FIRTH4X4

I've done some searching here on the forum, and on the web, have found quite a few "off road" cat deletes, but none for the 2002 dual cat 3.4L tacos. Anyone know of any? Otherwise, I am going to unbolt at the stock Y pipe and unbolt behind the last cat. Have a muffler shop build a pipe to fit in there and bolt back up, with both the 02 sensor bungs welded in, just straight pipe though no cats. Will the rear sensor start throwing codes? Would like to just leave it in there instead of buying a sim from URD.

And this is my first post here, have owned many Toyotas over the years, love em!

INFINITY

why would you want to get rid of the cats? power? if they are not burned up or clogged leave them there.

that system uses 2 o2 sensors and yes you will throw a CEL. this will cause the ecu to run in safe mode and you will loose power.
keep them

vital22re

iTrader: (2)

yes you will throw codes. My advice, leave it alone. It is against the law to remove cats from vehicles that came with them if they are driven on public roadways. Its your rig so you do what you want. If you dont' want codes you'll have to get the rear o2 simulator.

FIRTH4X4

So if I sim the rear sensor I should be OK? Cats plug up over time, they are a wear part, don't last forever. Here in podunk Idaho there are no emissions. I know there are other guys looking for something like this, if it works well maybe I'll sell some.

FIRTH4X4

Are there any ways to test cats flow without physically removing them? Yes this is the reason, more power, and less fire hazard in the woods and fields.

mt_goat

LOL, yeah. It will throw a fit just removing one of them, both forget about it.

JamesD

Today's catalytic converters are not that restrictive so I would leave them on.

James

FIRTH4X4

I thought the front sensor is what the computer used to determine air/fuel and the rear sensor was for emissions purposes?

FIRTH4X4

Thanks for the reply James. This seems to be what everyone keeps telling me. Guess I need to rethink my bias about cat converters. But does anyone else farm? Those puppies get hot, don't want to burn down a grain field.

INFINITY

they mainly get hot and stay hot if they start to get plugged. if you look down the exhaust tube it will have the look of a screen door (small square cores). very easy to see if they are plugged or melted.

mt_goat

You asked if the rear sensor would throw a code...YES! P0420.

FIRTH4X4

K thanks. Will get the URD sim for it. Can't wait to do all new exhaust just need to choose a muffler now.

TheDurk

Yes, you will throw a P0420. Or a few others (e.g. P0141) if you just leave off the rear sensor.

NO, you will NOT go into safe mode or have any effect on performance from a P0420. On my '99, the only DTC's that trigger a safe mode are P0100, P0110,P0115,P0120, P0135, P0141, P0325, P0330, and P1300. The safe mode is different for each code. For example, the only effect of P0135 and P0141 is to deactivate the associated sensor heater circuits. (Other codes would probably result from a dead front sensor, however, in the case of P0135.) See Page DI-164 ('99 FSM) Vol. I.

I agree it is better to leave the cats, I just wanted to correct the information on safe mode as many have this erroneous belief. There are probably some other safe modes for the throttle-by-wire years--these are from '99.

4runner joe

let me know how it goes im goint to build my on pipe aswell because the cat is clogged and he i just dont have 700 dollars to throw at two new cats. lol so im going to run a new pipe with a after market cat and both o2 sensors aswell. hope mine works if not a damn waste of money!

Greasepatchworker

I've got a 96 Taco with the 3.4L wanting to delete a single cat delete because it only has a single and I'm wondering if I cut out the sensors out and weld them into a straight pipe will it throw a code or run poorly?

wyoming9

iTrader: (1)

The sensors read the converter efficiency if you remove the cat it will trip the MIL

Why would you want to remove your cat??

Malcolm99

And yes you will lose power and run poorly and have bad gas milage.

thefishguy77

iTrader: (1)

Leave it alone unless you have a plugged cat. Then replace it wth a new cat. They are not an older chevy or first generation cat system. Environment aside you motor is designed to run with a certain amount of back pressure. This back pressure actually helps evacuate exhaust from the motor more efficiently. By removing the back pressure you can actually hinder your rigs ability to produce power.

Now if you are building a dedicated off-road machine and have built a motor to run on the least amount of components possible then sure go ahead and delete it. But to remove it for the sake of removing it will do virtually nothing for performance for you.

I wanted a less restrictive exhaust on my 85 22re and it came with a plugged cat. So I put a header back 2 1/4" exhaust with no cat and a magnaflow on it. Seemed flat so I bought a hi-flow cat and welded it in place. My throttle response is much better now and mileage went up. Proper back pressure even on a 31 year old motor. Not harping on you just trying to get the point across that there is zero benefit to removing exhaust components for a street ride. In fact it can result in a ticket.