Tech Notes:
 TECH - FAQ's  

 
Fuel Mixtures - Too Rich, Too Lean
 

  
 
 
 Fuel Mixtures - Too Rich, Too Lean
 
Follow closely, maybe even read the following points more than once.
 
  • Running "lean" can be too much air.
  • Running "rich" can be not enough air.
  • Running "lean" can be not enough fuel.
  • Running "rich" can be too much fuel.
As we all know, an overly "rich" or "lean" condition in the motor can be costly. Especially in a new or rebuilt engine. The point made above simply states that, if your engine is running too "rich", it doesn't necessarily mean that it's getting too much fuel. These conditions can change any time you add a performance part to your engine.

"Rich" fuel conditions cannot only contribute to poor fuel economy, but it can lead to a poorly operating engine. Extreme "rich" conditions can cause significant engine damage, especially to a brand new or re-built engine. "Lean" fuel conditions can cause just as much of the same problems of a "rich" condition. In some cases, a "lean" motor may cause piston and cylinder head damage. This is why proper tuning is so important.

Factory EFI (22RE) motors do have the ability to be tuned for an overly "rich" or "lean" condition. LC Engineering stocks a Pro Tuning Kit (Part #24-111) that includes a Cyberdyne Mixture Meter and a Pro Tuning Module that will give you the ability to adjust the fuel curve of the engine. This will assist in tuning the factory EFI computer to suit any higher performance parts that have been added to the motor.

Carbureted engines have the ability to control "rich" or "lean" conditions by installing different sized jets in the carburetor to adjust for those conditions. Again, proper tuning of an engine will contribute to longer life, better performance and possibly better fuel economy to an already proven Toyota engine. If you have any questions, please feel free to contact our Technical Department at 928-505-2501.
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