I have a 1993 S10 Chevy Pickup. It failed the smog test. It shows high HC at 15 miles per hour. The HC ppm were fine at 25 miles per hour. What would cause me to fail at the lower speed? Answer:
Vehicle's typically fail the 15mph test portion more often due to the fact the load applied to your vehicle during the low speed 15 mph test is twice as high as the 25mph test. 15mph/50% Load. 25mph/25% Load. The system is designed to simulate city and highway driving conditions.
posted by SmogTips Support
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