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Spark plug gap and emisson
1990 Toyota Camry

Spark plug gap and emisson

(1990 Toyota Camry)
I think I made a mistake by setting the gap at 0.030 before going to the SMOG station.

I gather from the internet that wider gap is better for low rpm fuel economy and better emission for HC.

The spec is 0.043, someone told me.

Is 0.043 the best to pass smog in terms of HC? Can I gap to 0.052 for the best HC result?
1 answer & 0 comments
Popular Answer
on October 01, 2010
the spec is .043", for both the V6, and the Inline 4. The theory behind enlarging gaps, is that a larger gap creates a larger spark, thus more effecient ignition. The problem is, your ignition system was designed for the .043" spark plug gap, not larger. Enlarging the gap puts a greater strain on your ignition system components, and it may not be strong enough to jump a larger gap. The result would be less efficient combustion, or a cylinder(s) that won't fire at all. Pull your plugs, and set them at .043". Check the distributor cap, rotor, wires, and your filters. Make sure the car is totally warmed up before the smog test. Good luck.
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General Diagnosis
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on October 01, 2010
the spec is .043", for both the V6, and the Inline 4. The theory behind enlarging gaps, is that a larger gap creates a larger spark, thus more effecient ignition. The problem is, your ignition system was designed for the .043" spark plug gap, not larger. Enlarging the gap puts a greater strain on your ignition system components, and it may not be strong enough to jump a larger gap. The result would be less efficient combustion, or a cylinder(s) that won't fire at all. Pull your plugs, and set them at .043". Check the distributor cap, rotor, wires, and your filters. Make sure the car is totally warmed up before the smog test. Good luck.
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