Remove cats or keep them? chime in.. asap

[918hatch]

So I am pretty sure one of my cats took a dumb on me.. One of them is damn near new and the one that took a dumb well.. is old. Should I just buy another or take them both out? If I do take them both out what do I need to do so that my CEL wont come on. How will it run? Let me know. this is on the truck in my avatar.

[BigChevy17]

imo taking them off will make the truck sound so much better
plus the price differance between a cat and two peices of pipe is pretty big
but its up to you
what muffler are you running

[Underpowered]

if you take them out, your CEL will come on. to solve that you have to have your rear O2 sensors turned off in your computer via a tune. or buy some O2 simulators that will always send a good signal to the PCM.

how much did it cost to have the one replaced? i know when mine went bad shops wanted an outrageous price to replace them. $300 each to buy and install the cats. Personally i would say keep em. they help if you ever plan on getting rid of the truck, as most dealers will not take it in on trade if they are removed.

[918hatch]

it cost like 320 thats why im tryin to do this plus im not goin to be tradein in i hate to have payments thanks and how would i turn off the rear 02 i have one of those code readers for the cel i wounder if that could do it?

[918hatch]

its an actron code reader and where could i have that 02 turned off

[elsurfo10]

i did it in my 93 burban and its sounds really good and no cel is on but it only cost me 5 bucks for a pipe and 6 bucks for clamps and i was set. its alot cheaper than new cats thats for sure

[Underpowered]

you actually have to have your computer re-tuned. a code reader will turn the cel off, but it will come right back on as you can't re-tune the computer to actually turn the O2 sensors themselves off.

well i would cut the cats off and buy a tune then. i bought headers when my cats went south as it was about teh same price, then spent $200 on a tune from blackbear.

[Underpowered]

Originally Posted by elsurfo10

i did it in my 93 burban and its sounds really good and no cel is on but it only cost me 5 bucks for a pipe and 6 bucks for clamps and i was set. its alot cheaper than new cats thats for sure

your TBI engine in alot different than his vortec. you only have one O2 sensor in the drivers side manifold. his truck has 4 O2 sensors. one in each exhaust pipe before before the cat and one right after on each side.

[918hatch]

Originally Posted by Underpowered

you actually have to have your computer re-tuned. a code reader will turn the cel off, but it will come right back on as you can't re-tune the computer to actually turn the O2 sensors themselves off.

well i would cut the cats off and buy a tune then. i bought headers when my cats went south as it was about teh same price, then spent $200 on a tune from blackbear.

How much does a basic tune cost? Is $200 a normal price for a base tune?

[88Vic]

I would cut the cats out, sell the good one and buy Thunderbolt highflows, which flow as well as a straight pipe and are cheap, like $50 each for ones with O2 sensor bungs. Then get an ECU tune from BlackBear anyways since it's well worth it.

[elsurfo10]

yea mines EFI but yea thats why i stick with the old less problems... sorta hah

[Josiah Dozier]

I bought a one chamber flowmaster for my truck and wasnt pleased at all till i removed the cat now it sounds amazing. You should definately take the cat off.

[xsbchevy]

for $500 you can get the complete cat forward from a dealer installed.did it at a dealer had mine done when the passenger went out and caused a fuel pump burn out.
the muffler shop that i go to for work says the cats on the nbs are of equal quality to a highflow. the bricks are better made than the obs.


btw the dealer said the life of the stock cats is about 80k miles.

[Underpowered]

Originally Posted by xsbchevy

for $500 you can get the complete cat forward from a dealer installed.did it at a dealer had mine done when the passenger went out and caused a fuel pump burn out.
the muffler shop that i go to for work says the cats on the nbs are of equal quality to a highflow. the bricks are better made than the obs.


btw the dealer said the life of the stock cats is about 80k miles.

um, dealer here wanted over $600 just for parts. no idea on what they would have wanted to install.

and a bad cat won't cause your fuel pump to burn out. the cat going bad has nothing to do with the fuel pump at all.

as for tune price. blackbear is chargin $250 now i beleive. but just search around, many tuners out there in many price ranges.

[xsbchevy]

the cat has a lot to do with it. if its backed up the rear o2 wont read properly. o2's have control over the lean/rich mix. if it says ok im getting to much fuel i need to trun back the mix and vice versa. the way the dealer mech explained it is the passenger side was fighting over fuel mixture and threw the pump for a loop. it didnt kill it totally but it screwed up the fuel pressure. when mine went bad i would top out at 50 then slowly drop to about 10. id kill it set for 5 min and do the same thing again. i was getting about 10-15 miles before it started doing it again

[Underpowered]

i know the O2's detect rich/lean conditions. but the fuel pump does not modualte the pressure, as the rich/lean conditions are corrected at the injectors, not the pump.

[xsbchevy]

i did some searching after i posted the last one your right. but if i had all 3 injectors on one side going full it could cause fuel pump problems wouldnt it. like i posted the guy at the dealership explained it to me that way. so i assumed he knew what he was talking about.

[Underpowered]

Originally Posted by xsbchevy

i did some searching after i posted the last one your right. but if i had all 3 injectors on one side going full it could cause fuel pump problems wouldnt it. like i posted the guy at the dealership explained it to me that way. so i assumed he knew what he was talking about.

the first problem is you assumed he knew what he was talking about. just cause they are at the dealer, by no means they know what they are talking about.

but the pump will pump at a constant rate, so whether at an idle or at WOT your pump is pumping the same so it does not matter if one cat is clogged or not.

[918hatch]

Thanks for the replys guys.. It was something in my tranny not the cats..