General exhaust discussion & questions
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By brandoff88
#349309 i bought I cheapo 4-2-1 header (2 piece) before I got this car and decided to use it, but I noticed when I swapped headers it ran real rich, got to poking around and found that the 02 bung is only seeing gases at the 4th cylinder runner...it has another 02 bung fight before the collector, my question is do you think it would run properly if I capped the upper bung and put the sensor in the one before the collector, or would I have issues..it just runs real rich and smells like a 350 haha
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By brandoff88
#349311 got to doing some research, it seems the crx community do this with the one piece 4-1 dc header with collector bung, and they use 1 wire (non heated) 02 sensors, some say it trips cel for 02, but seeing as I am running a heated 02 sensor that shouldn't be an issue, I just want to make sure its not going to lean out and blow my motor up :thumbdown:
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By teal_dx
#349323 I say give it a try. It's only going to involve lengthening 4 wires and changing the bung plug from one bung to the other. Bung plug :lol:

Or if your o2 sensor is old, you could try replacing it in the upper current location with a new o2 sensor. Your o2 sensor is what tells your ecu if you're running rich/lean, so maybe it is starting to go bad. O2 sensors can read pretty far off before they're bad enough to throw a Check Engine Light.
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By brandoff88
#349339 haha thanks teal little late though, it was a brand new sensor when I put the motor in, ( less than 2500 miles now) couldn't get the old one out of the other manifold, and since I made my own custom engine harness, I didn't have to do any modification, just pull the loom off about 6 inches, and re wrap what I undid, fit with some extra slack to spare haha, I did however notice that my o2 sensor was blacker than night (obviously since it smelt like a carbed 350 at start up) and gave it a gentle wipe with a towel...im just worried that it might have already damaged the sensor but so far no check engine lights and it seems to have leaned out enough, not smelling too rich anymore, but I did reset my ecu so after a few hundred miles the verdict should be in. I think all in all it took me about 25 min to swap bungs and unwrap and rewrap it all...so even if it causes more harm than good I know the switch back will be fairly simple...although I will say using anti seize on the 02 sensor was a smart call haha. and bung plug....sometimes I wonder why things get named the way they do haha..
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By brandoff88
#349795 400 miles later running good no rich smell, mpgs are up and it feels smoother to drive, definitely a wiser choice than buying a new header :thumb: