When it comes to the 1HD-FTE Toyota LandCruiser engine, there’s plenty of talk about tuning, but also a fair bit of confusion about what that really means. The 1HD-FTE engine is found in everything from the HDJ78 Troopcarrier, HDJ79 utes, all the way to the 100 Series wagon and has been earning a reputation for it’s strength and reliability since its release in 1998. But in factory form it’s far from a powerhouse. There’s a lot of untapped potential in these engines, yet the way that potential is unlocked is often misunderstood, especially when it comes to the term “remap.”
The term ‘remap‘ as a whole has become so closely associated with diesel dyno tuning that it is often one of the first things our customers ask us about when it comes to increasing the power in their 1HD-FTE engine, or, something I see posted into forums a lot for example is “Should I get a remap or a Unichip, what are peoples experiences like?”
Well, today I thought I might clear up some of that confusion surrounding this topic and explain exactly what is going on when you a tune a 1HD-FTE, and what the difference between a ‘remap’ is and tuning with a piggy back ECU such as a Unichip is on this engine.
To start off with, a ‘remap‘ is the short word for recalibrating the factory data in the manufactures own Engine Control Unit (ECU) via either an actual ECU read or virtual ECU read, applying the read data into an editing suite such as WinOLS5, ECM Titanium, BitEdit or others, it is then manipulated to the programmers specifications, and written back into the vehicle by way of a communication protocol usually via the OBD plug. This sort of reprogramming is available to vehicles such as a VDJ79 Toyota Landcruiser, VDJ200 Toyota Landcruiser, or really all Toyota diesels from 2006 onwards. You can see how easily this can get muddled up with the 1HD-FTE.
The 1HD-FTE’s engine control unit (ECU) does not allow this sort of back and forward communication of it’s factory ECU data. There is no available tooling or means to write a file into the 1HD-FTE’s ECU beyond what the manufacture itself has available. It’s not that it’s not possible to edit the file itself as binary editing programs such as WinOLS5 would technically allow the editing of such a file if it was available, but still, there’s just no way to write it back into the ECU even if you did have it. Which no one does, as far as I know.
This leaves us with one available option. A piggy-back ECU, specifically a UniChip UNI-X. The way a Unichip UNI-X allows us to tune a 1HD-FTE is by piggy-backing off the back of the relevant and important ECU data by intercepting sensor and control signals as they leave and arrive to the ECU.
These relevant signals are,
- Throttle position sensor 1 (TPS) – This reads your throttle position.
- Throttle position sensor 2 (TPS) – This reads your throttle position. (It’s a 2 way sensor)
- Manifold Absolute Pressure Sensor (MAP) – This tell the ECU how much boost pressure is being made.
- Engine Coolant Temperature (via coolant sensor) – This tells your ECU how hot your engine is running.
- Engine Speed (via crank angle sensor) – This tells your ECU how fast the engine is spinning.
- Injection Quantity (via spill valve) – This controls how much fuel is outputted via the pump per revolution.
- Boost Pressure (by adding a 3-Way 33HZ MAC Valve) – An add on feature of the UniChip UNI-X
- Injection Timing (via crank angle sensor)
This allows the piggy-back Unichip UNI-X ECU to interpret and adjust these relevant signals to the users desired results with precise accuracy. Plus, it adds a huge bonus to the tuning process as it now allows for LIVE changes, and unique features such as Multi-Mapping giving you the benefit of 5 tunes on a switch for features like immobilisers, max power, towing modes, off-road modes, or the ability to return the vehicle back to stock power for a valet mode. None of which a factory ECU can provide you without seriously major R&D work and back engineering of factory software. So in a way, even if factory remapping was available, the Unichip offers huge advantages beyond just a solution to a problem.
There are now various different approaches to how the tuning is then carried out inside the Unichip UNI-X tuning software. Without letting all our secrets out, there are a few fundamentals that we follow to ensure longevity, reliability, and smoke free solutions to everything from a standard vehicle upgrade to a huge 450HP build.
Approach A) Utilising the throttle position as a load reference for fuel control and boost control.
This is the approach we take when tuning a standard injector HDJ100, HDJ79 or HDJ78 Toyota Landcruiser. The reason for this is when running the standard injectors, it is actually quite difficult to ‘overfuel’ the engine with the increased boost pressure of a standard or upgraded turbo such as a UFI 16G or 18G. They really aren’t big enough , therefore we want to drive in as much efficient fuel flow as possible as quickly as we can to spool the turbo up quickly. The easiest way to do this, is by referencing when you, the driver, puts your foot down. Pretty simple philosophy, ‘put ya foot down for more power’.
Approach B) Utilising the MAP sensor as a load reference for fuel control, throttle position for boost control.
If you are increasing the performance of your 1HD-FTE it is going to need higher flowing injectors. As the 1HD-FTE engine has a mechanical hydraulically controlled fuel injector (mechanical non-solenoid 2 spring injector), it means we do not have individual control over the injector open times (measured in Us in diesels or m/s in petrol engines) directly. We are entirely dependant on two things for fuel control – how much the factory ECU wants to input based off the MAP sensor voltage, and how much longer we are opening the spill valve to allow fuel up to the injectors.
Therefore, when it comes to tuning the 1HD-FTE with larger injectors, we opt to scale our load axis (x axis) in the fuel table to be looking up it’s load reference from the MAP sensor voltage. This sensor reads from approx. 2.29v at atmospheric pressure while at idle, has a factory boost cut built into the ECU at 3.61v (202.325kPa or 14.7PSI boost pressure) and up to a maximum of 4.8 volts. It is a 2 Bar Map sensor.
This means two things – fuel will only be added as boost is naturally made by the engine rpm and load, giving us essentially ‘fuel to boost compensation’ as the engine rpm increases, but it also means we can restrict how much voltage the factory ECU sees going back to it in ‘off boost’ situations such as engine speed below 1800rpm or light throttle cruise, allowing us to limit our off boost fuel. This also means the fuel control table can also be mapped in ‘3D’ giving us a dynamic approach to fuel control.
Retaining the throttle position for the load reference on the boost control table is important so we can start demanding a certain amount of boost from the moment the action to accelerate has begun (putting your foot down).
Irrespective to your engine setup, all the inputs to the UniChip need to be accurate and precise or else you will encounter problems. For example, not wiring your engine speed signal correctly will mean the UniChip is not referencing engine speed – therefore it will not travel across the Y axis of the relevant Maps, it will just go up and down on the X axis as it reads load but not RPM. Or, not wiring your throttle position or Map sensor correctly will mean there’s no reference for the X axis causing it to only travel up and down the bottom row of the Map as it reads engine speed, but no load reference. Not wiring your coolant temperature protection correctly will mean the UniChip will derate it’s power, because it will assume the temperature is reading high and zero out the fuel map to protect it. Not only is it important to ensure you have wired these correctly, but it is equally important to ensure all the wiring to the MAP sensor, throttle position sensor, coolant temperature sensor, crank angle sensor are all undamaged and the plugs are clean.
There is a little bit more as to how these are tuned, but it is largely irrespective to understanding how the UniChip controls your engine and more about our unique approach to throttle control, timing control and boost control, and that would just be letting too many secrets about our process out at once, unfortunately. But to summarise what we have available is,
- Injection Timing Control
- Fuel Control
- Throttle Control
- Boost Control
- Engine Temperature Protection Modes
- 5 Maps with the ability to add an immobiliser in which the engine will not start
Not only is this article hopefully useful for someone considering an upgrade for their 1HD-FTE, but part of the inspiration to write it came from helping people on forums solve issues with their own car, and my hopes are it may also help yourself as the end user understand how your car works and assist in the potential need to diagnose your vehicle if a fault arrises.
For example, I was able to help someone solve a problem recently he had been dealing with since he fitted his UniChip. It had an intermittent power loss, once I had explained how the load reference for fuel was derived, he checked his MAP sensor plug, found corrosion, cleaned it, and that was all it ever was.
We provide the UniChip UNI-X as both a pre-tuned DIY option as well as a supplied, fitted and installed product in house.
Please see the link here to get more information on the UniChip UNI-X for the 1HD-FTE Toyota Landcruiser.
Diagnosing Common Issues with Poor Performance on a 1HD-FTE with a UniChip
- Check the hose to your MAP sensor. It runs around the front of the engine from a small white and grey filter, goes under the rocker cover to a hose that runs to a blue solenoid on the passenger side of the engine bay, then from the blue solenoid to the black 3 pin sensor on the back of the cross over pipe. It has likely fallen off due to it’s age and probably lost its tight seal onto the sensor. The hose will need to be replaced the whole way with 1mm ID vacuum hose. Also, try bypassing the filter altogether to rule out any cracks or blockages in it. It is common for these to crack and leak boost, look for hairline cracks on the bottom with oil coming out of them. A stainless steel replacement can be purchased here.
- Check you did not hook up your boost controller backwards. An easy way to remember the correct orientation is ‘wires to the waste gate’. This means, the side the wires come out of, is the side the hose from the waste gate runs too.
- Incorrect wiring – re check it, and check it again. If I hear one more ‘qualified auto sparky mate’ on the phone who won’t even check their own work I will probably have to turn it off for good. Watch our video here on how to wire it.
- Check you have no boost leaks.
- Check you have no fuel leaks around your fuel filter, or loose hoses.
- If you have a sudden ‘cut out of power‘ that instantly returns after you lift the pedal, check your intake isn’t sucking shut due to old hoses or restrictive snorkel piping.
- If your car suddenly shuts off around 2800rpm-3000rpm and throws and EDU circuit fault P1215, your injection pump will need replacing and can be purchased here.
- Lots of black smoke but not much power indicates you have a turbo related issue. Check your waste gate, make sure it is going 100% shut. People often rotate turbos unnecessarily causing the waste gate to leak open or have low tension on the actuator arm, prematurely opening it relieving boost too soon at too low of a pressure to compensate for fueling.
