Causes For failing smog test

[Garagebound]

Looking at purchasing a ZHP with ~90k miles. The car fax report shows that it failed to pass CA smog in March and is now for sale by a new owner.
Red flag? Thoughts?

Thanks

[derbo]

Find out the numbers first and see what is causing the failure. It could fail just for something small like a Check engine light for a vacuum leak.

[ELCID86]

Not sure how the smog test works. Is it just sensors in the tailpipe or also OBD2 codes?


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"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - anonymous

[holyc0w]

From http://www.dmv.org/ca-california/smog-check.php

Smog inspections consist of a visual test and a machine test.

During the visual test, the inspector will check for any blue or black smoke emitting from the tailpipe. As long as there is no blue or black exhaust, the vehicle passes this part of the exam.

During the machine test, the inspector will attach vehicle components to a smog check machine and run the test for certain codes. If the vehicle components pass each code, the vehicle passes this part of the exam.

Though I'm reading that similar that for 2000+ year vehicles the exhaust sample test was eliminated, so it could be a check engine light.


I found this part to be slightly funny

If your vehicle is 6 years old or less, you do NOT have to have your vehicle smog checked every 2 years. Instead, you'll pay an annual $20 smog abatement fee for your first 6 years of registration. After these first 6 years, you will be subject to the regular smog check program.

[GotZHP]

They no longer use the sniffer in the tail pipe. They read the computer for check engine light codes and the readiness sensors. They also do a visual under the hood and under the car for obvious things like aftermarket parts. Anything post cats is ok to replace as it doesn't actually effect the emissions.

My car passed smog somehow and I wonder how. I think the PO new a guy type deal. MY CCV failed and was causing oil to go back into the engine via the massive vacuum leak that was caused by failed intake manifold gaskets. Also, I threw 2 codes shortly after purchasing the car. p2237 & p2240, which are related to O2 sensors.

So if the PO didn't know somebody, then my car goes to show that SMOG testing vehicles can be inconsistent and that different cars can fail for different reasons.

If I were you, I'd pay the ~$150 dollars to have a full visual & diagnostic inspection on the car by an Indy BMW Shop. There could be other maintenance items that need to be completed as well, like cooling system, belts, pulleys, battery, etc.

Engine codes are beneficial to know, but a simple tool costing under $30 dollars can clear the codes (temporarily).

I am also in Socal and bought my car down here. Mine was smogged shortly before purchase luckily. You can always ask the current owner to Smog the vehicle, then you will buy it.

As for causes, Cats would be the expensive one, and the exhaust design has the Cats taking a lot of heat. After market parts that are not CARB compliant can cause failure. Failed O2 sensors, check engine codes, disabled readiness sensors cna all cause failure.

90k on the clock you say, any maintenance records?

[das boots]

90K on the clock would be way too low for the cats to fail. Do as Got ZHP says...get a pre-purchase inspection from a BMW cert. mechanic. And open up Pandora's box of worms.

[Garagebound]

I appreciate the insight and suggestions.

Cheers,