Results 1 to 3 of 3

Thread: Smart Coil Sub-Harness 558-312

  1. Default Smart Coil Sub-Harness 558-312

    I'm just going over some wiring in my car and tidying up. I just want to clarify that the Sub-Harness 558-312 Pin "E" is supposed to be connected to a switched +12V source, and not a Crank/Run +12V source correct?
    '84 Ford Mustang

  2. #2
    Join Date
    Dec 2009


    Yes, switched power in crank & run key positions. The ignition coils must be powered to start the engine. (Holley 558-312 CNP Coil Sub-Harness Instructions)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Moser 31 spline axles, Cobra Trac-Lok differential, 4-disc brakes/Cobra booster/MC, 5-lug Bullitt wheels & 245/45R17 tires.

  3. Default

    OK thanks. Just trying to determine why my key in ignition is so hit or miss when trying to start the car. Like it would just click and then the odd time it would actually engage. I already replaced tumbler/ignition switch, so it must be wiring related I guessing. Going to replace the wire to starter (Powermaster starter with no factory solenoid). I've already driven the car, etc., it's just the damn key in ignition starting that's acting up.

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