Anybody know smog? Car failed yesterday. Failed 15mph, but passed 25mph. High NO and HC, CO was on the high side as well, but still within limits. From google, sounds like cat, any thoughts?
Smog help?
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I'm bumping this up... Based on everything I've read I believe I have 2 likely culprits. Plugs, wires, dist cap, rotor, injectors, hoses, etc... Have all been recently replaced. Timing was tuned recently as well. The only things I'm unsure of are the cat and the o2... When I bought the car neither of those items were on it and I bought both used. When I drove the car home, it pulled through the rev range very nicely, but I noticed that wasn't quite happening driving it around Saturday before smog, but it wasn't terrible. Well, I decided to disconnect the o2 and see how the car responded... Well, it idles higher, but pulls considerably harder. So I'm pretty sure it's the o2. Any other thoughts? -
Post a picture of your results."I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj
85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
88 M3 - LACHSSILBER/SCHWARZE
89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER
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Well Before any smog test. I normally Do a fresh oil change,Run highest Fuel i can get 92 octane or higher. Make sure plugs are all gaped correctly,and normally run a new O2 sensor.
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All of that done with the exception of the o2... I always run 91, but that's the best I can get locally. Everything else had less than 50 miles on them prior to the test, including cap, rotor, wires, Tstat, tbelt, water pump, etc... Literally spent the last 3 months doing maintenance on the car. The only used parts were the complete exhaust and o2. Going to install a new o2 tomorrow and get retested. I really don't think the cat is bad after driving it with the o2 unplugged yesterday. There are no tell tale signs (rotten egg, back pressure, rattling).Comment
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Oxygen sensors are maintenance items so I would get a new one if the one you have is of unknown condition. They dont have to be terribly expensive. The cat fails low speed but passes high speed so its probably not getting hot enough. Did you run it hard right before the test? Are we talking about a used stock cat or aftermarket?"I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj
85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
88 M3 - LACHSSILBER/SCHWARZE
89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER
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I wouldn't say I ran it hard, but I did drive it around for a good 30 minutes. I will really romp on it this time around. The complete stock exhaust was used, but I was told it was used by a shop to get cars to pass smog. I trust the seller, but I would rather not say who that was.Comment
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