gee

Ive got a friend that wants to remove his cats,but i was unsure weither or not he would have issues with the 02 sensors acting up and making the truck run like crap.Do you remove them as well?Its a boss 5.4l truck if that helps any..

MU71L4710N

he will have to buy some MIL eliminators, they are around 50 bucks and they plug in between the 02 sensor and its harness and prevents any codes from bieng thrown.

Colorado_Mustang

The O2 sensors that dictate engine performance would not be affected. The cat performance monitoring sensors after the cats will throw a code that puts the computer in an open loop mode, which degrades performance.

The only thing the computer is looking for is a resistance signal from those sensors to determine how well they are working. You can spend $50 for something that is becoming harder to buy due to federal emission laws, or go to Radio Shack and get a couple resistors that are the right size. To find the right size, see what the computer is reading from the sensor with everything working properly.

gee

Thanks for the info, but he does have 4 cats and 2 02 sensors, does that mean he will have to buythe eliminatorsfor allor just thefront one?

gee

Hey Colorado mustang I had a 71 Mach1 till i totalled it, Is that a 71 or 72 you have? Man that was a big car, But very fast

Colorado_Mustang

My Mach's are 71, 72, and 73. The one in my sig is a '71 Grande coupe.

The only place you want eliminators is on the back O2 sensors. Placing them on the front sensors can harm the engine as you will likely not get the loop response correct and can over-lean the engine mixture.

gee

thanks for the info, If I wanteddelete my catswould I haveto do the same on my 03 gt ? and would it pass emissions if they didnt notice they where gone?

Colorado_Mustang

Yes, you would.

If they look under your car with a mirror, you will fail. More places are doing that because of the
prevalance of off-road exhaust systems on performance oriented cars.

In reality, using an aftermarket H/X-pipe with cats is not detrimental to performance.

gee

Thank you, Ill pass it on