Removing cats on a 99 2500

[Zack88]

New to the forum, I just bought a 99 2500 crew cab with the 5.7 vortec. Never been a chevy guy but I love this truck so far.

I bought it to pull my rock crawler jeep to go wheeling with and took the first 300 mile round trip last weekend. Only had a couple of issues one was the dismal 7.5mpg part of the trip and the second the catalytic convertor started to rattle like crazy when the internals broke apart I'm assuming.

The factory exhaust is all in good shape and I don't want to change it up and make it loud and obnoxious ( the jeep is plenty loud enough ). I've read about the non-foulers in the exhaust is their a guaranteed way to delete both cats without getting a check engine light?

 

[DRAGGIN95]

The only way to make absolutely sure the service engine soon light doesn't come on with removed cats is to have the rear 02's turned off in a custom tune in the ecm. I have used non foulers and premade 02 spacers, sometimes with good luck sometimes not.

 

[kennythewelder]

I just removed the cats on my 97 vortec. I used the spark plug non fouler mod. It worked for a few days, then engine light. So I did my research and found these mini cats. They look like the non fouler, but with a little piece of the honey comb just like what I had removed from my cats. I took off the non foulers, that I made and grinded down a small piece of the honey comb that I removed from my cats and cut it about 1/2 inch thick, so it fit between the 02 sensor and the exhaust pipe, inside the non fouler that I did not drill out. I haven't had no engine light come on since, and I went from 13.5 MPG to 14.5 MPG, and gained more power. Here are some videos on the non fouler mod, and a link to the mini cats as they are called. https://www.youtube.com/watch?v=SLXb4fZx4QA https://www.youtube.com/watch?v=wcDPAfz10Io - http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html

 

[Zack88]

That's a good idea on the mini cat, worth trying at least for sure. I figured it might help me get some milage back after removing them. I just can't stand a check engine light and don't wanna have it on but custom tunes aren't in the budget for a couple months yet.

 

[kennythewelder]

Let me know how it turns out. Mine has been great. Keep in mind that the honey comb is brittle. I used a bench grinder to make mine round, to fit into the non foulers, and cut them 1/2 inch thick with a hack saw, but I had to pull the blade slowly. I trided to push the saw, and the honey comb just crumbled. Also it makes a lot of dust when grinding. Where breathing protection. After the honey comb fits good (just a little loose) and it is cut to lenth (I grinded mine just a little after sawing to make them even ) I just blew them clean with my breath, before installing them into the non foulers. By making the mini cats, or even if you buy a set, it gives the rear o2 sensors what they are looking for. The ECM still thinks that there are still cats on the truck, because in a way, there are.

 

[df2x4]

I just can't stand a check engine light and don't wanna have it on but custom tunes aren't in the budget for a couple months yet.

Custom tunes from Black Bear Performance are only $290, and that's with a spare ECM so you can go back to stock if you ever want to. $50 cheaper if you use your existing ECM. If I were you I'd just remove the cats and deal with the CEL until you can afford the tune, no point in doing all that work for a halfway fix IMO. (Actually that's a lie, if I were you I'd just put functional cats back on it. Not like it's going to be a night and day difference in power and/or MPG. To each their own, though.)

 

[Zack88]

The tunes aren't that bad no but with new tires all around on the truck this weekend, two on the wife's car and 4 on the trailer before our trip in two weeks it's a little out of the budget until the play money gets built back up. I was just hoping to have a fast cheap solution before dragging the jeep again to make sure the truck was as optimal as I can get it.

I had plans of just getting new exhaust done and possibly hi flow cats at the same time originally but my exhaust guy is all booked up until august since he only does it on weekends as a side job.

I'm going to so some more research on the black bear tunes though and talk with them before I make a long term decision on cats or not for now I'm going to try and get them out if I have time.( I still have to finish the roll cage and install the 5 point harness' in my jeep and help my friend redo the tongue on his gooseneck trailer and work full time).

 

[GMRedline]

HP Tuners is a software solution that supports your PCM. It costs $100 to register your PCM with the software. Once the software is registered, you can make unlimited changes to the PCM for free. EF Live is another tuning solution but I don't know how that works or what it costs.

It might not hurt to try to find someone local to disable the CEL from your PCM. I have done it for people I know for the cost of the credits.

 

[kennythewelder]

BUMP-- I have run these mini cats that I built for 1 week now, and I still don't have a check engine light. I wanted to remove my cats for a very long time, and had I known that it was so easy to make my own mini cats, I would have gutted my cats a long time ago. This is one of the best performance up grades I have done to my truck. GRATE performance (power) up grade, and I went from 13.5 MPG to 14.5 MPG. Don't get me wrong, A tune is grate, mine is tuned with a Jet programmer set on max, but I built these mini cats for less than $10.

 

[Zack88]

I forgot to ever get back to this thread, for over a month now I've been running drilled out non-foulers with no cats and still haven't had a check engine light!