Help! Running rich after N1 catback installation?

[masticatingcow]

Hey NICO,

I finally installed my Apexi N1 Dual Catback and yes, it's obnoxiously deep and loud (good thing) but after running about three blocks on it, my CEL came on and every now and then, I blow out some black smoke (bad thing). I am assuming I'm running rich; has anyone else had this problem? My buddy has a slightly younger KA and has had no problems whatsoever.

My setup: Injen intake -> KA24DE -> Hotshot header -> 2 1/4 or 2 1/2 inch collector -> stock cat -> Apexi N1 Dual Catback

His setup: eBay intake -> KA24DE -> Stock exhaust mani -> stock collector -> stock cat -> Apexi N1 Dual Catback

For the record, I got mine first. LOL. Anyway, any help would be appreciated! I've also lost some low end (no real surprise) but can I make some of it back up with a tuned AF radio?

Thanks in advance.

[Dano]

find out wat code your throwing... then post up. could be as simple as an o2 problem. just putting an exhaust on doesnt make a car run richer...

-Dan

[sensibleS13driver]

It doesnt seem like anything behid the cat should make a difference, i know a cat-delete test-pipe doesnt either but the root of the problem most likell is not your catback but something more internal, just a coincidence that it happened with the new exhaust.

BTW I want that exhaust!!!!!!111

[masticatingcow]

32. Faulty EGR system. Looks to be a long day. LOL.

[DAEDALUS]

Very likely not causing the rich condition, unless the valve was stuck open or something, and exhaust was unintentionally being allowed to enter combustion chambers. Doesn't ever happen that way, I don't think.

[masticatingcow]

I figured the EGR issue was just a peripheral problem. I've had EGR codes thrown before, so no big surprise.

In hindsight, I'm probably assuming too much about my friend's KA. Perhaps my A/F better than I think, and he's just running lean? I wouldn't be surprised, the way he beats on that poor engine.

So a stupid n00b question for those which catbacks, do you get popping and backfiring every now and then? It this behavior normal? I assume that it is not, but I have no prior experience to judge that by.

As with many of my other mods, I'll just do the best I can and when I don't know what else to do, I'll just take it in and have it looked at.

[gaehrings13]

Check the o2 sensor make sure the wire isn't grounding out or broken. Disconnect the 02 also and see what happens too.

[chilnviln]

having the same problems. hks catback installed a week ago and getting intermittent CEL and smoke. also, my intake, mani and cat are stock so there shouldnt be an issue with disconnected lines or sensors and i never had this problem before the exhaust was installed.

[masticatingcow]

having the same problems. hks catback installed a week ago and getting intermittent CEL and smoke. also, my intake, mani and cat are stock so there shouldnt be an issue with disconnected lines or sensors and i never had this problem before the exhaust was installed.

Same symptom here. My EGR is/was dirty as hell. I still need to get in there with some carb cleaner and REALLY clean it. I was talking to a friend at a "party" this weekend, which was really a bunch of car guys having a late night BBQ, who suggested that perhaps the drop in backpressure and subsequent accelerated exhaust gases only made an existing problem more prevalent. I think there is some validity to this; my EGR has thrown codes a few times since I bought the car a couple years ago, but I've passed smog twice with no problems, and thus not cleaned the EGR.

[chilnviln]

ive only had the car four months now and havent had issues with it, besides the hatch leaking and major interior and undercarriage washing. the car doesnt feel to happy revving past 6k. unlike my old civic, which was great past 8000 rpm, once it hits aboot 6000 it starts getting sluggish and doesnt want to go any farther. dont know if it could be a bad egr system or a tired motor (just passing 180k)

[bcar240]

Ya, I would guess that the catback is not the direct cause, maybe a contributing factor. I got popping/backfiring like you mention on my old KA, especially during fast drops from high rpm. That motor I believe was kinda tired though. Did you notice any of that before?

ive only had the car four months now and havent had issues with it, besides the hatch leaking and major interior and undercarriage washing. the car doesnt feel to happy revving past 6k. unlike my old civic, which was great past 8000 rpm, once it hits aboot 6000 it starts getting sluggish and doesnt want to go any farther. dont know if it could be a bad egr system or a tired motor (just passing 180k)

The stock KA engine in 240s doesn't really have any significant power gains over 6000 rpm, as you have found out. Most people I know up-shift around 5500-6000. Some go a little farther to get higher in the powerband for the next gear. The KA is a torquey little guy, but not very high revving. Unless a turbo is involved, I don't see much good from being close to redline. p.s. the hatch leaking is very common, http://www.240sx.org/faq/index.html and go to "water leak," thats the most common problem.