What do spark plugs look like when running lean?

A common symptom of your car running lean is that your spark plugs are clean or turn white. Spark plugs are generally a brown or grey color, which is caused by normal ignition.

What causes too rich fuel mixture?

Fuel Injection and Rich Air Fuel Ratios Faulty components such as dripping fuel injectors, fuel pressure regulators, ECT’s and stuck open thermostats cause this problem. This results in high emissions (HC’s) and black colored exhaust.

Can running too rich cause knock?

Yes overly rich afr’s can also cause knock. it can cause knock. It can also saturate the cylinder walls with gas and prevent proper oiling as well as fuel mixing with the oil.

Can a rich mixture cause pinging?

Detonation occurs when excessive heat and pressure in the combustion chamber causes the air/fuel mixture to ignite on its own. This causes a sharp, sudden rise in cylinder pressure which subjects engine internals—pistons, rings, bearings, gaskets, etc. —to severe overload and creates a pinging or knocking sound.

What air fuel ratio is too rich?

A lean mixture would be one with a ratio greater than 14.7:1 for gasoline. An A/F ratio that contains less air and more fuel than the stoichiometric ratio is called a RICH fuel mixture. A rich mixture would be one with a ratio less than 14.7:1 for gasoline.

What should AFR be under boost?

As load increases, the engine mixture should be richened. Typically, around 13:1 AFR on naturally aspirated engines at high load, and richer still (11-12:1 AFR) on forced induction engines as you enter boost. High RPM, low load should aim for 15:1 AFR for a ‘lean cruise’ to increase MPG.

What is a good AFR at idle?

How does it affect performance?Gasoline AFRMethanol AFRCruise14.7-15.56.4-6.8Idle13.5-15.06.0-6.6Stoich14.76.4WOT11.5-13.35.1-5.

What is the correct air fuel ratio for hard acceleration?