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Forum > Failed Smog Test > Question

1993 Toyota Pickup failed smog check due to incorrect ignition timing.

My car just failed smog today. Passed in every category except 15mph HC. Max in California is 95 and it scored 106. At 25mph it scored the max of 60. It was recently tuned up and driven over an hour before the test. The tester suggested changing the timing as it was 5 BTDC, using a carbon cleaner - then retesting. I'm leaving the country for an extended period in a few months and need to get this resolved so the car is registered. Any other quick fixes? Have been driving 87 octane - would higher be better, a different type of oil? Thanks.
Answer:

The ignition timing is correct at 5 degrees BTDC, we don't recommend changing that. High HC is usually due to a fault somewhere within the ignition system. You want to start by ensuring the spark plugs are all in good condition and worn evenly. if no porblems are found there, you should have your Toyota's fuel feedback system diagnosed. The feedback system controls how much fuel the engine receives at any given moment. Both, too much and not enough, fuel can cause high HC.

posted by SmogTips Support

 

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