Dual cat 99 Cali 4Runner

[Yukute]

Dual cat 99 Cali 4Runner

Hello,

I am now in Colorado and have a California version with 2 cats on it. I am throwing an engine code that says I have a bad cat but not which one. They cost $750 and $950 each.

My question is:

Can I just run the rear cat and replace the front one with pipe?

Or will this throw the computer into a brain freeze?

 

[TheDurk]

Dual cat 99 Cali 4Runner

Hello,

I am now in Colorado and have a California version with 2 cats on it. I am throwing an engine code that says I have a bad cat but not which one. They cost $750 and $950 each.

My question is:

Can I just run the rear cat and replace the front one with pipe?

Or will this throw the computer into a brain freeze?

You will see P0420 and a CEL until the end of time but the truck will run just fine. You will never pass an emissions test, but that's Denver only in Colo., isn't it? But what's the advantage of the pipe?

 

[PhdNPrerunners]

Just replace them with 2 universal cats. Just because it is from California doesn't mean you have to use California legal cats

 

[Yukute]

Thanks for the reply.

As long as it doesn't effect how the engine runs I can live with it. I can pass the emissions test by disconnecting the battery for 5 minutes just down the street from the testing center. It takes about 20 miles for the engine lite to come back on. That's how I passed emissions last time.

Different counties have different emissions here.

As for the pipe I wanted to upgrade the exhaust system and run a single high flow cat and change the muffler.

 

[PhdNPrerunners]

Also before spending the money on the new cats I would check and make sure your o2 sensors are working. It is very common for the check engine light to come on and show a bad cat when it is really the o2 sensor that is not reading. Good luck

 

[Yukute]

Thanks again. It is appreciated.

 

[TheDurk]

Not that I care, but you should not be able to pass an emissions test by disconnecting the battery and then driving to the test. The ECU will return 'incomplete' until the test is complete, a minimum of two trips with some very specific parameters to be met about starting and stopping, engine temp, etc. Once complete, it can take a while for the P0420 to return, if the sensor(s) or cats are marginal. But definitely consider replacing your rear o2 sensor before ripping out what could be a perfectly good cat as PhdNPrerunners said.

 

[Yukute]

Thanks Durk.

Last smog check I drove to the test site, pulled over, disconnected the battery for 5 minutes, reconnected and drove the last block to the facility. It passed with fantastic numbers. May have been a fluke.

I will certainly start by replacing the rear O2 sensor as you guys suggest. With luck that will be the fix.

Thanks guys.

 

[99Yotarunner]

It could also be the front o2 sensor as i am having same trouble with mine right now, i have 150,000 miles on mine and im pretty sure its the origanal. i just replaced the rear one but light is still on so il be doing the front one next cause i highyly doubt the cats are bad.....time will tell... let me know how you make out.

Good luck

 

[RonMAIDEN]

How much are the front and rear sensors;I know one is an O2 and the other is a A/F mixture sensor and I think that's the one that is pretty pricey even aftermarket.

 

[TheDurk]

Thanks Durk.

Last smog check I drove to the test site, pulled over, disconnected the battery for 5 minutes, reconnected and drove the last block to the facility. It passed with fantastic numbers. May have been a fluke.

I will certainly start by replacing the rear O2 sensor as you guys suggest. With luck that will be the fix.

Thanks guys.

Sounds like they just did the old sniffer probe. Most modern facilities hook directly to the car's onboard computer through the OBDII port under the driver's side dash. One of the reasons is to stop people doing exactly what you did. Enjoy it while it lasts...and don't spend your money on a URD simulator. It won't work on a sniffer. It also suggests your problem is the sensor and not the cat itself.

How much are the front and rear sensors;I know one is an O2 and the other is a A/F mixture sensor and I think that's the one that is pretty pricey even aftermarket.

As far as buying, my oft-repeated advice is go here:Oxygen / AFR Sensors - Underdog Racing Development to get the correct Denso part number and then check around for the best price. That usually seems to be Amazon. A/F's in the vicinity of $100 and O2's around $60.