PRO HV-4 Injector Driver

Key benefits

• Crisp idle with large injectors: at idle the pulse is short. With the injector opening fast and always the same way, the ECU meters small amounts of fuel more precisely.
• More linear map: with less dead time, fuel delivery follows injection time more proportionally, with fewer workarounds in the tune.
• Injectors flowing evenly: dead time is the main reason one injector flows differently from another. By reducing it, the PRO HV-4 reduces the error of each pulse, and injectors flow more evenly (in volumetric testing, often better than when they were new on the original driver). Works with low- and high-impedance injectors.
• Run a single set of injectors: with short-pulse precision, the high-flow set also handles idle, without a low-flow set.
• Stable mixture when battery voltage drops: turn on the A/C, the radiator fan or the headlights and battery voltage drops. On the PRO HV-4, opening comes from boost voltage regulated by the internal DC-DC converter, and peak and hold currents are regulated by the module, so injector opening does not depend on battery voltage within the 8 to 30 V range.
• More fuel at high RPM, same injector: the injection window shrinks at high RPM, but dead time does not. The time the module gives back on each pulse becomes injected fuel, with the same injector and the same duty-cycle limit.
  

Features

• 4 injector channels and 1 channel for the high-pressure pump control valve.
• Direct injection (GDI) and port injection (PFI) on the same hardware, with channels firing in any order and with overlap.
• Boost up to 65 V; boost, peak and hold currents configurable up to 25 A each; 8 to 30 V supply.
• Per-channel diagnostics (open circuit and short circuit), boost failure, low battery and temperature, with LED and CAN network alerts. You know exactly which injector failed.
• Configuration via FTManager, VisionFT or the DBC file in third-party tools.

Who it's for

• Anyone who installed large injectors to chase power and can't get a smooth idle.
• Builders and tuners who want every injector flowing the same as the next, with less cylinder-by-cylinder trim in the map.
• Power builds that want to run a single bank of high-flow injectors.
• Race teams that need precise short pulses and more usable injection time at high RPM, with the same injector.
• Builds running direct injection and port injection that currently use two modules.
• Engines with up to 4 cylinders in sequential mode. For a V8, use two PRO HV-4 units.

Important: what you need

The PRO HV-4 is not plug-and-play. It requires the dedicated PRO HV-4 harness, sold separately, or a harness built with the PRO GEN2 connector and terminals kit, plus readjustment of dead time and the fuel map in the ECU. FuelTech recommends installation by a qualified tuner.

• Port injection (PFI): PowerFT VCUs and the VisionFT line.
• Direct injection (GDI): VisionFT line only.
• Third-party ECUs: compatibility depends on the electrical characteristics of the injection outputs and on the ECU's functions.
• Each channel receives its command through a wire from the ECU injection output. The CAN network is used for configuration and diagnostics; it does not trigger injection.
• Solenoid injectors only; not compatible with piezoelectric injectors.
• The pump channel is exclusively for the high-pressure pump control valve. Never connect an electric fuel pump to the module channels.

The gain is electrical: the PRO HV-4 does not change the injector's static flow and does not fix a clogged injector. Dead time values and gains mentioned depend on the injector, fuel pressure and tune.

Technical specifications

What's in the box

• 1 PRO HV-4 Injector Driver module
• 1 Installation and operation manual

The dedicated harness and the PRO GEN2 connector and terminals kit are not included; they are sold separately.

Installation notes

• Install with the battery disconnected and the harness unplugged from the module. Warning: injector outputs operate at up to 65 V and internal capacitors may hold a charge for some time after power-off. Do not handle the injector harness with the module powered.
• Run power ground directly to the battery negative terminal, without splices (not to the chassis, engine block or cylinder head).
• Keep the harness as short as possible; cut off excess length and do not coil the wires.
• Protect against heat, moving parts and sharp edges; use protective sleeves and grommets.
• After installation, readjust the dead time and check the fuel map in the ECU.

FAQ

What is the PRO HV-4 Injector Driver?
A boost injector driver with up to 65 V for direct injection (GDI) and port injection (PFI) solenoid injectors. It opens the injector faster and identically on every pulse using the Boost → Peak → Hold strategy, with 4 injector channels and 1 channel for the high-pressure pump control valve.

Does it work with my ECU?
It needs one injection output per channel, connected to the module input. Port injection: PowerFT and the VisionFT line. Direct injection: VisionFT line; on the FT700, in Beta mode, enabled by technical support. PowerFT units do not support direct injection. Third-party ECUs: depends on the electrical characteristics of its outputs and on its functions.

Is it plug-and-play?
No. The module uses a 26-pin connector and does not come with a harness: use the dedicated PRO HV-4 harness or build one with the PRO GEN2 connector and terminals kit Since the injector will open faster, you must readjust the dead time and check the fuel map in the ECU.

Which injectors does it support?
Direct and port injection solenoid injectors, low or high impedance, with the correct parameters for each injector. Not compatible with piezoelectric injectors.

What is dead time?
The delay between the ECU command and the actual opening of the injector. The longer and more variable this delay, the greater the metering error, especially at idle, where pulses are short. With boost, the PRO HV-4 shortens dead time (on port injection, from about 1.4 ms to as low as 0.3 ms) and makes it independent of battery voltage.

How much more fuel at high RPM?
Illustrative example with port injectors (4-stroke engine, 85% maximum duty cycle, 120 lb/h injector, dead time going from 1.4 to 0.3 ms): about 7% more usable flow at 6,000 RPM and about 11% at 9,000 RPM. The injector's static flow does not change. Actual results depend on the injector, fuel pressure and tune.

PRO HV-4 or PRO HV-8?
Both use the same technology and the same Boost → Peak → Hold strategy. PRO HV-4: 4 injector channels and 1 pump valve channel, in a more compact module, for engines with up to 4 cylinders. PRO HV-8: 8 channels and 2 pump valves, for up to 8 cylinders in a single module or builds with two high-pressure pumps.

Can I use two on a V8?
Yes. Each PRO HV-4 handles 4 cylinders with its own boost stage and can be mounted close to its bank, with a shorter harness. If you prefer a single module for all 8 cylinders, choose the PRO HV-8.

Does it replace the Peak and Hold PRO?
It depends on the application. Port injection that does not need boost: Peak and Hold PRO. Large injectors with a hard-to-tune idle, injectors flowing evenly, a single injector bank or direct injection on up to 4 cylinders: PRO HV-4. More than 4 cylinders in a single module or two high-pressure pumps: PRO HV-8.

What happens if an injector fails?
The module detects open circuit and short circuit on each channel, boost failure, supply voltage drop and temperature, and reports which channel failed through the LED and the CAN network. You choose whether it only warns or shuts down; by default, only a boost failure shuts down the module.

Your injector always had more to give. It was missing the driver.