Hey guys,

As some may know, my cat is not the right one for my truck. I am going to have to buy a new cat in about a year and a half, so I can pass smog here in CA. For now though, I have a question.

Will the service light come on if I cut the cat out and just run a straight pipe? It comes on now I think because of the wrong cat. It's to small. I am hoping to solve the light problem by putting a straight pipe on it for now. What are some of the cons' of taking the cat off and not replacing it? For now that is.

If not, no big deal, just means I will have to use my new code reader to turn the dumb thing off every so often! LOL

 

No, you won't get a Service Engine Soon or Check Engine Light if you put a straight pipe on a 7.3L diesel.

Now, a 6.4L or a 6.7L you will have an issue, but on the 7.3L and 6.0L you'll be OK.

 

Not sure that it matters but I think she has a v10

 

Oops, forgot to put it is a 1999 F350 V10 SD. My bad!

 

I think it is against Federal/State law to remove the cat for street use....

 

Trucks sold originally in california had to have an 02 sensor after the cat to monitor the efficiency for obd2 compliance; trucks sold everywhere else (250s and 350s that is) do not have an after cat sensor, so they would not know whether the cat is acting normal or not. Get underneath and see if you have a sensor, that'll answer your question. If you don't have a sensor, you can go ahead and do it, if you have one, stop by autozone and have them check the code(s) thrown. You can turn off the 2nd sensor in a tune, or you can run an eliminator that tricks the computer (nothing more than a resistor wired in to an extension for the o2 sensor). I don't know where you can buy those anymore or where you can get the components to make one though...

If you ask me, life was better before catalytic converters... One less expensive pos part to rob you of power, mpg, and to get clogged up...

 

the p.o. was kind enough to remove the cat from my 03 f250 and I wish that they wouldn't have. It is just loud and has an obnoxious tone/cackle to it, not like the old v-8's. I don't care what people say, as long as the cat is in working order it will not rob you of any noticeable hp or mpg because the friggin thing was design to run with it.

 

It may have been designed to run with it, but so have all of the newer diesels and their MPG/power robbing emissions controls. On my mustang removing all 6 of them *******s made a big difference at the track (weight savings alone made a difference), on my jeep the power gain is noticeable... I told myself I'll keep the X quiet, and keep finding reasons not to take it off, but if I can't figure out my low mpg woes (how I came upon this thread), I'll be hacking it off soon enough, as it may be plugged... And there's no way I'm paying 800 bucks for a new one.

 

I have a 5.4 and i removed the cat and replaced with strait pipe. on mine, not sure on the V10..but there is no 02 sensor after the cat so no issues.

 

It's your vehicle and do as you please. I am telling you that cat's on these newer trucks aren't as restrictive as you lead them on to be. If we were back in 1980 then I'd agree 100% to get rid of them. That muffler that's three feet long will restrict more than the cats do. The cats on the diesels are not the same as what's on this guys' truck. Now that we mention the diesel exhausts, they are not even close except for the fact that they make the vehicle meet emissions and make it quieter.

 

oh, btw.....the emissions standards for 3/4 and 1 ton trucks are completely different than your mustang and jeep.

 

Can anyone tell me how to post a question??? thank you first time using

 

I have recenetly bought a 350 and am hauling rvs with it,,, put the bigger exhaust ,,,and chip in it and air intake ,, but I am still only getting 13 mpg empty and loaded average,,, what else can I do to get the better mileage otherwise i will be parking the truck !!!thank you

 

Yah, this is a CA truck in CA. I know it is illegal to not have a cat, but we were only going to run no cat till we had to smog it again in a year and a half. We were just thinking that the cat on it now is to small and restricting, so if we just ran straight pipe, it wouldn't be restricting it. I just don't want the to small of a cat to do damage to my trucks engine because it gets to hot or something.

We don't have the 2+ grand to buy a new cat right now.

I do think it has the sensor behind the cat too. I will have to double check though.

My tranny guy turned the light off when he cleared the codes. It stayed off till I ran down the freeway. Then it came back on. I got home and turned it back off with my new code reader. That is when I thought of putting the straight pipe on. Even if it (straight pipe) doesn't keep the light off, would it be better to go with no cat, or keep a to small of cat on it?


As far as posting a new question. Go to the sub forum you want to ask in, for example, SuperDuty & Heavy Duty. Then inside that forum click on "New Thread". That will open up a spot for you to type your question in! Hope that helped?

 

I couldn't see 2k for a cat so got a Magnaflow universal hi-flow cat for IIRC 169 bucks free shipping. Can't remember from who but check around.