor have to have a proper signal, it has to "match" the signal and expected modified values generated by the FIRST O2 sensor.

So, to really "fool" the ECU, your talking about making your own ECU to read
-- read the first 02 sensor
-- know what the CAT does to the signal of the second O2 sesor
-- Generate the second 02 sensor signal

It PROBABLY has to ALSO take into account
-- TPS signal - what is the load on the engine
-- RPM signal - what is the load on the engine
-- TEMP signal - what is the load on the engine
-- Transmission (gear in)
-- MPH - speed of the vehicle

as you can see- we are well on our way to building an ECU to FAKE OUT the ECU
At this stage - why not just use your NEW ECU instead of the OEM one - they you would not need the second 02 sensor.....

http://www.autotap.com/techlibrary/u...en_sensors.asp