Holley EFI Diagnostic and Support

Having trouble with your Holley EFI system? Our Holley EFI Diagnostic and Support service is designed to help identify configuration, wiring, firmware, fueling, and drivability problems without guessing or repeatedly replacing parts.

We support Holley EFI systems including Terminator X, Terminator X Max, HP EFI, Dominator EFI, Sniper EFI, and other Holley EFI-equipped vehicles.

Diagnostic Support Includes

• Wiring and electrical troubleshooting

• ECU communication problems

• ECU recovery after a failed or interrupted firmware update

• Bricked or unresponsive ECU diagnosis

• Engine breaking up, misfiring, or losing power

• Rich or lean air-fuel ratio concerns

• AFR target and fuel table recommendations

• Injector and fuel-system configuration review

• Sensor calibration and sensor reading verification

• Trigger, crank, and cam synchronization problems

• Datalog review and troubleshooting

• Startup, idle, drivability, and wide-open-throttle concerns

• Holley software and configuration assistance

Wiring Issue Diagnosis

Incorrect power, ground, relay, injector, ignition, crank, cam, or sensor wiring can cause intermittent issues that are difficult to diagnose. We can review your wiring, ECU configuration, pictures, diagrams, and datalogs to help locate the problem.

Common wiring-related symptoms include:

• ECU disconnecting from the laptop

• Injectors or ignition coils not receiving power

• Fuel pump not operating correctly

• Engine cranks but does not start

• RPM signal dropping out

• Sensors displaying incorrect values

• Random resets or electrical interference

• Engine breaking up under load

Bricked ECU and Firmware Update Support

If your Holley ECU stopped communicating after a firmware update, we can help determine whether the ECU can be recovered through the Holley software or whether it requires additional service.

Do not repeatedly power-cycle, reflash, or modify the ECU until the issue has been evaluated, as this may make recovery more difficult.

AFR and Fueling Recommendations

We can review your current calibration and datalogs to provide recommendations for:

• Target air-fuel ratio

• Closed-loop compensation

• Learn-table settings

• Base fuel table corrections

• Startup and warm-up fueling

• Acceleration enrichment

• Idle fueling

• Boosted and naturally aspirated applications

What You Will Need

Depending on the issue, you may be asked to provide:

• Current Holley configuration file

• Datalogs showing the problem

• Pictures of the ECU, wiring, connectors, relays, and grounds

• Vehicle, engine, injector, ignition, and fuel-system information

• A detailed description of when the problem occurs

• Any recent firmware, wiring, engine, or calibration changes

Remote computer access may be requested using AnyDesk when real-time software support is needed.

Important Information

This service covers diagnostic review, technical support, and calibration recommendations. Replacement parts, physical wiring repairs, ECU repair, dyno tuning, and complete custom tuning are not included unless purchased separately.

Diagnostic results depend on the accuracy of the information, files, pictures, and datalogs provided. Some electrical or mechanical problems may require in-person testing with professional diagnostic equipment.