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Thread: Won't Stay In Closed Loop

  1. #1

    Default Won't Stay In Closed Loop

    I took the car out earlier to try to get some datalogs and allow the Learn feature to make corrections, however, I've noticed that it switches from Closed Loop to Open Loop with no rhyme or reason that I can figure out.
    Here's a screenshot of the datalog at the last frame that it was Closed Loop (part throttle boost):

    And here's the first frame of the datalog where it went to Open Loop:

    One thing I noticed in my tune is that it has a value of 12.0 in the AE vs TPS RoC Blanking, and a value of 6.0 in the AE vs MAP RoC Blanking. Do those have to be zero for it to stay in Closed Loop? Just for clarification, I have only enable Closed Loop & Base Fuel Learn Enabled checked without any of the other options checked. I also have the Coolant Temp Enrichment Table to 100 across the board. Also, I noticed the Air Temp Enrichment is set to 100%, should it be zeroed out?

  2. #2
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    Quote Originally Posted by evobydarwin View Post
    I've noticed that it switches from Closed Loop to Open Loop with no rhyme or reason that I can figure out.
    Closed Loop & Learning isn't active during periods of acceleration enrichment or deceleration (zero TPS, 400 RPM above target idle).
    The engine needs to be at "steady-state" RPM for the Learning to function, at lower RPM.
    The Closed Loop Status has many momentary periods when it's inactive (Open Loop mode).
    This is normal due to the TPS & MAP based acceleration enrichment (transient fueling).
    Also, any "noise" on the TPS or MAP signal wire (false Rate of Change) will deactivate Closed Loop.
    http://documents.holley.com/techlibr...__statuses.pdf (Sensor Diagnostics & Statuses)

    Check the Closed Loop & Learn settings in System Parameters.
    Ensure both are Enabled and "Learn Gain" is 100%.
    Learning won't happen if the idle (RPM) isn't stable.
    Try blocking off the IAC passage to see if it stabilizes the idle. If so, it may be IAC related.
    Ensure the Closed Loop & Learned Compensation Limits haven't reached their percentage limits.
    Initially, if the Closed Loop Advanced Control (1-5) is set too high, it can sometimes inhibit Learning.
    Also, ensure the Learning isn't working because of repeated "RPM Errors", causing repeated ECU "syncing".

    Learning happens at all RPMs, provided the Learn Parameters are programmed as such.
    Is the Coolant Temperature Enrichment % or A/F Ratio Offset still active? These must be at 100% & zero to enter Learn mode.
    You may need to reconfigure these tables if you're running the engine colder than what the base calibration specifies.

    One thing I noticed in my tune is that it has a value of 12.0 in the AE vs TPS RoC Blanking, and a value of 6.0 in the AE vs MAP RoC Blanking. Do those have to be zero for it to stay in Closed Loop?
    No.

    Also, I noticed the Air Temp Enrichment is set to 100%, should it be zeroed out?
    No.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 MT tires.

  3. #3

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    Danny, I've eliminated all the things you posted, except for the electrical interference. Here's the screenshot of when the TPS RoC seemed to throw it out of Closed Loop (frame before the one pictured it was still in Closed Loop):

  4. #4
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    Quote Originally Posted by evobydarwin View Post
    Here's the screen shot of when the TPS RoC seemed to throw it out of Closed Loop...
    Too much AE vs TPS Rate of Change transient fueling can disable Closed Loop & Learn mode. Above 85% TPS (not an RPM condition), the ECU should be locked into Closed Loop (except if a Rev Limiter is activated), UNLESS too much AE vs TPS Rate of Change transient fueling is being added.

    If the AE Fuel ÷ Base Fuel Table is greater than 10%, the ECU will enter Open Loop for .5 seconds (to give it time to finish consuming its AE transient fuel); UNLESS the AFR gets leaner than .5 lean of the Target AFR, then it reverts back to Closed Loop. (Example: 15 ÷ 100 = 15%, so it would enter Open Loop.) This still happens when you're at 100% WOT.

    Once you're at WOT, it should stay Closed Loop above 85% TPS during deceleration transients. If deceleration TPS is greater than 25% per second, it will go Open Loop on deceleration. There's a 3 second timer on this. Once you're 500 RPM above idle speed, it could override the timer.

    http://forums.holley.com/showthread....1379#post61379 (Plotting an AE vs TPS Rate of Change Curve)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 MT tires.

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