Clogged Catalytic Converters - FJ Cruiser

[Nick1994]

This is on my dad's 2007 Toyota FJ Cruiser. 4.0L 6 speed manual. About 111k miles

He has for several years expected the catalytic converters were plugged on his FJ. Low power, it is pretty gutless! It does somewhat ok if you get on it really hard high up in the RPMs but it has always been so gutless. Driving up mountains gives off the classic rotten egg smell, bad! He called me today and said he finally got around to cutting them off, he said you almost couldn't see through them looking at the sun. He showed a mechanic at work and he said they were toast. My dad pounded the internals out and welded the catalytic converters back on and said it is a night and day difference, loads of power!

I'll have to see it myself. I'll drive it tomorrow (he lives out of town).

What can cause this? It's been like this for years. It calls for premium gas and he usually runs 87, but sometimes springs for 91 octane. He also drives it like a granny usually and short trips it. But it does get warmed up often on longer drives.

Anything he can do to prevent it from happening again? Everything on it is original. It is due for spark plugs.

 

[Dorian]

Interesting. I can't imagine that the cats would be that bad so early on. My grandpa had a bad cat in his 05 LaCrosse. He drives very gently and takes long highway trips. So it's a similar situation. However, I am very envious of his FJ. Hopefully there will not be a consistent CEL on.

 

[Wolf359]

Sounds like there's more to the story. If they were plugged up, there was probably a CEL light that he ignored. Bad O2 sensors, misfires or a vacuum leak. I went over 200k in a car with the original cats. They're supposed to last the life of the car if everything is operating properly. Federal emissions is normally 8/80k but that can vary from state to state. For emissions purposes, a Pzev car is great if you're in a Pzev state, 15 years/150k on emissions related items and that includes cats and fuel tanks.

 

[Bottom_Feeder]

So he's going to replace them, right?

 

[Ramblejam]

1. There are four catalyic converters on the 2007 FJ Cruiser. How did he determine which one was at fault?
2. This is an OBD2 car; hollow out the cat, and you're going to throw a code. It'll run open loop, and while it's better than a clogged exhaust, it's not going to run like it should.
3. http://www.myazcar.com/testing-info-and-fees. He will fail.
4. If he could remove/weld these, he could have installed brand new cats. Dumb move.

 

[dishdude]

Originally Posted By: Nick1994

Anything he can do to prevent it from happening again?


Originally Posted By: Nick1994
My dad pounded the internals out and welded the catalytic converters back on and said it is a night and day difference, loads of power!



I don't think it will happen again.

 

[mclasser]

Originally Posted By: Wolf359
Sounds like there's more to the story. If they were plugged up, there was probably a CEL light that he ignored. Bad O2 sensors, misfires or a vacuum leak. I went over 200k in a car with the original cats. They're supposed to last the life of the car if everything is operating properly.

+1 Cat failure is almost always a result of some other problem.

 

[Chris142]

Originally Posted By: mclasser

+1 Cat failure is almost always a result of some other problem.
this! Something caused them to burn up.

 

[mehullica]

That engine has plain copper spark plugs that are required to be replaced every 30,000 miles as the owner's manual states. See if you can borrow a decent scan tool & check your "knock lean value" I'm sure you have tons of carbon build up with poor spark with these old plugs

 

[Nick1994]

It's never thrown a code before. He drove it around today and nothing yet. Tomorrow is a 250-300 mile trip so if it throws a code it'll likely do it tomorrow.

He'll replace them someday. He lives in a county in Arizona with no emissions.

 

[RedOakRanch]

My coworker had the same thing happen on a 2000 dodge 1500. He punched out the cat reinstalled it and it passed the CA sniff test a year later. He does not plan to replace it.

 

[Gasbuggy]

The second set of cats might keep it from throwing a code.

 

[DoubleWasp]

Failing an emissions test is not a guarantee. I passed NY emissions with quite a few cars that had no cats. A few people I knew passed with a full heads/cam/exhaust package with no cats.

The CEL caused by catalyst efficiency below threshold does not cause Open Loop running in any vehicle that I am aware of.

Clogged cats cannot be caused by misfiring or engine drivability issues. That causes cats to melt down, not clog.

The only thing that can cause a clogged cat is some form of oil burning, or a loss of catalyzing effectiveness (low quality converters).

 

[Gasbuggy]

They passed because of tuning software turning off the O2 monitors.

 

[gathermewool]

Originally Posted By: DoubleWasp
Failing an emissions test is not a guarantee. I passed NY emissions with quite a few cars that had no cats. A few people I knew passed with a full heads/cam/exhaust package with no cats.

The CEL caused by catalyst efficiency below threshold does not cause Open Loop running in any vehicle that I am aware of.

Clogged cats cannot be caused by misfiring or engine drivability issues. That causes cats to melt down, not clog.

The only thing that can cause a clogged cat is some form of oil burning, or a loss of catalyzing effectiveness (low quality converters).


Agreed. The Open/Closed loop transition is based on the upstream O2 sensor(s) (for information, my older Subaru used the down-stream O2 sensor as an input for fueling, but did not affect OL/CL logic, as far as I know. Other cars may use different logic). When the sensors are warmed up, the ECU will command closed-loop.

A structural failure in the cat (manufacturer defect or mis-firing) can cause failure, as well. I don't know the arrangement of the cat the OP's dad gutted, but is it possible that post-combustion due to poor spark and too-low octane might be the cause?

//

OP, regardless of whether the new setup causes a CEL, it's not ideal. Newer cars are a little more sensitive than older cars. The additional flow through the gutted cats may result in excessive knock, which could damage pistons/rings, valves, etc. The variable valve timing, ignition timing and etc. are not tuned for his current setup and will not work optimally. I know older turbo Subarus (I have in mind 2002 WRX) were VERY forgiving to not tuning, but don't know of many modern cars that can be without tuning the ECU for the new setup.

At the very least, he should be using nothing but premium fuel now.

 

[DoubleWasp]

Originally Posted By: Gasbuggy
They passed because of tuning software turning off the O2 monitors.


No. Spark Plug non-foulers.

 

[Nick1994]

Saw him today, met him out in the desert for some off-roading.

He gutted the rear catalytic converters on each side (it has 4). He did it because they were behind the oxygen sensors. No CEL codes, runs fantastic. I took it for a spin, drove it like a race car on the dirt roads and it is absolutely incredible the difference. It really is a night and day difference. At 15 mph when flooring it in 1st gear, in 4 wheel drive, it starts "burning out" all the tires, there's no way it could have done that before.

 

[mehullica]

The 2 rear cats are not monitored, the front cat is part of the exhaust manifold & is the only one monitored. The rear ones can be eliminated & it will not throw a code.

 

[supton]

Originally Posted By: Nick1994
What can cause this? It's been like this for years. It calls for premium gas and he usually runs 87, but sometimes springs for 91 octane. He also drives it like a granny usually and short trips it. But it does get warmed up often on longer drives.

Anything he can do to prevent it from happening again? Everything on it is original. It is due for spark plugs.


Guessing it is running rich to keep out of detonation--maybe not at idle, but certainly under load. Old plugs may not be helping at this age either, but I'm guessing it's from running rich.