Has anyone had a SES 0420 (Rear O2 Cat inificiency) with the Vishnu exhaust?

 

I have a Vishnu signature dump-back exhaust with hi-flow cat ... no SES so far.

l8r)

 

did you run leaded race gas if you did your cat will be taost. It happened to 2 friend her that ran race gas with the cat on the car.

 

I get that code with my vishnu exhaust. once about every 2 months. if i use the test pipe i get it right away of course.

 

Thanks for your help. I have been getting it with the Signature Turbo Back with high flow cat.

I have not run leaded race gas.

SF

 

Mine threw the PO420 before I used race gas....(my wife was learning to drive stick!!!and it threw)
I think some evos are a bit more sensitive than others with that high flow cat installed, just clear the code with a battery disconnect and it should not return for a while....
There is a fix for this if that fails that a few of the members are using, call me tomorrow at the shop if you want details on "How To"

 

This is a fix that's been going around. I hated the code on the vdubs motronic, losing the post cat readings isn’t good as it allows the ECU to adapt for pre-cat sensor aging.

I'm about to take the plunge on a dump back but the p0420 gives me cold feet.

 

I ended up getting that code on my way to streets of willow raceway for an EOC event. I have never run any race gas in the car and the code just popped up. I cleared it about four times at the event, but it just keeps coming back. I disconnected the battery and the code came back in less than two days. I do have the high flow cat and it really sucks having to look at that bright orange light on my instrument cluster.

 

I received it when I tried to use a baffle at the end of the tip to suppress exhaust noise. As soon as I put on the vortex cone silencer, the SES light came on. I had the code read as the P0420, and I cleared it out thinking it was an anomoly. Drove for 2 miles and it came on again. Checked everything I could think of and figured it was from the cam and flash tune. Then I realized that I slapped on that silencer immediately after having the car tuned.

I took it off and reset the ecu. No SES light.

Seems as though the slight backpressure caused by the silencer was enough to lower the cat-con efficiency of the Signature turbo-back.

If you're running a silencer, remove it. Then check to see if the midpipe and muffler section is perfectly lined up. The silencer I used was not very restrictive (imagine a cone that is completely perforated) and yet it was enough to throw off the cat efficiency.

 

I had the same problem with my signature exhaust. I ended up chasing it for a few months. Would go away for awhile and then come back. I finally ended up believing that it was the O2 sensor itself. I replaced it with a new one ($90 ) and it went away for good (4+ months). I believe that I actually may have damaged it in the install. It was a pretty expensive lesson, but now it is fixed.

I hope this helps.

HiVolt