cats or no cats

[llewis660]

02 gmc truck can you cut off the cats and not have it run like crap?

[Eroq]

nope, it'll run like crap, or constantly throw codes, and not to mention your fuel economy will go down the pooper

[Econo-box from Hell]

You can buy an oxygen sensor simulator that will fool the computer and everything will run as it should.  Modern converters are not very restrictive and I doubt you will see any performance gain even with the 02 simulators.

[7387chevynut]

I got a 95 chevy that has me wondering that when/if I have new exhaust put on it...........if I will have to have a new Cat converter installed.......truck has 200,000 miles on it

[damn_ford]

1996 brought on obd with downstream sensors, gotta keep cats after that for the most part.

good luck finding o2 sims, epa got wind of them and summit is no longer allowed to sell them

[Econo-box from Hell]

1996 brought on obd with downstream sensors, gotta keep cats after that for the most part.

good luck finding o2 sims, epa got wind of them and summit is no longer allowed to sell them

I did not know that.  Should be easy enough to build.  You just need a device that can vary an electrical signal from about 100mv to 900mv and keep the frequency slightly less than the upstream 02 sensors.

Like I said in an earlier post, I doubt you will see any performance gain.

[damn_ford]

it is my understanding that....

if you measure the resistance ofyour sensor at operating temp, you can simulate a working 02 by using the correct resistance in a loop\

[Econo-box from Hell]

it is my understanding that....

if you measure the resistance ofyour sensor at operating temp, you can simulate a working 02 by using the correct resistance in a loop\

The PCM looks at O2 cross count (number of times the voltage passes 450 mv) and voltage range (amplitude).  The PCM looks at the down stream O2 sensor and compares cross count and voltage amplitude to the upstream 02 sensor.  The PCM wants to see a drop in total cross counts coupled with a drop in amplitude at the downstream O2 sensor when compared to the upstream sensor.  This tell the PCM that the catylitic converter is doing its job.

[moose1229]

I had no cats on my 90 chevy that I built a few years aga.I had true duals w/flowmasters,I had altered the whole engine & drivetrain.I also de-computerized it w/old school 350

[2000silverado]

www.casperselectronics.com has o2 sims. they don't advertise them, but they do have them. email the tech and they will return your email With the part #

[Norm Henderson]

you can cut it off only if there is not a O2 senser after the cat

[Fraser]

1996 brought on obd with downstream sensors, gotta keep cats after that for the most part.

good luck finding o2 sims, epa got wind of them and summit is no longer allowed to sell them

i dont remember, but those might have been listed as 'for race only'  but if there already gone, there already gone

[Fraser]

www.casperselectronics.com has o2 sims. they don't advertise them, but they do have them. email the tech and they will return your email With the part #

which one is the tech? john or justin? or sales haha

[camok10]

my 97 has cats cut its the bigest pain in my ass because the previous owner did it and also took out the check engine light to fix it being on all the time 

but all you need is a resistor to drop the 5v refrence down to about .450 to .5 v.  since it is post cat it will be fine because it should be a steady voltage any way( if the cats are functioning properly it will read steady )   

[camok10]

but all you need is a resistor to drop the 5v refrence down to about .450 to .5 v.  since it is post cat it will be fine because it should be a steady voltage any way( if the cats are functioning properly it will read steady )  

That is not the case...the sensors in the engine system go by pulses to tell the computer the sensors are working. 



Read what Econo said

pre cats do the pulse with the rich/ lean throb , but post cats read steady hook up a scope to one and read it it will be about .45v - .5 and read steady 

maybe econo can re phrase what he said to me if im wrong

[2000silverado]

www.casperselectronics.com has o2 sims. they don't advertise them, but they do have them. email the tech and they will return your email With the part #

which one is the tech? john or justin? or sales haha

lol i wrote them all i also found
http://www.afterthoughtsauto.com/o2sim.html