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Thread: 4DI V2 Acceleration Compensation and...

  1. #1

    Default 4DI V2 Acceleration Compensation and...

    I'm just getting around to firing up a 900 cfm 4DI system that has been in the box since new. It is version 2.1 and I'm running it with DOSBox DOS emulator, and have a few questions.
    1) Will powering up with the injectors disconnected hurt anything?
    2) Can the function of the acceleration enrichment be explained?
    3) It appears that acceleration compensation (graph) is throttle angle controlled in version 2.1 and MAP controlled in version 3.38.
    (I loaded it on my machine for reference, but don't have the updated firmware.)
    3.38 is confusing, to the right of the graph is says throttle, but in the summary in the top left of the same screen, it says MAP?
    4) It appears that the acceleration compensation was changed from a 16x16 table to an 8x8 in 3.38, was this to free up space for other functions?
    5) Is it OK to run the system with two disconnected (open) injector channels, I.E. leaving the back (2) barrels disconnected for testing purposes?
    I have a 2 barrel 454 TBI on a test stand that I would like to test it on.
    Best regards.

  2. #2
    Join Date
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    Quote Originally Posted by SuperMdad View Post
    1) Will powering up with the injectors disconnected hurt anything?
    No.

    2) Can the function of the acceleration enrichment be explained?
    Acceleration Enrichment is additional fuel injected when the engine is accelerated.
    The accelerator pump & power valve on a carburetor performs the same function.
    http://forums.holley.com/showthread....9444#post29444 (EFI AE in Carburetion Terms)

    3) It appears that acceleration compensation (graph) is throttle angle controlled in version 2.1 and MAP controlled in version 3.38.
    (I loaded it on my machine for reference, but don't have the updated firmware.)
    3.38 is confusing, to the right of the graph is says throttle, but in the summary in the top left of the same screen, it says MAP?
    Some diagrams were most likely reused from the old 2.1 version user manual.

    4) It appears that the acceleration compensation was changed from a 16x16 table to an 8x8 in 3.38, was this to free up space for other functions?
    It was decided the larger table was unnecessary, and was more work for the end user.

    5) Is it OK to run the system with two disconnected (open) injector channels, I.E. leaving the back (2) barrels disconnected for testing purposes?
    Yes.

    http://documents.holley.com/techlibrary_r10022.pdf (Holley Pro-Jection 4D & 4Di Manual)
    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/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  3. #3

    Default

    Danny, first, thanks for the valuable information. However, regarding question #3, you referenced the user manual. I was actually referring to the software Graphs. 2.21 shows RPM, throttle, and fuel quantity labels on the graph, and in the summary for the current graph pointer position at the top left of the graph screen. In version 3.38 it shows RPM, throttle, and fuel quantity on the graph same as 2.1, but the summary for the current point in the upper left of the screen has RPM, MAP and fuel. I expected the graph and pointer summary to match. Is it actually supposed to be throttle (I'm thinking throttle angle) in the summary for both version 2.1 and 3.38?

    Also, the manual I have only references fuel being removed for a specified O2 sensor voltage, whereas the 3.38 manual references being able to remove & add fuel based on O2 sensor voltage settings. Is this true for 2.1 as well, and just not mentioned in the manual? Best regards.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,702

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    I don't have answers to those questions. You can try contacting Holley Tech Service (Link), however, most of the tech staff won't be knowledgeable with such an old antiquated (DOS based) EFI system.
    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/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

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