Catalytic convertor problems on my dually

the 7.4 in these trucks are dogs stock. gm put too much restrictions on them 4 sure. i reworked my entire setup piece by piece, and am happy with the outcome. i got the cam kit from summit, ford bosch injectors, removed airbox and built cold air intake, deleted cats, wait4me tune on the computer with all the torque management removed from the program, true duals with headers and magnaflow mufflers(all 3") and it is quite powerful and wayyyyy more torque than gm even imagined like it should be. it gets a little better gas mileage than stock, but it is a big block and not a honda i think even with an all stock truck, the tune is a much needed mod, especially towing the camper. later, brian

I took them off last night, one was ok but the other the stuff inside had broken into 2 pieces and had majorly deformed and was plugging off the exit, so I am confident that was my lack of power issue, don't know why it didn't trip the ces light but oh well, got me some straight pipe in there just need to weld it all up.

All this talk, now I am going to have to look under mine to see if I have O2 sensors after the cats...

it would trip the ces light if it had rear o2 sensors, but mine never came on when it happened to me either. okc, does your truck have supplemental restraints(airbags)? if so, it wont have the downstream o2 sensors. later, brian

Now I'm confused. In one post it seems like you're saying if the truck came without airbags it also came without rear O2's, and in the next one it sounds like you're saying the opposite? Maybe I just read it wrong. And I'm only half awake.

Anyway I don't see how the airbags would have anything to do with the O2's or why the truck would be equipped that way. Every 95-up I've seen that is a regular duty 3/4 ton or heavier came without air bags. I've heard some had airbags as an option but so far I haven't seen them. My '98 C3500 has a driver's side air bag but only because someone busted the column and replaced it with whatever they could find, the airbag isn't hooked up, but it would fool someone that just happened to peek into the window, ya know?

As far as the rear O2's, every OBS dually I've seen with a Vortec engine has 'em, I'm definitely not arguing with you about them because by no means have I seen them all. Just going off what I have seen.

Richard

Krewz i will solve your dilemma, ship it to me and i will glady take it off your hands for ya... problem solved

gm offered an option in the 3/4 ton and 1 ton trucks which was airbags. they have nothing to do with the o2 sensors, how ever, when you got the airbag option, it had the rear o2 sensors as well. i have seen trucks without bags and still have the rear o2 sensors, but every 1 ton i have worked on so far has'nt. i have a 2000 with a vortec 7.4 that doesnt have them. i just did a 98 dually the other day that i put a billet steering wheel on, and the customer couldnt because it had an airbag from the factory!! had to remove the bag and clock spring to make it work. the customer was going to just remove the srs bulb after he got it back. who knows what all gm does!! its aways better to look at these damn things than to go off the vin # theres no telling what the factory threw in

Finally got mine finished today, took of both cats, put in some straight pipe and done deal. Already had the pipe so didn't cost me nothing but time. No ses light and doesn't sound really any different, just a hair louder. While I was at it, I raised up the crosspipe from the drivers side manifold to where the cat was, as it used to hang down too far. So killed to birds with one stone.

Sorry low, its staying up here, unless you gotta a crapload of cash.

Thanks for the advice guys, save me some cash.

brianbgboy I believe you if you say you've pulled the bag and clockspring out of one; I guess I've just seen the opposite, always - no airbags, and they do have rear o2's. Hell I've got three here right now that fit that scrip. A '96 and two '98's, though one '98 is a 5.7, the other two trucks 7.4's. I have had some lengthy debates with a few people about airbags when they call me for parts, only to later have to show them that the horn cover on their truck is just that, a horn cover that is styled to look like an air bag. They never seem to listen when I tell 'em "go read the steering wheel, does it say 'supplemental inflatable restraint' anywhere on the horn button?"

Of course one of the '98's fails that quick check because of the column swap I mentioned earlier.

Richard