Join the community and post your question. Use our Ask-A-Tech for free now! ASE experts standing by.

Forum > Failed Smog Test > Question

My 1992 Pontiac Grand Am failed the emission test with measured HC of 122 at 15 MPH and 100 at 25 mph.

My 1992 Pontiac Grand Am failed the emission test with measured HC of 122 at 15 MPH and 100 at 25 mph. All other measurements were near the average limits. What would cause the spike in HC, is there a simple and inexpensive correction that I could make to lower the results. What would be the best or most likely correction to make? Thanks for any advise you can provide.
Answer:

Hydrocarbon (HC) is basically raw fuel, otherwise known as gasoline. The main reasons vehicles fail for high HC is defective spark or ignition system. Out of the 3 systems your engine relies on to produce combustion (air intake, fuel delivery, and spark ignition control), the ignition system has components which require replacement most often. Sparkplugs and spark wires are constantly exposed to high temperatures and high voltages. You must ensure your engine's ignition system is working properly by inspecting all the sparkplugs and sparkwires. If any of the plugs look worn out or have excessive carbon build-up replace them immediately. You may use any brand of product designed to work in your vehicle. The distributor cap should also be inspected for cracks or excessive carbon deposits. If it appears that the cap may be faulty, you will need to replace it. More then likely you will see an instant performance increase once these corrections are made, as well as a decrease in HC. This is an excerpt from a SmogSmart VIR report, and is not intended to replace a hands-on diagnosis. posted by SmogTips Support

Related questions and answers you might find useful:

How Do I Get a Smog Check Waiver? by Margaret

Do I Need a Smog Check This Year? by Joy

Mini Cooper DMV Registration Due in 5 Day Won't Pass Smog by anne

2001 Jeep Grand Cherokee Laredo with K&N Air Filter by David

1995 BMW M3 Gross Polluter High HC & NO @ 15MPH by Jared

View SmogTips.com in: Desktop / Mobile