Running Without Cat

[wierdo124]

My cat went out, i couldn't afford to fix it at the time, and so i put a steel pipe through it. Runs great now. Except my mileage is down about 3mpg. To me, sounds like the O2 sensors are getting confused and telling the PCM to run more rich, using more gas. My question is, would that be plausible? I'm getting about 15mpg off a 4.3L. There's only one cat. Now, most cats are upwards of $200. But summit has the MAgnaflow 99006HM (http://www.summitracing.com/parts/MPE-99006HM/) for $80. Why is this so cheap?

[Nytemare]

My cat went out, i couldn't afford to fix it at the time, and so i put a steel pipe through it. Runs great now. Except my mileage is down about 3mpg. To me, sounds like the O2 sensors are getting confused and telling the PCM to run more rich, using more gas. My question is, would that be plausible? I'm getting about 15mpg off a 4.3L. There's only one cat. Now, most cats are upwards of $200. But summit has the MAgnaflow 99006HM (http://www.summitracing.com/parts/MPE-99006HM/) for $80. Why is this so cheap?

Its a universal one.

If you don't have a Check Engine Light on your O2's are likely functioning properly.

[wierdo124]

Forgot to say, yeah she's throwing an SES

[Wingnut]

Have your rear 02's tuned out (and get a nifty new good tune in the process).

 

You'll get the mileage back.

[Nytemare]

Have your rear 02's tuned out (and get a nifty new good tune in the process).

 

You'll get the mileage back.

+1......Million

[wierdo124]

Have your rear 02's tuned out (and get a nifty new good tune in the process).

 

You'll get the mileage back.

Define 'tuned out'

[Nytemare]

Have your rear 02's tuned out (and get a nifty new good tune in the process).

 

You'll get the mileage back.

Define 'tuned out'

 

Actually get its operating parameters removed from the Operating system on your trucks ECM...just like it has never existed. This requires a custom tune by someone like BlackBear performance or Wheatley.

[wierdo124]

How much would that cost?

[Nytemare]

How much would that cost?

http://www.blackbearperformance.com/

 

Give Justin and Jenna a call, or look Jenna up on here (Jennabear) for additional info.

[wierdo124]

I'm not gonna spend that much.

[chakis24]

what state are you from? no cat or 02 sensors = emissions fail (unless you can figure out a trick way to fool the computer they hook up to it- and the visual inspect). but you may be lucky and not have to worry about this, unlike me

[Nytemare]

I'm not gonna spend that much.

You wont spend 200ish bucks to get a custom tune and get rid of your O2 issue....????

 

You will save fuel and gain power with the tune...probably the most bang for your buck you will ever do with any 96+ GMT

 

I paid for my tune with fuel savings in about a year and a half....and the truck is way more fun to drive.

[Z'06]

what state are you from? no cat or 02 sensors = emissions fail (unless you can figure out a trick way to fool the computer they hook up to it- and the visual inspect). but you may be lucky and not have to worry about this, unlike me

 

Even if there is a visual inspection, as long as there is no sniffer test, you can get away with gutted (or piped through) cats if you tune out your rear O2 sensors (this is the "trick way to fool the computer" you mention in your post).

[wierdo124]

I'm from Minnesota, rural. There's no emissions test. As for why i don't want to spend the money for the tune, the truck has 200k miles on it, i'm not about to drop 200 bucks to tune a truck this old. I'm not going to upgrade it, i'm going to drive it into the ground. Knowing my luck, the minute i spend that money is the minute it dies. If i don't spend the money, by my luck, it'll never die

[Nytemare]

I'm from Minnesota, rural. There's no emissions test. As for why i don't want to spend the money for the tune, the truck has 200k miles on it, i'm not about to drop 200 bucks to tune a truck this old. I'm not going to upgrade it, i'm going to drive it into the ground. Knowing my luck, the minute i spend that money is the minute it dies. If i don't spend the money, by my luck, it'll never die

Grab the $80 universal Cat than man.

That may or may not fix your issue...

 

Another thing to try is to pull the rear sensor out and install a spacer between it and the pipe. A couple spark plug indexing rings should do it. It may pull the sensor just far enough out of the exhaust stream to get it to register the correct readings.