Holley 3.5 Touch Screen LCD User Manual

User manual for the Holley 3.5 Touch Screen LCD, covering installation, tuning, adjustments, and diagnostics for vehicle engine management.

Brand: Holley
Category: Car parts
Document type: User Manual
Language: English
Pages: 36
File format: PDF
File size: 1.2 MB
Published: 15 October, 2026
Updated: 15 October, 2026
MD5 checksum: A9D8B3E0CFC115902A82B56E1D42D8EA
PDF: Holley 3.5 Touch Screen LCD User Manual PDF

About this manual

This manual provides instructions for the Holley 3.5 Touch Screen LCD (part number 553-108), a handheld device used for engine tuning and monitoring. It details the package contents, mounting procedures, and connector requirements, specifically the CAN1/Power harness and CAN adapter harness.

What's inside

Quick Start Guide
Package Contents
Mounting
Connectors
Making Adjustments
Home Screen
Basic Tuning
System Tuning
Advanced Tuning
Diagnostics

Specifications

Part Number	553-108
Connector Type	4 pin Mizu-P25 male receptacle
CAN Adapter Harness Part Number	271R1075A
Power Connection	White wire to switched +12V, Black wire to negative

Frequently asked questions

How do I connect the 3.5 Touch Screen LCD to power?

Connect the black wire to negative and the white wire to a switched +12V circuit using the supplied harness.

What is the purpose of the Fuel Prime function?

Fuel prime injects a small shot of fuel into the intake manifold when ignition is turned on to wet the intake and allow quicker starting.

Can the touch screen be recalibrated?

Yes, the touch screen may be recalibrated by following the on-screen prompts in the Local Setup menu.

What happens if the ECU and touch screen firmware do not match?

The 3.5 functionality will be locked if the ECU and touch screen firmware do not match.

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