Gutting Cats

[thieaux]

Guys since i live in a country where theres no emission controls, could i gut my cats since i think there blocked and not get a cel.

Does someone have a step by step proccedure.

I have a 91 ls400

[GRAND_LS 4]

Guys since i live in a country where theres no emission controls, could i gut my cats since i think there blocked and not get a cel.

Does someone have a step by step proccedure.

I have a 91 ls400

You want a step by step procedure on how to gut the cats?

[bartkat]

As a cat lover, I'm afraid this just can't be tolerated.

[thieaux]

JAJAJA Thanks guys for th response, Grandls to your question i dont need a step by step on gutting i meant if there was a way of cheting the ecu or is there something i need to do to o2 so i dot get a cel , cause i heard somewhere that if i gutt the cat i'll get a cel cause of the sub sensor.

And Bartkat i'm cat lover too bro .....happy new year

[95LS400Bob]

Remove each converter and look through it with a light at the other end. See if you can see through all the honeycomb type stuff and be sure none of it has broken loose and is rattling around inside the cat.

In the US it is against fed law to tamper with a cat converter. But you said you are in another country.

I would also think you will get a check engine light if you gut the cats on a 1995 and up..because there are 02 sensors that read exhaust after the cat. Not sure on earlier models.

[dcfish]

Remove each converter and look through it with a light at the other end. See if you can see through all the honeycomb type stuff and be sure none of it has broken loose and is rattling around inside the cat.

In the US it is against fed law to tamper with a cat converter. But you said you are in another country.

I would also think you will get a check engine light if you gut the cats on a 1995 and up..because there are 02 sensors that read exhaust after the cat. Not sure on earlier models.

Why don't you just remove the cats?

[ArmyofOne]

Remove each converter and look through it with a light at the other end. See if you can see through all the honeycomb type stuff and be sure none of it has broken loose and is rattling around inside the cat.

In the US it is against fed law to tamper with a cat converter. But you said you are in another country.

I would also think you will get a check engine light if you gut the cats on a 1995 and up..because there are 02 sensors that read exhaust after the cat. Not sure on earlier models.

Why don't you just remove the cats?

thast what i would have said. more perfoemance if you gut them completely. to eliminate the CEL, i believe you can "piggyback" the circut so it reads from an O2 sensor on the manifold...PM Toysrme abotu that.

[SRK]

91 and up LS engines utilize post-cat O2 sensors, whose job it is to check the function of the cats themselves. They have essentially a flat response voltage, unlike the pre-cat sensors which produce a fluctuating response across the stoichiometric point. The ECM must see a particular waveform from the post-cat O2's otherwise it will set a code. On some high performance cars like the LT-1 GM engine it is possible to install O2 simulators, which produce a signal that mimics that of the operational post cat O2's. I cannot imagine that the GM sims will be close enough to the Toyota signals to fool the ECM.

Check the cats and replace them if they are damaged. That will help maintain the proper fuel trims at all times, for power, mileage and emissions.

[SKperformance]

You can make or buy an o2 simulator ,it is as SRK said it is only a resistor that makes the ecu think it is working in the right parameters.

The first 2 o2 sensors create an algorithm which the cat is supposed to flatten .So the last sensor just makes sure it is flat and not fluctuating.

[thieaux]

Thanks Guys , Sk if the main ones make an algorithm that the cats is suppose to flaten , and the sub checked on it , im assuning that they depend on each other, i mean if the mains are bad they could trigger a cel for the Sub ore the other way around, since i dont have any cel , im not gonna worry about it.

Another thing , what do you think about my plam of leaving the subs, disconnecting them under the carpeting and apllying the resistor right there on the ecu side of the plug ,, does anyone know the values of the resistence parameters on the SUBS not the main.

Thanks Guys

[SRK]

O2 sensors do not provide a resistance, they generate a small voltage in response to the oxygen content differential from reference air and the exhaust gas. Just how one duplicates that with a sim I don't know.

The voltage variation of the pre cat sensor produces a fuel trim which keeps the engine within emission standards, but the swing from rich to lean also provides the molecules the converter requires in order to go from reduction to oxidation reactions, and allows one convertor to deal with the three main exhaust gases effectively - what is known as a "three way catalyst". The post cat O2 sees exhaust gas at a constant O2 content, and should therefore produce a nearly flat response line, indicating that the cat is doing its job.

Trip a code, from either the pre or post cat O2 and the ECM will revert to programmed values, not feedback closed loop values, and the engine will run poorly, in addition to tripping the cooling fans and disabling the traction control.

It ain't worth it.

[thieaux]

THanks bro, ur probably right , its not worth it , its just that i have no power afetr 3500 and thought it could be th cats , since im not getting any cel or stored codes in the ecu.

Well thanks anyway , ill keep looking for the problem