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Thread: Cannot Add Timing

  1. #1

    Default Cannot Add Timing

    Hey Gang. Finished an engine rebuild over the winter and converted to Holley EFI at the same time. Below are details of my setup:
    460 BBC
    Holley MPFI intake
    Holley 1000 cfm throttle body
    Holley 48 lb/hr injectors
    Holley HP ECU
    Small Cap GM HEI distributor

    I started with the mid-level MPFI base calibration, which closely matched the intake duration of my cam. This base map includes 25° of idle timing to get started. I have been attempting to start it for weeks with a high idle and popping through the exhaust (indication of running rich?), until last weekend. I disabled spark control and enabled static timing check. I locked the timing in at 6°, matched it exactly at the damper with a timing light and it idles great. Below are some of my readings after coming up to temperature:
    Idle = 900 RPM
    MAP = 60-63 kPa
    TPS = 0%
    IAC = 5%
    MAT = 135°
    CTS = 180°
    Commanded AFR = 14.0
    Actual AFR = 13-16 (flutter on datalog)
    Timing = 6.0° (on laptop and timing light)
    Timing retards slightly as RPM is increased.
    Set to open loop (until I can figure out timing)
    Ignition Type = GM HEI
    Ignition Reference Angle = 10°
    Inductive Delay = 1.0 usec

    Here's the problem - I drove it around the block, but it's pig sluggish. I can continue to increase static timing one degree at a time and immediately observe slightly improved throttle response. It will not, however take any more than 10° before it starts popping through the exhaust again, and will die if I try pushing it to, say 12°. Any ideas why I'm so far off from the spark table, commanded timing? Thanks, Augie

  2. #2
    Join Date
    Nov 2013
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    Chicago IL
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    1,952

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    Your Ignition Reference Angle is only 10°. It needs to be 50°-60° before TDC. It can't put more timing than your current 10° reference angle.

  3. #3
    Join Date
    Dec 2009
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    Connecticut
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    23,394

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    Quote Originally Posted by Augie View Post
    Inductive Delay = 1.0 usec
    Your ignition timing isn't fully synchronized.
    http://forums.holley.com/showthread....ents-Read-This (Initial Checks & Adjustments - Read Step #4!)

    Quote Originally Posted by S2H View Post
    Your Ignition Reference Angle is only 10°. It needs to be 50°-60° before TDC. It can't put more timing than your current 10° reference angle.
    10° Ignition Reference Angle is correct for GM HEI & Ford TFI. The GM HEI & Ford TFI distributors are installed at 10° Ignition Reference Angle, but they're operating one crank revolution ahead, so they're retarding a lot. On a high RPM race engine, it's best to keep the amount of ignition retard (occurring from such an advanced reference angle) to a minimum, so it's not used on expensive race engines. Of course, timing accuracy is better with a crank trigger.

    FYI: Holley EFI now sells their own Dual Sync Hall-Effect distributors (LINK).
    They're a small cap design, "plug & play" with Holley EFI, and no need for a modified Firing Order.
    The crank & cam sensor signals also provide sequential injection capability (MPFI applications).
    It's "plug & play" (into the 10-pin ignition connector on the EFI Main Harness) and requires a CD
    ignition box (Instructions). The MSD 6201 Digital 6A CDI box & 8253 HVC-2 coil are a great match.
    The MSD CD ignition box is wired as shown in the Holley EFI Wiring Manual:
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual - Figure 11, Page 20)
    https://www.youtube.com/watch?v=AM7r-DauCak (Holley EFI Dual Sync Distributor - YouTube Tech Video)
    A blank cap (LINK) is available, if the user decides to convert to Coil-Near-Plug/DIS later (no CDI box).
    Of course, this component can also be used as a crank and/or cam sync/oil pump drive unit.

    The Custom Ignition Parameters (in System Parameters) for the Holley EFI Dual Sync Distributor:
    Ignition Type ............. ― "Custom"
    Crank Sensor Type ..... ― "1 Pulse/Fire"
    Sensor Type .............. ― "Digital Falling"
    Inductive Delay .......... ― "100.0 usec" ( Synchronization info, adjusted per application.)
    Ignition Reference Angle ― "50°" ( Inherent rotor-phasing of this unit.)
    Cam Sensor Type ........ ― "Single Pulse" ( "Not Used" for TBI, unless CNP ignition.)
    Sensor Type .............. ― "Digital Falling"
    Output Setup Type ..... ― "Points Output" ( CDI box ground trigger.)
    Dwell Time ................. ― "2.0 msec" ( Do not set this to 1.5 msec!)
    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.

  4. #4

    Default

    Thanks for the prompt replies!

    Danny, appreciate the reminder link to finish up the timing sync process. (I've read it numerous times via others' posts as well.) This evening I'll tune the Inductive Relay to a value that stabilizes timing at increased RPM. But do you believe that adjusting this setting alone will allow the engine to run at a more reasonable 25° (versus a max of the 10° I'm at now)?

    Regarding ignition control modules, I'm running a brand new BWD (O'Reilly brand) unit, rather than a Delco as recommended elsewhere on this forum. Could this be part of my problem? Is there any value/risk in trying to adjust the Ignition Reference Angle to other than 10°? This is not a dedicated race vehicle, and I prefer to use the simple, integrated small cap HEI over a more complex (& expensive) Dual Sync Distributor/CD box/crank trigger combination. Thanks again, Augie

  5. #5
    Join Date
    Dec 2009
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    Connecticut
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    Quote Originally Posted by Augie View Post
    ...over a more complex (& expensive) Dual Sync Distributor/CD box/crank trigger combination.
    The Holley Dual Sync Distributor does not use a crank trigger.

    Ensure you don't have any erroneously programmed "Warning Enabled Timing Offset" parameters
    in the "Sensor Scaling/Warnings" (System ICF) or in the custom Inputs (Inputs/Outputs ICF).

    You may have to post your Global File for us to analyze. Global Files & Datalogs must be linked
    to a document hosting website such as Dropbox.com. Someone will analyze it & offer advice.
    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.

  6. #6

    Default

    Thanks Danny. Had time this weekend to tinker & research the forums some more. A number of posts suggested using the Delco module, so I replaced mine and set the Inductive Delay to 245 usec. Double checked my timing with spark control disabled, and all seems to match. I can now command timing from the table, while maintaining a consistent idle and about 8.5 fuel flow. P & D Terms seem happiest at 20 & 40, and timing fluctuates up & down within a couple degrees of the commanded value. It seems to rev cleaner off of idle now, and just waiting for the rain to pass for another test drive. Thanks again, Augie.

  7. #7
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
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    Quote Originally Posted by Augie View Post
    Thanks Danny. A number of posts suggested using the Delco module, so I replaced mine and set the Inductive Delay to 245 usec.
    I can now command timing from the table, while maintaining a consistent idle and about 8.5 fuel flow. Thanks again, Augie.
    You're welcome, and thanks for the update.
    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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