This is topic smog fail...spark plugs? in forum Tech Talk at Northern California Ford Owners .
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Posted by CustomFastbackCA (Member # 1369) on
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Hey guys,
I just failed my smog check for my 95' M3. I know most people are only familiar with mustangs, but M3 guys don't know much about Nitrous and my car has nitrous. My car passed the 25 MPH test (2800 rpm) and failed the 15 mph (1800) test. I have an NX wet kit. I can't think of anything that would make me fail the test, in terms of my nitrous, except for the colder plugs. Would colder plugs make me fail do to an incomplete combustion process? Any other ideas? It passed the Oxygen sensor test. thanks
David
Posted by SALEENx5 (Member # 1605) on
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What did you fail on? HC (hydrocarbons)? CO (carbon monoxide)? NOX (nitrogen oxide)? Or a combintation of the three?
[ January 08, 2005, 09:15 PM: Message edited by: SALEENx5 ]
Posted by CDT (Member # 5004) on
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what emission did it fail on???
Posted by CustomFastbackCA (Member # 1369) on
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It failed on all three, but barely on CO%. The max for HC was 85 and I measured 181. The max for CO was %.50 and I measured %.51. The max for NO was 695 and I measured 1716. I passed with flying colors on the 25mph test, except for HC was pretty close to failing.
Posted by CustomFastbackCA (Member # 1369) on
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Oh yeah, and the car has 119,000 miles with original cats. I was thinking about changing the plugs, puttin' in some fuel additive, and then heatin' up the cats.
Posted by 95 stang (Member # 3449) on
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does it have an egr?
Posted by CDT (Member # 5004) on
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whens the last time you changed the O2 sensor?
Posted by CustomFastbackCA (Member # 1369) on
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yeah.
Posted by CDT (Member # 5004) on
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the NOX failure is probably your EGR system not working
Posted by CustomFastbackCA (Member # 1369) on
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Ok. Don't know if the 0 sensor has ever been changed.
Do you think I could just clean out the EGR tube or would you think a new unit is in hand?
Posted by CDT (Member # 5004) on
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you have to check the system and see what part is not working, it could be the valve needs to be replaced, or the passages clogged or the vacuum solinoid doesnt work.. O2's should be changed at least every 50k miles
Posted by SALEENx5 (Member # 1605) on
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quote:
Originally posted by CustomFastbackCA:
Do you think I could just clean out the EGR tube or would you think a new unit is in hand?
Your BMW M3 does not use an EGR system.
Posted by 99gt-UJSTLST (Member # 584) on
:
quote:
Originally posted by CustomFastbackCA:
Hey guys,
I just failed my smog check for my 95' M3. I know most people are only familiar with mustangs, but M3 guys don't know much about Nitrous and my car has nitrous. My car passed the 25 MPH test (2800 rpm) and failed the 15 mph (1800) test. I have an NX wet kit. I can't think of anything that would make me fail the test, in terms of my nitrous, except for the colder plugs. Would colder plugs make me fail do to an incomplete combustion process? Any other ideas? It passed the Oxygen sensor test. thanks
David
I would change out the spark plugs, your sprak might be to weak at lower RPM's wich would couse you not not burn the fuel completely,
take it to a shop that has pass or dont pay, its worth a try, Their is a smog shop by my house that does pass or dont pay.
hey hows ellenor comeing out.
[ January 09, 2005, 07:47 PM: Message edited by: 99gt-UJSTLST ]
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