A practical starting checklist for an engine that cranks but will not start with a Haltech ECU. Work through setup, RPM, trigger signals, diagnostics, base ignition timing and fuel pressure before attempting another start.
Last reviewed: September 20, 2026
Safety: Secure the vehicle, keep clear of moving parts and use short cranking periods. Stop if fuel leaks or unsafe conditions are present. This checklist is not a substitute for engine-specific setup instructions or a complete ECU configuration.
Elite and Nexus ECU series
Start by identifying your exact ECU model. Browse Haltech Elite series ECUs and kits at Paddock Tuning or Haltech Nexus series ECUs and kits at Paddock Tuning. These links open store search results, which may also include related accessories.
Available channels, functions and menu layouts vary by ECU model, firmware and software version. Follow the documentation for your installation; this checklist is not a recommendation to replace your ECU. The Elite 550 and 750 input-state-only oscilloscope note is included below.
1. Identify the setup
- What ECU do you have?
- What engine is installed?
- Who made the wiring harness?
- Is RPM displayed while cranking?
2. If there is no RPM, check the trigger system
Is the trigger pattern stock or aftermarket? If aftermarket, do you know the pattern? Identify whether the crank and cam sensors are Hall effect or reluctor rather than guessing.
Open the oscilloscope in NSP and select:
- Channel 1: Trigger Voltage
- Channel 2: Trigger Input State
- Channel 3: Home Voltage
- Channel 4: Home Input State
Elite 550 and 750: Use the input-state channels; voltage channels are not available.
Crank the engine and check for waveforms. Input-state waveforms alone do not identify the physical sensor type. Verify trigger settings match the actual engine, trigger pattern, sensor types and wiring. Do not copy example tooth counts, edges, pull-up settings or TDC angles without verifying they apply to your installation.
Crank again. RPM should now be present. If it is still missing, remain in trigger troubleshooting before continuing.
3. Check the Diagnostics page
Open the Diagnostics tab. If it is missing, click Add New Page, select Diagnostics from the dropdown, then press OK.
Verify In-Air Temp, CTS (coolant temperature) and TPS (throttle position) readings are correct. Correct configuration or wiring problems, and install required missing sensors, before continuing.
Need a compatible sensor? Browse all air temperature sensors or all CTS / coolant temperature sensors at Paddock Tuning. Check thread size and pitch, connector, installation requirements and the correct ECU calibration before selecting a sensor. Do not replace a sensor until testing identifies the fault.
While cranking, check:
- RPM is present.
- Trig ErrsCnt is ideally 0. One or two isolated errors may occur at power-on or when cranking stops, but the count must not continuously increase while cranking.
- EngLim Fn says None.
- Trig SyncLev says Half or Full, as appropriate for the configured trigger system.
- Trig SyncState says Running while cranking.
If trigger errors continue increasing, return to trigger troubleshooting.
4. Verify base ignition timing
- Disable injectors under Engine Configuration > Fuel System.
- Enable ignition timing lock under Ignition Tuning. Choose a known, clearly marked crank-pulley angle suitable for the engine.
- Crank the engine and check actual timing with a timing light.
- Under Engine Configuration > Trigger System, adjust TDC Angle until actual timing matches the locked timing. Confirm it stays consistent.
- Disable ignition timing lock under Ignition Tuning.
- Re-enable injectors under Engine Configuration > Fuel System when ready for the starting check.
Verify actual timing with the timing light—not just the number entered in software.
5. Do you have fuel pressure?
Verify fuel pressure is present and appropriate for the installed fuel system. Pump noise alone does not confirm pressure. If pressure is missing or incorrect, resolve the fuel-system issue before continuing.
For electronic fuel-pressure monitoring, browse fuel pressure sensors at Paddock Tuning. Choose the appropriate pressure range, thread size and pitch, connector and fuel compatibility, and configure the matching calibration in the ECU. An ECU pressure sensor is not required if you are checking pressure with a suitable mechanical gauge.
6. Attempt to start the engine
At this point, the engine should start or show signs of trying to start, provided the remaining ECU configuration is correct. RPM and trigger signals alone do not guarantee the engine will start.
If you are still having trouble, email Paddock Tuning at sales@paddocktuning.com or contact Haltech Support for further assistance.
Common Haltech no-start questions
Why does my Haltech show RPM but not start?
RPM confirms the ECU sees a crank signal, but the engine can still fail to start because of trigger synchronization, incorrect base ignition timing, missing fuel pressure, injector or ignition configuration, or incorrect sensor readings.
What should Trigger Error Count read while cranking?
Trig ErrsCnt should ideally remain at 0 while cranking. If it continuously increases, return to the trigger pattern, sensor type, wiring, edge and pull-up checks before attempting another start.
What should Trig SyncState show?
Trig SyncState should show Running while cranking, with Trig SyncLev at Half or Full as appropriate for the configured trigger system.
Official Haltech references
- How to use your NSP Oscilloscope — Haltech
- Hall Effect or Reluctor? — Haltech
- Calibrating Ignition Timing — Haltech
These links open official Haltech documentation. This checklist is Paddock Tuning content, not an official Haltech publication. Follow the documentation for your ECU and software version.
Safety and scope
This guide provides general troubleshooting information, not engine-specific tuning instructions. Incorrect wiring, trigger configuration or ignition timing can cause injury or engine damage. Follow the manufacturer’s instructions and use a qualified technician where needed. Stop for fuel leaks, unstable timing or other unsafe conditions. Paddock Tuning is not affiliated with or endorsed by Haltech through this article.