So today my new 1992 325iC failed smog for the second time. In both tests there was no CO% at 25mph and my NO% was also too high on both tests. I've replaced all basic items besides my O2 sensor. Would that be my problem?
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Failed Smog 3rd Time - What's Wrong?
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You are lean. Hot combustion temps.
Run a smoke test on the intake for air leaks. Also measure your fuel pressure while running, possibly low fuel pressure/dirty fuel filter/ dirty injectors.Originally posted by codyep3I hope to Christ you have looks going for you, because you sure as fuck don't have any intelligence.
1988 Blk/Blk e30 factory wide body kit car SOLD
1992 DS/BLK 325 m-tech II apperance pack cabby SOLD!
2002 325xit Sil/blk. SOLD
2012 328i xdrive touring. Wht/blk. SOLD
2009 135 cabby. monacoblue/blk leather SOLD
2007 Z4m coupe. Silver grey/black/ aluminum. 1of50
2010 F650gs twin
2016 M235i cabby. Mineral grey/Red leather
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Just saw the mileage on the car. If the head has never been off, you could have carbon build up in the combustion chamber causing hot spots.
Google high nox and there are quite a few things to check. (Coolant temp sensor/o2 also)Originally posted by codyep3I hope to Christ you have looks going for you, because you sure as fuck don't have any intelligence.
1988 Blk/Blk e30 factory wide body kit car SOLD
1992 DS/BLK 325 m-tech II apperance pack cabby SOLD!
2002 325xit Sil/blk. SOLD
2012 328i xdrive touring. Wht/blk. SOLD
2009 135 cabby. monacoblue/blk leather SOLD
2007 Z4m coupe. Silver grey/black/ aluminum. 1of50
2010 F650gs twin
2016 M235i cabby. Mineral grey/Red leather
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As far as I know the head hasn't been off. Just got the car a few weeks ago. Ive changed the coolant sensor and fuel filter before the second test. I also changed the thermostat because the temp gauge would only reach 1/4, now it reached 1/2 as it should.
Could I do a smoke test through the FPR?1987 325 Turbo
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Those numbers represent an engine running lean. Since the fail is at speed, the rail fuel pressure, injectors, or AFM are all suspects. Intake leaks would cause a failure at idle. You can check the rail pressure by tee'ing in a pressure gauge, zip tying it to a wiper and see what the pressure is at 25mph or higher. It should be about 40psi. Low rail pressure could be weak pump or bad FPR.
If the rail pressure is okay I'd send the injectors to RC Engineering for rebuilding and flow checks. If the car still fails at 25mph I'd swap in a known good AFM. If, at that point the CO level is within bounds and the NOX is out of bounds, new catalytic converters are called for.
It would be a good idea to have a shop run a smoke test just due to the age of the car.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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Would an O2 sensor change anything? I did a stomp test and received a 1222 code, which from my research could be anything from an O2 sensor to running lean/rich. I ordered one on Amazon for $30.
The car itself seems to run perfectly fine other than terrible gas mileage. No hesitation at any time and doesn't stutter if I blip the throttle.1987 325 Turbo
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Originally posted by jlevie View PostThose numbers represent an engine running lean. Since the fail is at speed, the rail fuel pressure, injectors, or AFM are all suspects. Intake leaks would cause a failure at idle. You can check the rail pressure by tee'ing in a pressure gauge, zip tying it to a wiper and see what the pressure is at 25mph or higher. It should be about 40psi. Low rail pressure could be weak pump or bad FPR.
If the rail pressure is okay I'd send the injectors to RC Engineering for rebuilding and flow checks. If the car still fails at 25mph I'd swap in a known good AFM. If, at that point the CO level is within bounds and the NOX is out of bounds, new catalytic converters are called for.
It would be a good idea to have a shop run a smoke test just due to the age of the car.
Have you smoke tested it yet, or checked the fuel rail pressure at speed?
No sense throwing parts at it, your O2 sensor change made no difference except make your wallet lighter.Originally posted by codyep3I hope to Christ you have looks going for you, because you sure as fuck don't have any intelligence.
1988 Blk/Blk e30 factory wide body kit car SOLD
1992 DS/BLK 325 m-tech II apperance pack cabby SOLD!
2002 325xit Sil/blk. SOLD
2012 328i xdrive touring. Wht/blk. SOLD
2009 135 cabby. monacoblue/blk leather SOLD
2007 Z4m coupe. Silver grey/black/ aluminum. 1of50
2010 F650gs twin
2016 M235i cabby. Mineral grey/Red leather
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You can check the condition of the cat with a IR thermometer. Measure the temp of the front and back of the cat after the engine has been running for about 20 min.
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Originally posted by siggy View PostHere is what a virtually new OEM BMW catalytic converter can yield for smog numbers, todays test:
Do I need any new gaskets when changing exhausts?1987 325 Turbo
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