Hey all,

Sorry to double post, but I want opinions.

How bad is catless on a discovery 2? My cats got stolen, and I got straight pipes put in last year. Mufflers are still on. It's a bit loud on startup, but once the engine is warm I really enjoy the sound.

Recently took it to a mechanic to get Three Amigos Cleared (lost traction on the highway), and he right away noticed a 'slight misfire' and said I'm damaging the engine.

It does foul up the 02 sensors fairly quickly if I do only city driving, and throws a code. But it manages to stay code free if I do some highway miles.

The head gaskets are pretty much done at this point, so my plan is to do them in the spring, and check on the spark plugs and see how everything looks, then decide if I want to put cats back on.

The questions I have for you is, is there anything else I should look out for to see how things are behaving catless? If I must put cats in, any recommendations? Anything to just add backpressure prevent her from running rich? Obviously passing emissions is no problem for me....

Please keep the preaching about toxic fumes to a minimum... I drive twice a week maximum in one of the dirtiest cities in the world with an insanely high level of catalytic converter theft.

 

no issues. Been catless for almost 4 years now after mine got stolen. No codes just noisy

 

Yeah, your issues with fouling the plugs is likely due to something else like maybe the head gaskets or something

 

Been catless for years. Installed cat foolers on rear sensors.

If I ever replace the exhaust system I'll move the down stream sensor bungs to the top of the pipe instead of below. The cat fooler adapters fill with soot over time. So far I've not had a failure.

I don't notice it being loud, but all our other vehicles are diesels, one muffler between the three of them.

 

Tell me you live outside of California without telling me you live outside of California, haha.

 

I'm extremely thankful I am in a non inspection state.

 

Yeah okay then it's probably this. I'm fouling O2 Sensors but that makes sense the head gasket would do that. I lose about 1/3 of a jug of coolant every fill up or so at this point, so she's due. No forbidden milkshake or coolant coming out of the exhaust, it's just all from the weep hole so I've been driving. The expansion tank cracked and I lost all my coolant, thankfully I have an ultragauge and shut the engine down when temps climbed above 215, so no catastrophic failures, but it seems to have been the final knockout punch for this head gasket to need attention.

Good to know plugs fouling could be head gasket issue too! A mechanic in Astoria pushed me very hard to get the cats put back in, along with an entire engine reseal, saying my slight misfire at idle is from the cats and not just the head gasket, I politely declined. Thanks for the info

I hope to do the head gaskets myself, put studs in and do it right. I'm a hobbyist mechanic but trying to recover from a personal tragedy of doomsday proportions has turned this job from a fun project to an overwhelming ordeal.

 

I would replace the water pump to make sure that it’s not your whole leak before delving into the HG’s.
HG’s are a fairly big job, but nothing really difficult. Just a lot of relatively easy steps.

 

Plugs fouling from no cats doesn't make a lot of sense. Fueling is controlled by the upstream sensors and the downstream sensors are primarily there to determine the effectiveness of the cats, but they won't make the engine run differently. I'd add a new mechanic to the parts list when you look into the headgaskets. This one seems to like the Astoria shuffle.

 

TBH yeah I should iron down the leak myself, the mechanic tried to show me it was from the head gaskets but I'm not 100% confident I believe him. Plus with all his upselling....

I'll read more into tracing leaks myself. Any quick tips are appreciated