closed loop status bit always "yes". &nb

[TT_Vert]

When WOT youa re open loop right? WHy would the status bit say yes??The fuel trim learn goes to NO when i go WOT but not the closed loop fuel. Im confused.

Thanks
dave

[Chris@HPTuners]

the closed loop fuel status indicates the condition for closed loop fuel enable have been met. It means you O2's and other stuff is "ready" for closed loop.

"Fuel System Status (SAE)" is a good one to log to see whats happening (it's a PID not a status bit).

Chris...

[jimmyblue]

Do you have the "secret decoder ring" for translating
the PID number value to the actual status (closed,
open, various faults)? I haven't been able to turn up
any such, in the Help or using Google. I don't expect
the scanner returns text descriptions.

Also, any time you would care to expound on the
open loop logic (what are all the terms, to "step off"
from closed loop when closed loop has been enabled)
that would fill a bothersome hole in my understanding.

[Chris@HPTuners]

Hi jimmy,

the scanner does return text info for this field and other status bits (as much as we could). We tried to make the status bits and other state PIDs undestandable without having to go find a lookup table to see what a bit did and then try and convert from deimal to binary etc. etc. We wanted it all there and automated - hopefully we achieved that.

trying to find some time for the descriptive info is the challenge. Ideally i'd liek to have flow charts or state diagrams for the PCM decision making on Idle, Spark, Fuel, etc. in the help files. This is my goal, i'll let time be the judge of my success.

Chris...

[rattle]

Fuel system status
(Enumerated PID)

This parameter indicates the fuel systems' current state, which will be one of:

Open loop - has not yet satisfied conditions to go closed loop. Normally this is prior to the oxygen sensor(s) reaching operating temperature.
Closed loop - using oxygen sensor(s) as feedback for fuel control.
Open loop - due to driving conditions (e.g. power enrichment, deceleration enleanment).
Open loop - due to detected system fault.
Closed loop - but fault with at least one oxygen sensor, may be using single oxygen sensor for fuel control.

Fuel systems do not necessarily refer to injector banks. Fuel systems are intended to represent completely different fuel systems that can independently enter and exit closed loop fuel. However, banks of injectors on a V-engine are generally not independent and do share the same closed-loop enablement criteria.