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Thread: Fine tuning idle using a datalog.

  1. #1

    Default Fine tuning idle using a datalog.

    A few years back I built and dynoed a marine 565 Whipple engine for our boat. The dyno performance was flawless at all areas including tip-in off of idle under load. The large 4.0 Whipple has a very large throttle body blade which adds some sensitivity to this area.

    Based on a limited memory, I had updated the EFI software & ECU firmware to V2 prior to any real on water testing and then experienced a complete fail to come off idle in gear. I was finally able to throw a bunch of fuel in this area, which helped some but I’m not so sure that was the answer.

    After reading a bunch I found where the newer version EFI software had added a new feature that killed my previous Acceleration Enrichment settings. This was the AE vs TPS RoC Blanking and AE vs MAP RoC Blanking located in the Fuel Control which nullified any off idle enrichment I had. Dropped those down from the default to 2.0 and 3.0 respectively and all seemed much better.

    So now, few year later (we obviously don’t use the boat as much as we'd like) I'd like to go through and smooth the idle and off idle areas.

    When looking back at my datalogs the idle seemed to like the fuel at ~11.0 @ 67 kPa out of gear and ~13.4 @ 74 kPa in gear ~800 RPM. This is assuming the number in the datalog is the actual fuel the engine is seeing. (?)

    My question. Beings the ECU uses a 3x3 block to adjust fuel, how can I smooth the table while not having the tip-in effect the 800 range? It transitions fine now, but I feel there are some holes that could be filled and smoothed in the idle area. Note, these datalogs are with Closed Loop Parameters enabled at 1100 RPM, Learn is enabled 0 RPM.

    Two pics of idle. One in-gear, one out-of-gear. One pic of fuel without learn and smooth. One pic with Learn and smooth.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  2. #2
    Join Date
    Dec 2009
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    Connecticut
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    Read 4th & 5th paragraphs: http://forums.holley.com/showthread....2523#post62523 (Actually, read the entire post.)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, 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 M/T Street Comp tires.

  3. #3

    Default

    Will do. Thanks.

  4. #4

    Default

    Are those pictures of your Base Fuel Table? If so, that's a very weird Base Fuel Table. It looks more like a chart of random numbers than a Base Fuel Table.

  5. #5

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    Trust me. I know. LOL. My graphs are generally very, very smooth (Both FAST and Holley). That's why it needs work. The switch to the RoC Blanking was very frustrating and resulted in a lot of grief. Seems the change was not communicated well or I was just not observant. A testament to the ECU as it actually performs well other than the occasional burp at idle. Never misses a beat when running hard. I'll get it there.

  6. #6

    Default

    If it was me I'd start by getting rid of the obvious dumb numbers. Find a good value and work from there. If it idles great with 10 lb/hr at 50 kPa and 800 RPM, then make that your starting point. Everything to the left and below should have smaller numbers. Right now you have larger fuel numbers at lower engine speeds than at higher speeds, which is obviously wrong. Either start from a known point and fix it, or scrap it and start over with a fresh Base Fuel Table.

  7. #7
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    25,508

    Default

    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, 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 M/T Street Comp tires.

  8. #8

    Default

    I don't use datalogs for fine idle tuning. I use the Strip Chart and tune it live, even via Team Viewer remotely. Scale the RPM & timing into a very narrow range.

    Tip-in off idle should not be tuned by band-aiding the Base Fuel Table. For AE I usually try 4.0-4.5 for TPS RoC Blanking, and I zero out the MAP AE table (bottom left) effectively making the bottom three tables useless. One thing you may find is the top right table (AE Correction vs TPS) may have to be quite a bit different than usual with the first number several hundreds, and tapering off fast. This is due to the large throttle blade.

    For idle tuning the most important thing is to get the throttle blade set right. Out of gear you want the IAC to be 0% and the timing to be within range. Once that's done you can further tune idle fueling & spark. I turn off Idle Spark control and try to stabilize IPW via the Strip Chart. Keep in mind more timing means less air & vice versa. I find too many people run too much timing at idle and not enough air.

    If you look at the Base Fuel Table in VE mode you'll see the idle area travels in a football area top left to bottom right. You want the cells that it travels through to have a similar VE number.

  9. #9

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    Quote Originally Posted by Danny Cabral View Post
    Danny, I assume the example pics in this link are for the 950? I haven't seen any fuel tables where the number goes down with RPM.

  10. #10

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    Thanks Allan. I agree with all. Are you referring to setting the the zero/zero point on the AE vs MAP Rate of Change table? I don't believe that it can be changed from anything other than zero on the latest V2 version. This is how I discovered the change in the EFI software. Am I missing something? Thanks Again

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