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Thread: Upgraded from round LSx coils to Smart Coils, sputter but no start.

  1. #1

    Default Upgraded from round LSx coils to Smart Coils, sputter but no start.

    The LSx started and ran fine with the LS coils, but once swapped over to the smart coils, the engine sputters & fires almost, then a backfire & dies. It has the Motion Raceworks sub-harness with the thick gauge power/ground harness divorced from the main connector. Verified voltage @ the harness and everything appears normal. Set Dwell @ 4.5 ms at crank. Is there some other setting in the ECU I need to change to get it fire up, or am I missing something here?

  2. #2
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    http://forums.holley.com/showthread....ing-Holley-EFI (Ignition Timing Synchronization)
    CNP/COP/DIS & single coil/distributor ignition synchronization verification & troubleshooting information at the end of post #1.
    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

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    Alright, so I did have one sub-harness backwards. Verified continuity between the sub-harness Metri-Pack connector and Pin A on all the Smart Coil 5-pin connectors. Backfire is gone, but it won't light off; just an occasional cough that sounds like something is lighting off in the exhaust. I left basically everything in place and placed the OE style coils back in service and it fires/idles on the 1st crank without hassle, so timing appears right.

    Is it imperative that the the high current ground (on the 'big wire' sub-harness) is ran independently all the way to the battery, or can it have it's own dedicated ground point to the cylinder head, two independent, dedicated grounds, per bank?

  4. #4
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    Please follow these instructions: https://documents.holley.com/199r11219.pdf (Holley 558-318 CNP Ignition Sub-Harness Instructions)
    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

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    OK, does the ground that goes to the battery need to be independent (so two 10 gauge grounds, ran directly to the remote mounted battery) of the other bank. Or can they both ground to a single wire (4 gauge?) that then runs to the battery?

  6. #6
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    Please be specific as to which ground pin you're referring to. There's more than one ground wire.
    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

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    The high current ground, that goes to Pin D. As far as I can tell, that's the only place that I deviated from the instructions, I have four independent thick gauge grounds, each going to its own dedicated spot on the corresponding head.

    Engine has a 4/0, and 4 gauge ground to chassis, with a .1-.05 Ohm resistance to the OE ground points on the core support, with matching resistance from battery ground to chassis, figured that ground was good enough. If not, I guess I can run another ground wire directly to the battery if that will actually help.
    Last edited by 98Firebird; 09-17-2019 at 12:43 AM.

  8. #8
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    Quote Originally Posted by 98Firebird View Post
    OK, does the ground that goes to the battery need to be independent (so two 10 gauge grounds, ran directly to the remote mounted battery) of the other bank.
    Yes, that's how it's supposed to be.

    Or can they both ground to a single wire (4 gauge?) that then runs to the battery?
    That should be fine to support the amperage draw.
    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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