no muffler = service engine soon?

**via sin dios** · 05-30-2007, 10:45 AM

can cutting off a muffler make the Service Engine Soon light come on
?

**sunsetorangess** · 05-30-2007, 10:47 AM

Nope
If your throwing codes have them read and then post if this is for reference than you should be good
J

BadBlueBird* · 05-30-2007, 10:57 AM

still got cats?

**z28punk** · 05-30-2007, 11:18 AM

there are no sensors by the muffler. the last ones are right behind the cats

**via sin dios** · 05-30-2007, 11:44 AM

i keep hearing that a change of back pressure might cause that to happen.

not only that some things happened that might explain this.

I cut of the muffler and a few days later the light came on. I reset the cpu and no problems for a month. then i put the muffler back on. still no light and everythings ok. I cut the muffler off for the second time and a wek later the light is on......so i reset the cpu and hopefully it wont go back on. the scanner at autozone said its a emissions problem so...........

**2001NBMZ28** · 05-30-2007, 12:57 PM

When I run my cutout open (just before the muffler) it's never thrown a code. The actual code the car is throwing will tell you what's going on.

**jmhvenom** · 05-30-2007, 01:43 PM

Loss of back pressure could throw the A/F ratio, but I dont see removed the muffler changing this enough if you still have full piping.

**02z28ls1** · 05-31-2007, 05:32 AM

Decreasing backpressure could lean out the A/F ratio enough to throw that code (it has been known to happen with header installs for example). Computer might be able to compensate and quit throwing codes. Need to know what code we are talking about to give a better answer.

**Eric @ W.A.R.** · 05-31-2007, 12:44 PM

If you can post the code we can help you find the root cause. Right now all anyone can do is speculate. Best of luck

**mrr23** · 05-31-2007, 06:01 PM

Originally Posted by via sin dios

can cutting off a muffler make the Service Engine Soon light come on
?

no.

**SeVeReDiStOrTiOn** · 06-01-2007, 06:37 PM

Originally Posted by via sin dios

i keep hearing that a change of back pressure might cause that to happen.

not only that some things happened that might explain this.

I cut of the muffler and a few days later the light came on. I reset the cpu and no problems for a month. then i put the muffler back on. still no light and everythings ok. I cut the muffler off for the second time and a wek later the light is on......so i reset the cpu and hopefully it wont go back on. the scanner at autozone said its a emissions problem so...........

Well there you go..what was the code