11 votes
Accepted

What's the meaning of a "lean" vs "rich" air fuel mixture

I do not know the etymology of these words or the history of their use in the context of air-fuel ratios, although their dictionary definitions (lean [adj.], rich, too bad I don't have an OED ...
Jason C's user avatar
  • 4,890
7 votes

What's the meaning of a "lean" vs "rich" air fuel mixture

A lean air/fuel mixture is when there is more air than required to burn the fuel. A rich mixture is when there is too little air for the given quantity of fuel. The ideal mixture, where there is ...
Steve Oakes's user avatar
  • 1,096
3 votes

Black water from exhaust, cylinder misfire and rought idle

Solved, it was a fuel injector that sprays extra gasoline. Cylender 1 was the almost the only one that misfires although others does every now and then. The situation becomes worse when I add ...
Aus's user avatar
  • 276
2 votes

Spark Plug Deposits

Depending on the mileage on these plugs, I'd suggest there's absolutely nothing wrong with the way your engine is running. These plugs look to be in great shape. The small amount of deposits on the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
1 vote

Subaru Forester - petrol coming out unlit in bursts out exhaust. Ideas on what could cause it?

Super simple, but I reset the error codes with a little bluetooth OBDII scanner and the engine has come right!
Jesse Reza Khorasanee's user avatar
1 vote

Subaru Forester - petrol coming out unlit in bursts out exhaust. Ideas on what could cause it?

Possibly a faulty spark plug, ignition lead to the plug, or a faulty ignition coil. If you are not getting a spark at one of the plugs, you will get unburnt fuel coming out of the exhaust and it would ...
HandyHowie's user avatar
  • 25.2k
1 vote
Accepted

How can I diagnose if my engine is running lean or rich?

If your car is running rich you should have a strong smell of gasoline from your car. Have you considered using an air/fuel ratio gauge? Personally, I prefer to see the exact number. I have the air/...
Travis's user avatar
  • 26
1 vote

Is there a chemical limitation to the mixture an engine can maintain?

You can't go any leaner than injecting no fuel whatsoever. This may sound dumb but actually an engine will continue to spin for a few firing cycles without fuel. Some engines are able to actually ...
Steve Matthews's user avatar
1 vote

What's the meaning of a "lean" vs "rich" air fuel mixture

Ideal air fuel mixture (ratio) is 14.7:1. That is 14.7 parts of air ignites with 1 part of fuel. This will archive the best fuel economy and lowest emissions. This figure is also known as Lambda 1. ...
Adam Cimler's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible