Advantages/Disadvantages with Closed loop ECM

Discussion in 'Engine, Fuel and Exhaust' started by Black07Roadking, Jul 29, 2008.

  1. Black07Roadking

    Black07Roadking New Member

    I have a PCIII installed, obviously with the O2 eliminators installed, the ECM is running in OPEN LOOP 100% of the time.

    I also have a SERT (not currently being used... LONG STORY!!!) The SERT allows for CLOSED LOOP operation in the "cruising" range.

    Question for any techies out there...

    What are the advantages/disadvantages with the ECM running in closed loop operation? Is it just EPA/CARB requirements? Fuel economy?

    Any comments/help would be appreciated.
  2. Bud White

    Bud White Well-Known Member Retired Moderators

    Running Open loop will give worse fuel milage and more than likely allow the engine to run a lot richer though the whole RPM range Which can be bad if its to rich ..

    Where is it running the AF Ratio at? though the RPM range

    What i have read is Closed loop works any where from up to 40% or 50% throttle after that its open loop and Richens the mixture up quite a bit..

    So If your running the same air fuel ratio at say 20% with the 02's out of the picture as at 60-70% well your using extra fuel and what isnt burnt goes out the pipes can build up in the crank case.. etc etc