Pontiac 2.8 V6 Failed Emission Test (Hydrocarbons)

Any ideas? My car failed MA state emissions test due to excessive hydrocarbons. Car is a 1988 Pontiac Fiero Formula v6 (2.8L GM FI).

HC GPM = 2.54 (limit was 2.00) CO GPM = 13.98 (limit was 30.00) NOx GPM = 2.04 (limit was 3.00) CO2 GPM = 188.57

I have replaced O2 sensor, adjusted timing (w/ ECM in diagnostic mode as instructed), oil change w/in last 2 months (Mobil One 5w30, low mileage), cleaned distributor cap & plugs (bosch platinums w/ under

5,000 miles). Plugs were lightly coated in black residue.

Mechanic performed emissions test without letting car warm up (does that matter?)

Am not a mechanic but can follow guidance (and really appreciate any advice you can offer on what I should do to pass :-)

Thanks, Bob Levy snipped-for-privacy@rcn.com

Reply to
Bob
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Yes, it needs to be up to temp. Also a 16 year old converter may be getting tired.

Reply to
Jim

Hi, Also air fiflter? Tony

Reply to
Tony Hwang

Reply to
news

if the engine is not warm it will not burn hydrocarbons and they will read high. if the engine runs too warm it will burn all the hydrocarbons but will produce nitrogen oxides. the catalytic converter will not work until the engine is warm (the converter works as an after burner to burn off hydrocarbons in the exhaust)

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Reply to
William R. Watt

Bob:

He's a friggin' idiot. The car should be as hot as possible when conducting the test. The State of MA has large posters that they provide to inspection stations telling the mechanics and the consumers that the car must be fully warmed (driven for at least

20 minutes) before testing.

Go out and drive it hard, bring it in and have it inspected at some place that will do it when you get there. You'll pass.

Reply to
Bob

That could get rather expensive considering that emissions tests are often required every year or every two years...

Use what is recommended by the manufacturer for the ambient temperature in your local. If the oil has been changed at the intervals it's suppose to be with a quality product, such nonsense becomes unnecessary.

Better yet, make certain it is up to operating temperature.

Reply to
Neil Nelson

Lemme guess... they don't do emissions testing where you live (?)

Reply to
-Bob-

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