I want to remove the rear cats on my 1999 F150 5.4, strictly for sound purposes. yeah yeah I know it's illegal, I really don't care. but I don't want a check engine light, should I do?

 

You add a non fouler plug that the O2 sensor will go into to trick the PCM into thinking converter is still there.

 

That does not always work.

 

Non foulers are more for the hacks with leaky Y pipes. Plus they screw your AF's up and cut into your economy. The engine will no longer run as good as it should. If you don't care about that hack away.

It's not illegal here btw.

If you want to do it correctly, replace the rear cats with a straight pipe but make your connections tight. If they are tight and don't leak terribly, you won't get a CEL.

 

I have read that insurance companies will not pay out in instances where cats were removed and they had reasonable suspician that the cat removal was to blame.

Other than sound...are these cat removals really worth the effort brew? Performance wise I read they add nothing.

 

Yep, just sound, for those who like that sort of thing lol.

 

[QUOTE=Hammer Mechanic;5330167]I have read that insurance companies will not pay out in instances where cats were removed and they had reasonable suspician that the cat removal was to blame.

What insurance company's won't pay out, with a removed cat? Are you talking about the ones who do engine/trans type insurance? That would be the only ones I can see doing that. If you had a newer vehicle the manufacture would void your warranty, but car insurance? I'm confused.

 

Agreed.... need moar explanation.

 

I had been curious about cat removal a few months back. When I clicked on one of the links after googling...I cant remember the site...they went on and on about it being illegal. They also mentioned a case where a guy had an engine fire and when an insurance adjuster found the cats removed the insurance company refused to pay out. I never heard of it before either but the site said it can and does happen. I just tried googling again to provide the link but it isnt coming up. Maybe it was more fake news...it was around election time.

 

They are illegal to modify in any way in California. Perhaps other states as well.