Power FC IDLE timing wont change
IDLE timing wont change
so i cant get my AFR's to lean out for my 850 primary's. I have removed all emissions on my build. The secondary's are set on setting 5 to 60% and a -.40 lag front and -.30 lag on rear rotor. i cant get a lean idle i have once but it would just start spuddering and die. the timing at 900 rpms is 4 degrease leading even tho i have that area on my base map set to 8 so i am stumped any suggestions. note i have my n values start at 800 and it goes up 400 rpm each cell.
here's a basic breakdown of how the PFC controls idle. It is possible to run complete manual control over idle ignition timing but you will lose ISC function.
Advanced Idle Troubleshooting - Idle IG control
Based on your settings in the etc. --> function select menu, the PFC controls idle with the following logic:
1. O2 feedback and Idle IG Control ON (default): PFC controls idle fuel based on factory O2 sensor signal, PFC uses closed loop idle control. Neither fuel nor timing are directly adjustable by the user.
2. O2 feedback OFF, Idle IG control ON: User can control fuel, closed loop fuel is disabled completely, PFC varies idle timing in an effort to reach target idle speeds. Turning off O2 feedback is usually necessary on cars without an airpump.
3. O2 feedback OFF, Idle IG control OFF: Ignition timing is fixed at
-5 L, -20 T for no load idle, same as the FC and FD service manual spec and same as the yellow and red timing marks on the FC crank pulley
4 L, -6 T for electrical load idle. electrical load is triggered by either engaging the fans (fan output) or by the PFC receiving a signal from the electrical load detection computer (ELD input)
I don't know the fixed A/C ignition timing values off the top of my head.
The ignition timing is completely static for the three idle conditions (no load, fans or electrical load applied, A/C load). The PFC manual specifically states that turning off Idle IG control was intended for checking ignition timing with a timing light. On an FD that's not normally necessary, although it is on an FC because the crank angle sensor is installed like a distributor.
4. O2 feedback OFF, Idle IG control OFF, idle speeds set to 0. This is what many refer to as "manual idle control," and can only be enabled with a Datalogit. The user has complete control over idle ignition timing but the ISC valve no longer functions for A/C or E/L idle up or improved cold starting. There are advantages and disadvantages to this configuration, and all I will say is that using this depends on your setup and your personal preferences. PM Chuck Westbrook (cewrx7r1) about tuning notes, I won't go into it much because this thread is all about Commander tuning.
With an ISC installed and no airpump, I personally prefer to have O2 feedback OFF and Idle IG control ON. Now let's discuss steady state (not decelerating or free revving) idle speed control before we get to the very thorny issue of deceleration idle problems.
With Idle IG control ON, the PFC calculates ignition timing in this basic way:
base idle ignition timing (a separate value for no load, electrical load, or A/C) + closed loop correction factor
The closed loop correction factor is somehow calculated by measuring how far the current speed differs from its target, or the "error" term for those of you with any knowledge of closed loop jargon. With idle IG control on, the PFC will vary the ignition timing within some range of authority in order to stabilize engine vacuum and get closer to the target idle speed. The PFC will also add more idle air through the ISC valve when electrical or A/C load are applied, even if they have the exact same target idle speeds.
The PFC will advance ignition timing to raise the idle speed or retard ignition timing to lower the idle speed. While it is not possible to directly set idle ignition timing without full manual idle control, a little fiddling with the idle settings will accomplish the same goal. As counterintuitive as it may seem, my current idle speeds are:
1000rpm no load
950 rpm E/L
950 rpm A/C (no A/C is installed on my 2nd gen but I have tuned A/C idle before)
Yet with my throttlebody adjustments, I actually idle at around 900rpm with no load or electrical load applied. Basically I adjusted the idle through the TB down (in order to prevent idle sticking on decel) then effectively raised the base idle speed through indirectly manipulating the PFC's ignition timing logic. Note that this is on an engine with large intake and exhaust ports that pulls very little vacuum for a non-bridge engine. The work-arounds and manipulations I have done are probably not necessary on most people's setups. You need to remember that The PFC and the throttlebody adjustment all work together to control idle speed under various driving conditions.
Based on your settings in the etc. --> function select menu, the PFC controls idle with the following logic:
1. O2 feedback and Idle IG Control ON (default): PFC controls idle fuel based on factory O2 sensor signal, PFC uses closed loop idle control. Neither fuel nor timing are directly adjustable by the user.
2. O2 feedback OFF, Idle IG control ON: User can control fuel, closed loop fuel is disabled completely, PFC varies idle timing in an effort to reach target idle speeds. Turning off O2 feedback is usually necessary on cars without an airpump.
3. O2 feedback OFF, Idle IG control OFF: Ignition timing is fixed at
-5 L, -20 T for no load idle, same as the FC and FD service manual spec and same as the yellow and red timing marks on the FC crank pulley
4 L, -6 T for electrical load idle. electrical load is triggered by either engaging the fans (fan output) or by the PFC receiving a signal from the electrical load detection computer (ELD input)
I don't know the fixed A/C ignition timing values off the top of my head.
The ignition timing is completely static for the three idle conditions (no load, fans or electrical load applied, A/C load). The PFC manual specifically states that turning off Idle IG control was intended for checking ignition timing with a timing light. On an FD that's not normally necessary, although it is on an FC because the crank angle sensor is installed like a distributor.
4. O2 feedback OFF, Idle IG control OFF, idle speeds set to 0. This is what many refer to as "manual idle control," and can only be enabled with a Datalogit. The user has complete control over idle ignition timing but the ISC valve no longer functions for A/C or E/L idle up or improved cold starting. There are advantages and disadvantages to this configuration, and all I will say is that using this depends on your setup and your personal preferences. PM Chuck Westbrook (cewrx7r1) about tuning notes, I won't go into it much because this thread is all about Commander tuning.
With an ISC installed and no airpump, I personally prefer to have O2 feedback OFF and Idle IG control ON. Now let's discuss steady state (not decelerating or free revving) idle speed control before we get to the very thorny issue of deceleration idle problems.
With Idle IG control ON, the PFC calculates ignition timing in this basic way:
base idle ignition timing (a separate value for no load, electrical load, or A/C) + closed loop correction factor
The closed loop correction factor is somehow calculated by measuring how far the current speed differs from its target, or the "error" term for those of you with any knowledge of closed loop jargon. With idle IG control on, the PFC will vary the ignition timing within some range of authority in order to stabilize engine vacuum and get closer to the target idle speed. The PFC will also add more idle air through the ISC valve when electrical or A/C load are applied, even if they have the exact same target idle speeds.
The PFC will advance ignition timing to raise the idle speed or retard ignition timing to lower the idle speed. While it is not possible to directly set idle ignition timing without full manual idle control, a little fiddling with the idle settings will accomplish the same goal. As counterintuitive as it may seem, my current idle speeds are:
1000rpm no load
950 rpm E/L
950 rpm A/C (no A/C is installed on my 2nd gen but I have tuned A/C idle before)
Yet with my throttlebody adjustments, I actually idle at around 900rpm with no load or electrical load applied. Basically I adjusted the idle through the TB down (in order to prevent idle sticking on decel) then effectively raised the base idle speed through indirectly manipulating the PFC's ignition timing logic. Note that this is on an engine with large intake and exhaust ports that pulls very little vacuum for a non-bridge engine. The work-arounds and manipulations I have done are probably not necessary on most people's setups. You need to remember that The PFC and the throttlebody adjustment all work together to control idle speed under various driving conditions.
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