I recently had a 3" helix Downpipe to a 3" high flow cat to a 5Zigen pro 3" exhaust. After it was installed it felt and sounded great with no engine light for about 50 miles of driving then the Service Engine light came on when I was driving. I was pissed that it came on but didnt feel any loss in power which is good but I still wondered what it was. I took the negative off my battery and left it off for about 10 minutes to reset the ECU. The car was fine for about 50 miles then the engine light came back on. Can anyone give me some adviceas to how can can get it off or what could be causing it.? Do I just need to reset the ECU until my engine learns my parts. Any help would be greatly appreciated. Thanks

 

You probably need to get a o2 simulator. You have a high flow cat which shouldnt set it off but that is the reason, i have a 02 simulator with my test pipe and i never get a check engine light.

 

Where Can I get an 02 simulator and how much do they cost. How do you Install it?

 

he shouldn't need the o2 simulator with the high flow cat should he? we just had this issue with my friends car, but its because it has a test pipe, no cat...

 

Do think If I reset the ecu again maybe it wont go off?

 

My service engine light came on about two weeks ago. I had installed a bored throttle body about two weeks before that and the light randomyl came on. I disconnected the battery and reconnected it and the light went off and has been ever since. I don't know if this will help you at all, but it might be something to try.

 

How long did you leave your battery disconnected before plugging it back in?

 

give her like 10 mins.....and then hook it back up....

 

I did try this before once so far and she went all night with no engine light. I wok this morning and it was like 30 degrees out side. Warmed her up for about 10 minutes then half way to work the engine light popped back on. I drove her almost 60 miles before this happened though. Any explanations?

 

I think the high flow cat doesn't need the O2 simulator, dun u think?

 

I dont no much about High flow cats this is my first one. I just want that engine light to stay off.

 

its probably another p0300 code (random misfire). i had my cel taken off by my mechanic about a month ago and it came on for the first time again a two days ago. i had him scan the code and take it off, today it came on again. no biggie if its the p0300. everyone gets it

 

Maybe, bmaga123: what year is that?

 

You can also do the 02 bung extension fix just get two spark plug anti foulers(18mm I think) and drill one out and then put back in works great with or without a cat and will not give you a check engine light. I know of 5 Evo's in my town who have them and still no check engine light for 6 months. There is a big how too on this site as well

 

Here's the thread
https://www.evolutionm.net/forums/sh...ght=18mm+spark