ECU open loop mode when cold

[R31Heaven]

When should the ECU come out of open loop in cold start mode or what determins it too? is it a set time or does a sensor have a role in it?

[Jolinator]

coolant temp sensor

[ferni]

whats an open loop?

[Jolinator]

me thinks

when your engine is cold i beleive the fuel that isnt used is burnt rather than passed back to the fuel tank, basicly when your cars cold its using twice the fuel and blowing shit....

[JimX]

me thinks

when your engine is cold i beleive the fuel that isnt used is burnt rather than passed back to the fuel tank, basicly when your cars cold its using twice the fuel and blowing shit....

How did you arrive at that conclusion? By what physical process do you think the fuel is either burnt or sent back to the tank depending on the temperature?

[Jolinator]

me is wrong

found this,

Closed loop means that the ECU looks at inputs such as the front O2 sensor and adjusts the fuel for the ideal stoichiometric ratio for maximum efficiency. The ECU makes a change, looks at the O2 readout, makes a change - looping around.

Open loop means that the ECU will ignore most of the sensors and run off the pre-programmed fixed fuel and timing maps. These are very rich, partially for safety. For emissions reasons, the stock ECU will run in closed loop as often as possible. Over a certain load - calculated by air flow - the ECU will go open loop.

[Busky2k]

I believe it goes from open to closed loop operation once the 02 sensor is heated up and reading properly (may take 30secs to 2 minutes) and also once the engine coolant has reached 40C. (Not exactly sure on the figure)