Results 1 to 7 of 7

Thread: No spark has me stumped.

  1. #1
    Join Date
    Oct 2018
    Location
    Portland, Oregon
    Posts
    17

    Default No spark has me stumped.

    The car car has a 5.4L Mercedes V8 with twin-spark "dumb" coil packs - one pack per cylinder, each pack has two internal coils, one for each of the two spark plugs per cylinder. I have a pair of the Holley coil modules (554-123). The System ICF has the Ignition Type set to Custom, with appropriate values for the Cam and Crank sensors.

    Yesterday was the first fire-up of this engine on the Holley. After a bunch of troubleshooting for a no-spark condition, we got it to fire and idle by setting the Ignition Output to "DIS Coil on Plug" (it had been set to "DIS Coil on Plug (Active Low)". After making that change, it fired right up and idled in open loop for a good 10 minutes, with no signs of spark problems. It started right up two more times after that.

    Everything up to this point was done on V5 build 30, so I decided to update the software and firmware to the latest (V5 build 110). Now that I have updated the firmware, I am back to the same problem we had yesterday: no spark. I have not changed any physical wiring on the car, just the software and firmware.

    All sensors and DBW are working correctly. I get a clean RPM signal while cranking, and the TPS Autoset was successful. The coils are getting proper voltage, they just aren't firing.

    At this point I'm stumped, because I know it should run, I have video proof that it ran yesterday! I already tried unplugging the ECU for 30 minutes and updated the firmware AGAIN, but still no spark. Any suggestions will be greatly appreciated!
    - Joe Since 1970
    Follow me on StumptownBenz.com

  2. #2
    Join Date
    Oct 2018
    Location
    Portland, Oregon
    Posts
    17

    Default

    I captured a system log while cranking; here's a zoomed-in view. Am I correct to assume that the EST Spout would go high if it was trying to spark? It looks like it isn't sparking at all; EST Spout is 0 for the whole graph.

    After taking a closer look at this post: https://forums.holley.com/showthread...m-Sensor-Setup, it appears that my problem may be the fact that the cam sync signal is going low (Digital Falling) only 4 teeth before the missing teeth are detected. As this is a non-adjustable factory cam sensor, I'm not sure what to do. I'm also still perplexed as to why it ran fine for 10-15 minutes, but now won't start. What could I have changed?
    Click image for larger version. 

Name:	system-log.jpg 
Views:	18 
Size:	71.8 KB 
ID:	8708
    - Joe Since 1970
    Follow me on StumptownBenz.com

  3. #3
    Join Date
    Oct 2018
    Location
    Portland, Oregon
    Posts
    17

    Default

    Can someone look at this system log and provide some feedback? Two things stand out to me, but I would like confirmation as I'm a newbie at this.

    1) The EST Spout is flat the whole time. Does this mean the ECU is not even trying to spark? Knowing this will help me narrow down the possible problems.
    2) The cam sync pulse is apparently too close to the missing teeth. My ignition settings don't have the "Ignition Reference Angle" that I keep reading about, but I do have the number of teeth BTDC. Do I need to back that up by 320° or so?

    I have logged a ticket with Holley, but I'm still waiting on a response.
    - Joe Since 1970
    Follow me on StumptownBenz.com

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,934

    Default

    Quote Originally Posted by JoeJErnst View Post
    1) The EST Spout is flat the whole time. Does this mean the ECU is not even trying to spark? Knowing this will help me narrow down the possible problems.
    Holley Tech: I’ve never seen a System Log with the EST Spout active, but it’s the EST Spout output for a Ford TFI/GM HEI.

    2) The cam sync pulse is apparently too close to the missing teeth. My ignition settings don't have the "Ignition Reference Angle" that I keep reading about, but I do have the number of teeth BTDC. Do I need to back that up by 320° or so?
    The ECU needs an Ignition Reference Angle, so it can control the synchronized timing.
    The TDC Tooth Number (amount of teeth after missing teeth) is the Ignition Reference Angle.
    It gets confusing because for a 60-2 crank trigger, the EFI software uses the term "TDC Tooth Number" to describe the Ignition
    Reference Angle. Which is fine, since the amount of teeth (after the missing teeth) is more of a definitive method to identify it.
    http://www.masterenginetuner.com/top...all-fails.html (Crank Reference Angle Importance)

    On a 60-2 trigger wheel, each tooth equates to 6 degrees. 60 x 6° = 360°.
    The Ignition Reference Angle needs to be at least 10° higher than the maximum amount of timing used.
    12 teeth is 72° of Ignition Reference Angle, which allows you up to 62° of timing advance (in the Base Timing Table).
    11 teeth is 66° of Ignition Reference Angle, which allows you up to 56° of timing advance (in the Base Timing Table).
    10 teeth is 60° of Ignition Reference Angle, which allows you up to 50° of timing advance (in the Base Timing Table).
    9 teeth is 54° of Ignition Reference Angle, which allows you up to 44° of timing advance (in the Base Timing Table).

    On a 36-1 trigger wheel, each tooth equates to 10 degrees. 36 x 10° = 360°.
    The Ignition Reference Angle needs to be at least 10° higher than the maximum amount of timing used.
    7 teeth is 70° of Ignition Reference Angle, which allows you up to 60° of timing advance (in the Base Timing Table).
    6 teeth is 60° of Ignition Reference Angle, which allows you up to 50° of timing advance (in the Base Timing Table).
    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.

  5. #5
    Join Date
    Oct 2018
    Location
    Portland, Oregon
    Posts
    17

    Default

    I have read that the cam sync pulse needs to be at least 8 teeth before the missing teeth are seen by the ECU. In my case, it appears that the falling side of the pulse is only 4 teeth before the end of the missing teeth (two "seen" and then two "missing" teeth). Will this condition cause no spark at all, or will it cause spark to happen at the wrong time?

    Maybe I should change the "TDC Tooth Number" from 11 to 64 (because (360 + 24)/6 = 64). I arrived at this figuring I want the cam pulse to happen on the revolution prior to TDC (hence the 360°), but I also need an extra 4 teeth of rotation (the 24) and each tooth is 6°.
    - Joe Since 1970
    Follow me on StumptownBenz.com

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,934

    Default

    Quote Originally Posted by JoeJErnst View Post
    Will this condition cause no spark at all, or will it cause spark to happen at the wrong time?
    I'm not sure. Perform this ignition timing cylinder sequence verification/synchronization:
    Originally Posted by Danny Cabral
    Ignition Timing Cylinder Sequence Verification
    Ensure the Firing Order is entered correctly in Ignition Parameters (System ICF).
    Before the initial start, disconnect the fuel injector harness and verify
    at least, the first four cylinders in the firing order using a timing light.
    If your cylinders are firing in 90° intervals BUT in the wrong sequence,
    the coil harness is connected wrong (at the ECU or at the coil packs).
    Hopefully you have a fully degreed balancer or at least markings every 90°:
    1st cylinder, in firing order, should fire at 0° (or 15° - add whatever your cranking timing is)
    2nd cylinder, in firing order, should fire at 270° (or 285° - cranking timing added)
    3rd cylinder, in firing order, should fire at 180° (or 195° - cranking timing added)
    4th cylinder, in firing order, should fire at 90° (or 105° - cranking timing added)
    5th cylinder, in firing order, should fire at 0° (or 15° - cranking timing added)
    6th cylinder, in firing order, should fire at 270° (or 285° - cranking timing added)
    7th cylinder, in firing order, should fire at 180° (or 195° - cranking timing added)
    8th cylinder, in firing order, should fire at 90° (or 105° - cranking timing added)
    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.

  7. #7
    Join Date
    Oct 2018
    Location
    Portland, Oregon
    Posts
    17

    Default

    Closing the loop on this. The car runs now, but I still don't know exactly what the problem was. My best guess is that the calibration file was somehow corrupted in the ECU. Eventually I switched back & forth between batch-fire & sequential fueling strategy and it started working. Now the car will run with either of them selected. I've stared it a dozen times or so, and driven it for about an hour with no problems. Now I can get to tuning!
    - Joe Since 1970
    Follow me on StumptownBenz.com

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us