HP EFI SMART COIL HIGH POWER SUB HARNESS P/N 558

HP EFI SMART COIL HIGH POWER SUB HARNESS
P/N 558-318
Overview
PN 558-318 contains two terminated harnesses designed for use with Holley HP Smart Coils (PN 556-112) used on 8 cylinder engines.
One end plugs directly into the Holley smart coil. The other end is terminated with a 7-pin metripak connector and three loose 12ga
wires. The 7-pin connector plugs into the Holley Universal Coil-On-Plug harness (PN 558-307, not included), Holley LSx main
harnesses, or factory GM LSx harnesses. The layout of the harness is similar to factory GM LSx coil harnesses with some added
length for coil mounting flexibility.
Installation
1.
The coil connectors are marked based on engine type (GM/Others with 1-3-5-7 and 2-4-6-8 cylinder banks and Ford with 1-23-4 and 5-6-7-8 cylinder banks). Install these as marked. The 7 pin metripak connectors (it has 8 cavities and 5 are
populated) are labeled “GM EVEN” and “GM ODD”. The “GM EVEN” plugs into the “DIS CONNECTOR EVEN” on the 558307 harness or “IGNTION EVEN” on Holley LSx main harnesses. The “GM ODD” goes into corresponding “ODD” connectors
on these harnesses.
2.
12 gauge BROWN ground wire – This ground MUST go to the cylinder head that the coil is discharging to. This connection
should be independent of other grounds. Do NOT connect this ground wire to sheet metal, or other locations that may not
have a solid ground path to the battery. If this wire needs to be extended, use 10-12 gauge wire and appropriate connectors.
3.
12 gauge BLACK ground wire – This high current ground should go to the battery or to a ground stud that is directly connected
to the battery. This connection should be independent of other grounds and as close to the battery as possible. Do NOT
ground on sheet metal, etc. If this wire needs to be extended, use 10-12 gauge wire and appropriate connectors.
4.
12 gauge RED power wire – Do NOT connect directly to the battery. Install with fused relay(s) as described below
A) 5msec of dwell or less can be wired with a single fused 40A relay for 8 coils
B) Over 5msec of dwell should use a single fused 70A+ relay for 8 coils or two 40A relays with 4 coils on each.
Connector Pinouts
These are pre-terminated.
Coil Connectors



Pin A –
Pin B –
Pin C –

Pin D –

Pin E –
Coil Trigger – Connect to individual ECU EST Outputs. EST A should go to cylinder #1, EST B to cylinder #2, etc.
Coil Trigger Ground (Black w/ white tracer) – These can be all tied together and go to Pin B14 (EST Ground Output).
Ground to Cylinder Head (Brown) – This ground MUST go to the cylinder head that the coil is discharging to. It is
recommended to tie each cylinder bank together. Do NOT connect any other grounds to this point. This MUST be
the only ground in this location.
Battery Ground (Black) – This high current ground should go to the battery or to a ground stud that is directly
connected to the battery. Do NOT ground on sheet metal, etc.
High current switched +12V Power (Red) – Do NOT connect directly to the battery. On applications with 5msec of
dwell or less, it is recommended to install to a fused 40A relay source to power all 8 coils. On applications over
5msec, it is recommended to use a single fused 70A+ relay for 8 coils or two 40A relays with 4 coils on each
Metripak Connector Pinouts
This information is contained with the 558-307 harness. If you do not have these instructions, they can be found on www.holley.com,
under “Technical”, then “Instruction Sheets”, and type in 558-307.
Technical Support
1-270-781-9741 or 1-866-464-6553
www.holley.com
© 2016 Holley Performance Products, Inc. All rights reserved.
199R10219
Date: 11-15-16