Service Engine Soon Light

[STGGSX]

I have had a problem that i have tried to fix for the past month and i need some help. After installing the Apexi N1 down pipe with not cat, my car would run very rich, and would turn on my serive engine soon light. So i did a boost leak test, no leaks. checked all the fuel areas, no problems there, then i replaced my 2, 02 sensors. and for a week the car has ran great no CEL no rich mixture of gas. On my way home last night the Service Engine soon light came on again. I need your help to tell me how to get this light off and find out why it is coming on, also this Apexi down pipe has been more than a problem since i put it on, do i need to put my cat back on. Thanks

 

[c5chris]

Your problem lies on the 2nd O2 sensor which is there to monitor for the presence of a Catalytic converter. You do not have a cat, it will tell the car that there is a problem with your catalytic converter's efficiency (which in reality, isnt there anymore). There probably is nothing wrong with your car, you just have to find a way to defeat this loop. See if you can add an O2 sim or have the 2nd O2 hang under the car - outside the exhaust system.

 

[DGajre777]

The secondary o2 (the one behind the Cat) is there to tell the ECU if your cat is working correctly. Without the cat the CEL (check engine light) will be on. If you want to get rid of it, put the cat back on, do the mod to bypass the o2 (check tech guide) or buy an o2 simulator from http://www.o2sensorsimulator.com/

Look at http://www.roadraceengineering.com/eclexhaust.htm
They make downpipes and cats that bolt on to the Apexi N1.

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FYI - The richness and the way your car runs has nothing to do with the Check engine light which is triggerd by the second o2. My car runs pig rich on the Apexi N1 and bolt on mods but my Check engine light is not on.

 

[STGGSX]

So if i was to put my old 02 sensor back in the hole in the DP and hang the new 02 out side if the exhast and leave it plugged in this will solve the problem of the Serive engine soon light

 

[skinnykenny84]

mine does the same thing, I just pull the main engine fuse (under hood) reset it and go on. It will come back on usually in about 3 weeks or so and I just do it again.

 

[c5chris]

So if i was to put my old 02 sensor back in the hole in the DP and hang the new 02 out side if the exhast and leave it plugged in this will solve the problem of the Serive engine soon light

O2 sensor #1 - on O2 housing/ downpipe: KEEP IT and make sure it is working

O2 sensor #2 - on catback: Replace with O2 simulator OR hang outside exhaust. Make sure to close the bung if you do the hang method.

This will get rid of CEL (if everything else is fine) after you disconnect the battery/reset the ECU.

 

[STGGSX]

Thanks guys i was getting so mad at this car and i was ready to drive it off a cliff. I will Buy a 02 sim, and try going that route. Also c5cris i think thats your web name we need to meet up next time im down in Cali. Email me thanks.

 

[c5chris]

Happy to help a fellow DSMer.

Drive it off a cliff???!!:: I think everyone on this site had that feeling towards their DSMs at one point.

 

[forGEE63]

Just to make sure that it is your 2nd o2 sensor, take your car to an Autozone, and they will do a obdII scan and let you know what code is being pulled.

 

[skinnykenny84]

Just to make sure that it is your 2nd o2 sensor, take your car to an Autozone, and they will do a obdII scan and let you know what code is being pulled.

everytime Ive dont this I just get a fuel trim code that could mean anything, or the person at autozone hardly knows how to read the damn thing.