Hi Guys well tonight i dropped the cat out of the exhaust system and look what i found.
The Good End


The Bad End


What Came Out


Could this be the cause of my terrible fuel mileage. 19L/100km's (~12.38 MPG i think). What else would this affect?

Thanks

 

The cause of the terrible mileage? Probably not, unless the other catalyst block is really clogged up. But you can easily find out by putting it back on half hollowed out(remove the broken catalyst block bits and run with just the one). Or buy installing a new one and seeing if that makes a difference.

What else would it affect? The loudness of the exhaust, it's probably louder than stock now(or will be if installed half empty). But it could potentially be less restrictive and improve engine performance slightly too, with all the broken catalyst debris cleaned out.

BTW, what the hell happened to it. It looks like you took it off and ran over it.

 

based on my very recent experience, bas gas mileage is going to come from your tps. some people say your o2 will also affect it, but in my case, changing the tps and properly adjusting it solved the whole problem

 

I Am dropping the cat all together and replacing it with a 2 1/4 inch pipe, that was actually the original reason for taking the cat off because i wanted to remove it.

Honeslty i don't know what happened to it, about 2 months ago i had extractors fitted to it and it came back from the exhaust shop in bad shape eg, bolts not done up, half the hoses hanging off, running like a dog, they snapped one of the add vaccum solenoid switches so i don't have 4WD at the moment (have ordered a replacement of evilbay waiting for it to arrive). So i am wondering if they F***ed the cat too.

I think i will still replace the o2 sensor but i want to see what difference just the cat makes first, is the TPS difficult to test?

 

not really. its a potentiometer so you need to test the resistances between to pins at WOT and a couple other positions. i cant remember off the top of my head. but there are tons of threads detailing the step by step. you just need a multimeter.

 

Great, thanks, i think i should be able to handle that haha. might give it a go tonight Just had a quick look at the repair manual and it details measuring resistance between pins in the TPS

 

good deal and good luck. remember if any of the resistance values are off the sensor is bad so go ahead and replace it. your wallet will thank you

 

Your O2 is easy to check as well, and greatly affects mileage if bad. You may need an analog voltmeter to test the voltage jumps on the check connector, but it only takes 5 minutes. Check the FSM on TTORA for procedure. Rockauto.com sells Denso O2s cheap.

 

@MudHippy: What other catalyst are you talking about? It's a monolithic converter: all the catalysts are embedded in the matrix.

A converter, with a burned up and blocked matrix WILL cause excessive restriction in the exhaust path and WILL cause degraded fuel economy, due to either the solids blocking exhaust flow or the exhaust flow being blocked by solids.

@StampyDH- a shop can install a temporary "test pipe" to determine if the converter was causing excessive restriction to the exhaust path. Mind you, though, that they can't leave the test pipe installed permanently so the converter will require replacement. The issues come to: what caused the converter to overheat and burn up resulting in the fragments you were able to dump out, and what needs done to prevent that from happening with the new converter you'll likely be required to install.
Realistically speaking, it's an over-rich fuel mixture that causes a converter to overheat and consequently "grenade" itself. That would indicate either incorrect ignition timing, incorrect valve adjustment(s), incorrect throttle or air flow sensor signals (clogged air filter even), faulty lambda (O2) sensors or possibly excessive restriction in the exhaust / muffler (for whatever reason).

 

The precious metals in the guts of that cat are probably worth well over $100. I sold my old 3.0 cat to a metals recycler for $140 cash and it was 13 years old IIRC.

 

As far as I understand, clogged CATs mainly cause power loss right? (because the engine is unable to pass the proper amount of airflow through the engine to generate normal power.

However, I'd chase down what caused the CAT to be clogged in the first place. That is your more likely source (as mentioned above... sensors and things like that).

 

Who said anything about it being clogged?

Hint: This isn't a post count contest newbie. Nothing relevant to add? Then please don't clog threads with your posts.

 

You are correct- it's not a post count contest. Were it that, I've got you trumped with high spades.

Take your own advice, MudHippy: if you've nothing relevant to add, don't clog the thread.

Let's be civil / respectful and respect what others post. If you can't be civil / respectful, don't post.


No one said anything about it being clogged. However, considering the photos the OP posted of the "bad end", it's obvious something was clogged otherwise the converter wouldn't have overheated and blown out catalyst ... right?

 

Wow I didnt know the stock cats were worth over $100. I think im gonna sell mine and replace it with a high flow cat, larger piping and muffler

 

That's exactly what I did, the replacement 2.5" highflow cat was only $60 on ebay.

 

Well take it from me...over x-mas while my wife was at bKohls shopping some low life cut the converter off her truck. Its a 1990 4X4. Luckily they didnt cut the o2 sensor or screw it up too bad...BUT...still cost 250.00 to have fixed.

 

Yep, sell it before someone else sells it for you.

 

That would be you.