How much back pressure out the exhaust?

[Shandley]

How much pressure should be coming out of the tail pipe? I guess what I am asking is how do we know if our cat's are plugged?

[Pete M]

only way I know is to pull the cat and shine a flashlight through it. :dunno:

[Shandley]

Is it... *GULP*... easy to do?

 

When I first started my truck after about 5 years of sitting, I noticed pieces of rust firing out the tail pipe (there is a straight pipe with a cat, no muffler). Mind you it took a bit for it to start coming, it's not coming out anymore, and there is still a good amount of exhaust coming out... think it's worth it?

[Pete M]

I've never done it, only heard of it.

 

do you have inspections or sniffers in your area?

 

still running the stock exhaust?

[mvusse]

When the cat in my Suburban was mostly plugged, the truck jumped away from a still stand like a jackrabbit, then immediately stumbled, and was fine after that with more gas. Gas mileage was down the drain also (and it never is good to begin with in a Suburban...). Once it plugged up completely I could not keep it running, but I should consider myself lucky I didn't blow up the exhaust manifold or Y pipe.

 

The flash light trick is a sure fire diagnosis, but the cat may be welded on. Even if it's bolted with a flange adapter, the bolts are probably rusted.

[Wildman]

5 years of sitting...... :hmm:

 

I would think condensation took it's tole on it :(

 

I know parts are hard to get way up in the far north.......but, it might be time for a complete exhaust system.

 

If your beyond the sniffer test, then just delete the cat, and run a muffler, But.......your gas mileage will suffer some.

[Shandley]

Thanks for the reply.

 

I'm not really concerned about the gas mileage but the aircare I am worried about.

[FxRacing282]

if you can hold your foot to the floor for a while and it does not stall or die then don't even bother pulling your cat off. your just wasting your time. if you run open exhaust your mileage and power will be in the toilet and you will suffer. cat's do not fail often in the sense they clog up, they usually just become inefficient.