The Holley Sniper EFI system offers various installation and wiring configurations, particularly concerning ignition systems. This article details procedures for distributor removal, installation of adjustable rotors, wiring connections for different ignition types—including those with and without timing control—and initial EFI setup procedures. The documentation emphasizes careful wiring practices and provides resources for further assistance, including video tutorials.
Distributor Removal and Installation
The installation process often begins with the removal of the existing distributor. This involves disconnecting spark plug wires and all associated wiring or vacuum hoses. The distributor hold-down must then be removed, allowing the distributor to be lifted and removed from the engine.
When reinstalling or installing a new distributor, attention must be paid to the balancer diameter and distance. Specific measurements are provided for 6”, 7”, and 8” balancers, requiring distances of 3/4”, 15/16”, and 1-1/16” respectively. The documentation details a distributor lock-out procedure, which involves removing the rotor and advance components—including springs, weights, lock nut, and the advance stop bushing—from the advance assembly.
An adjustable rotor, specifically MSD PN 84211 or PN 8421, may be installed onto the distributor shaft. Proper seating of the drive shaft and distributor is crucial during installation. The documentation instructs to connect the 10-pin distributor connector to the Holley #558-493 adapter harness, noting that installation of the 558-493 harness should be completed beforehand. Clockwise rotor rotation requires turning the housing until the Crank LED turns OFF, aligning the rotor contact appropriately. Finally, the cap is installed, followed by the spark plug wires connected according to the engine’s firing order and rotor rotation. Reconnecting the coil power and ground completes the mechanical installation.
Wiring Configurations for Different Ignition Systems
The Sniper EFI system accommodates various ignition system types, requiring different wiring approaches. A key distinction is made between timing-controlled and non-timing-controlled ignition systems.
For non-timing-controlled systems, the yellow wire marked “Coil-” functions as an RPM input wire. This configuration is suitable for stock-type mechanical advance distributors with stock inductive ignition coils, such as older points distributors. Alternatively, for ignition boxes with tachometer outputs (like MSD, Accel, or similar capacitive discharge systems), connection is made to the “Tach Out” terminal using the included Ignition Adapter / Purple Wire.
The documentation recommends completing the installation with the engine running without timing control initially. This approach simplifies troubleshooting if issues arise. Holley suggests using a Holley Dual Sync distributor if utilizing Hall Effect input for the RPM signal, but acknowledges that the Sniper EFI can accept a 1x per fire Hall Effect signal from other devices, with compatibility verification remaining the responsibility of the customer.
Specific wiring diagrams are referenced but not included in the provided documentation. The system also features a digital gauge output for use with Holley EFI analog gauges via the 554-130 Gauge Module. An 8-pin connector (applicable to PN 550-852, 550-853 & 550-854) utilizes a mating harness PN 558-492.
Handling Unused Wires
Proper management of unused wires is essential to prevent future problems. Two options are presented: careful crimping or soldering to prepare for potential future use, or secure bundling and isolation.
Connecting the Handheld Display
The Sniper EFI touchscreen LCD connects to the main harness via a plug-and-play connection. For permanent installation within the vehicle, the Display CAN bus connector should be passed through a factory firewall grommet, and any excess wire secured to prevent damage.
Initial EFI Setup and Calibration Wizards
The initial EFI setup begins by turning the ignition key to the “run” position, which powers the Sniper EFI Touch Screen LCD. The Home Screen appears, providing access to various functional features. The system utilizes Calibration Wizards to guide the user through the setup process.
The wizard prompts for the system type, number of cylinders, engine displacement, and ignition system type. Ignition system options include Coil (-), CD Ignition Box, Magnetic (ECU Controlled Timing), Holley Dual Sync (ECU Controlled Timing), and HyperSpark (ECU Controlled Timing). The wizard also requests the power adder type, with a “None” option for naturally aspirated engines.
Datalogging and File Transfers
The Sniper EFI system supports datalogging, with a video tutorial available online (https://www.youtube.com/watch?v=rHjLwJQ45Kw&list=PLNMSNx7tRu2sxs6NmwrT3Gi-oO2x0ea). Datalogging is initiated and stopped via the 3.5” TSCLCD.
Configuration files can be transferred between the Sniper EFI throttle body and an SD card. To save a Global Configuration to an SD card, the user navigates to the “File” icon, then “Global Configs” on the handheld. The desired configuration is highlighted and saved. To load a configuration from the SD card into the Sniper EFI, the saved configuration file (located in the Saved GCF folder) is placed in the Sniper EFI Config File Folder (typically found in Documents > Holley > Sniper > Config Files). The Sniper EFI Software is then used to open the configuration file. Calibration can be viewed and modified within the software and saved back to the SD card or directly to the Config Files folder. A copy of the tune must also be placed on the SD card for transfer to the Sniper EFI via the handheld.
Fuel System Installation Considerations
The documentation also addresses fuel pump and filter installation. The fuel pump must be mounted lower than the lowest point of the fuel tank and as close to the tank as possible. Proper fuel tank venting is also required. Drilling into the fuel tank is cautioned against, with a recommendation for professional cleaning if this method is chosen. Alternatively, the tank can be drained, dried, and filled with water before drilling. Fuel line installation involves hose clamps and AN hose ends, as noted in the documentation.
Graph Options and Adjustment Methods
The Sniper EFI system provides graph options for data visualization and adjustment. These options include digital adjustment of individual data points or the entire curve, and graphical adjustment using a touch screen or stylus. Entire curve adjustment allows for locking and manipulation of the entire curve simultaneously.
General Wiring Best Practices
The documentation stresses the importance of a clean and constant voltage source and proper grounding for optimal system performance. Grounds are considered as critical as power connections. The wiring should be installed to separate “dirty” or noisy circuits from sensitive components within the Sniper EFI system.
Conclusion
The Holley Sniper EFI system offers a comprehensive engine management solution with adaptable wiring configurations for various ignition systems. Successful installation requires careful attention to detail, particularly regarding distributor installation, wiring connections, and initial setup procedures. Utilizing the provided resources, including the Calibration Wizards and online video tutorials, will aid in a smooth and effective installation process.