Closed/Open Loop and PE Tuning
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Teching In
Joined: Mar 2011
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Closed/Open Loop and PE Tuning I've been reading a bit preparing to start logging/tuning once I get HPT. I believe my PCM understanding is ok to this point, but have a question.
When warmed up you are either in closed loop or PE and the OL table is not referenced (maybe in PE if richer). Can we use this OL table without completely disabling CL operation?
My understanding (if PCM chooses richer parameter) is to purposely make PE AFR leaner so PCM references OL during PE. Is this a tuning technique?
The reason for asking is thinking how to tune smoother transitions at part throttle instead of just stoich or PE AFR.
When warmed up you are either in closed loop or PE and the OL table is not referenced (maybe in PE if richer). Can we use this OL table without completely disabling CL operation?
My understanding (if PCM chooses richer parameter) is to purposely make PE AFR leaner so PCM references OL during PE. Is this a tuning technique?
The reason for asking is thinking how to tune smoother transitions at part throttle instead of just stoich or PE AFR.
So by doing this your hoping to accomplish what? Do u have any mods done to the car if so what are they?
Once in closed loop u will stay in cl until criteria is meet to exit it like going wot. Hen it uses pe to get fueling to the desired in the pe table. Why do u want it to go to OL when doing part throttle? There is no need for it in a NA car
Once in closed loop u will stay in cl until criteria is meet to exit it like going wot. Hen it uses pe to get fueling to the desired in the pe table. Why do u want it to go to OL when doing part throttle? There is no need for it in a NA car
Thread Starter
Teching In
Joined: Mar 2011
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My question was more to further my PCM logic understanding. I don't have HPT yet (except for the demo), but once I do, I'll be tuning a stock car to start... kinda playing around for knowledge.
Currently I understand that PCM will be CL until conditions are met (mainly TPS) for PE which is a 2D table with rpm. So if OL table is referenced during PE for the richer setpoint... my thought was to enable PE earlier, but with a lean-ish AFR so the PCM will reference the OL table. If this is possible you could tune smoother AFR transitions instead of 2 choices per rpm. Anyway, just curious.
Currently I understand that PCM will be CL until conditions are met (mainly TPS) for PE which is a 2D table with rpm. So if OL table is referenced during PE for the richer setpoint... my thought was to enable PE earlier, but with a lean-ish AFR so the PCM will reference the OL table. If this is possible you could tune smoother AFR transitions instead of 2 choices per rpm. Anyway, just curious.
TECH Senior Member
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From: So.Cal.
While in OL, when PE enables, the PCM selects the richest of the active fuel tables (the OLFA and PE tables are both active) on a cell-by-cell basis.
Once CL is reached, the PCM retains CL and will not revert to OL when PE enables (going from CL to PE does not go to OL, but rather stays in a pseudo CL mode, and the only active fuel table is the PE table, the OLFA table is not active).
Once CL is reached, the PCM retains CL and will not revert to OL when PE enables (going from CL to PE does not go to OL, but rather stays in a pseudo CL mode, and the only active fuel table is the PE table, the OLFA table is not active).
