Closed Loop / Open Loop ?

[VB's03WHTGT]

At what coolant temperture does the computer go into closed loop operation and start reading the O2's?

 

[WhiteDevil]

Its after a certain amount of time from when you start the car i believe.

 

[Rootus]

There are a couple factors. Coolant temp is one of them, in addition to time. I don't have my TwEECer software loaded anymore, so I can't say exactly, but it's pretty low, like 135* or something.

 

[WhiteDevil]

Yeah i dont have mine in front of me either. But it usually takes only a few minutes to reach closed loop on my data logs when driving around.

 

[HISSIN50]

The puter should go into CL once the O2's light off. This can take 30-120 seconds normally (a nice feature of HEGOS).
Then the fuel is trimmed via the sensory input that Rootus mentioned.
On a fox, one sees full CL, per the ECT, at ~178*F. Not sure on an SN.

This is from articles, books and info I have read about the EEC function, so it might not quite be the same as what guys who stream, tune, etc see.

 

[WhiteDevil]

Hmm thats interesting. Well i know that it only takes a short time for my car to start going into open loop. But on the stock comp when you are first at idle or when you are decelerating(things that bring you out of closed loop) you will not get numbers from the OL_stabalized_fuel until you reach 160 degrees. You will get them from the other table whos name escapes me right now.

 

[mo_dingo]

yeah, the ECT doesn't affect the time when it goes into CL. Since our O2's are heated through 12V, they don't need the heat of the exhaust to get hot enough....

I don't know the time, But I believe 120 seconds sounds right. That is about the same time as when the smog pump turns off.
Scott