Ignitions and Electrical Wiring Harnesses

BP Automotive

Standalone Engine Harness 5.7L LS1/LS6

$550.00

SKU: H300

In Stock
In Stock
Ships by Aug 5
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INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

The BP Automotive H300 is a meticulously engineered standalone engine harness crafted for the seamless integration of GM Gen III EFI engines into custom builds. Designed for 1997-2006 5.7L engines featuring RPO codes LS1 and LS6, this harness specifically accommodates Drive by Cable (mechanical) throttle bodies, EV1 injectors, and the 4L60e automatic transmission. Constructed with GM color-coded TXL wire that meets or exceeds OEM standards, the H300 ensures reliability and durability. It features Connector Position Assurance Locks (CPA Locks) for secure connections and a sliding Delphi grommet to effectively seal the firewall penetration. The harness extends 5 feet from the rear passenger side of the intake, and includes an OEM fuse block complete with covers, labeling, and splash guards for a robust, weather-resistant installation. This standalone harness is intended for pre-emissions vehicles or off-road use, as it does not include provisions for EGR, AIR, EVAP, or Rear O2 Sensors. While these can be added at an additional cost and may incur extended lead times, they are typically not required for such applications. The installation requires the removal of the VATS and emissions systems from the PCM and necessitates the use of a specific PCM service number (12200411 or 9354896). Additionally, the electronic automatic transmission requires a double pole (4-terminal) brake switch for converter lock-up control. Key connections included are for the Throttle Position Sensor, Idle Air Control Valve, Coolant Temperature Sensor, Alternator/Generator, all 8 Injectors (EV1 connectors), Coil Harness Connectors (Bank 1 & 2), Knock Sensor, Camshaft Position Sensor, 4L60e Transmission Speed Sensor, Upstream Oxygen Sensors (Bank 1 & 2), Mass Air Flow, IAT (if using a 3-wire MAF), MAP Sensor, Crank Position Sensor, A/C Pressure Sensor, OBD II Port, and two Harness Grounds to the driver cylinder head, along with a single battery constant connection. Connections requiring user hookup include Fuel Pump, Switched Ignition, TCC Brake Switch, Malfunction Indicator (CEL), Speedometer, Tachometer, and Fan Relay Controls.

MIA's Description

The BP Automotive H300 is a standalone engine harness designed for installing GM Gen III EFI engines. This harness is specific for 1997-2006 5.7L engines with RPO codes LS1 and LS6, featuring a Drive by Cable throttle body, EV1 injectors, and a 4L60e transmission.

The harness includes OEM Aptiv, Kostal, Bosch, Molex, and Yazaki connectors, along with Connector Position Assurance Locks (CPA Locks) and a sliding Delphi grommet for firewall sealing. The unit is 5 feet long and comes with an OEM fuse block.

Fitment

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Specifications

BrandBP Automotive
Part NumberH300
CategoryIgnitions and Electrical

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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