Hey guys, hope everyone had a merry christmas! I recently installed a highflow cat with ubend delete from magnaflow on my monte. After 50 miles the damn engine check light went on (anyone notice the pic of the engine doesnt look **** like one?). I wrote to magnaflow and checked posts, but couldn't find much help. I already tried taking the battery off to reset the comp, didnt work. I read suggestions about visiting autozone for help via code reader, what do I say when I go there? I also read I should take this as an opportunity to get a pcm since they add HP and turn the pesky light off due to the cat and 02 sensor. Will this pass inspection if I have a new pcm in there? I also read maybe to wait it out and keep putting miles on and hope it fixes itself. I also am wondering if a ported polished and de-screened MAF could be furthering this problem or causing it with the new cat (the new maf has been in for hundreds of miles and the light never came on). So what shall I do--wait it out? put back in my old MAF? get in the zone with AUTOZONE? or pcm (pending u guys telling me if I will pass inspection with a new one)

 

If its running fine just drive it.It ussually takes the pcm a couple hundred miles to recognize/callibrate to the new part.If it dosent go out within the week. Just tell them your check engine light is on, at autozone.As far as inspection goes, as long as the part is "50 STATE LEGAL" or "C.A.R.B. exempt.There should'nt be a problem.

 

I and a handfull of others have had this problem as well when upgrading the down pipe/high flow cat. You can get an O2 simulator from www.3800performance.com that will get rid of your problem. Or DHP software to kill the code all together.

http://www.3800performance.com/Merch...oduct_Count=17



You will fail inspection with the SE light on and especially with the code being related to the O2.

 

Hey, got my code scanned for my Cat problem, guy said engine was running too lean. I know this means too much oxygen, but could this code be misread by the 02 sensor because of the higherflow downpipe and cat I have?

 

yah thats the same problem on mine...so i gotta get this fixed before next june for the the emmissions test up here what do you need to do to get rid of the code???

 

Yes, it is the cause of the fault. Get the O2 simulator and your problems will go away. What was the code?

Below was a write up on my installation and problems...

https://montecarloforum.com/m_14656/mpage_1/key_/tm.htm

 

why do you need to put an o2 simulator in there when the o2 is still there???

this is what i can't figure out, my o2 sensor is still there so i shouldn't be getting a code come up...but i still am

 

Wiz,

When you install a DP or a high flow CAT you are getting way better air flow than stock, your O2 sensor has high/low tolerances and if they are exceeded or not met you will get an O2 sensor failure code. The simulator will simply tell the computer that it is reading in tolerance measurments. DHP software will allow you to kill the code all together from what I have been told.

 

I am about to order the randowm technologydownpipe and high flow so should i go ahead and get the o2 simulator now or wait to see if the check engine light comes on.

 

probably further ahead to order it @ the same time, because from what it sounds like everyone has the same thing happen