TB45 at a glance
| Spec | TB45 |
|---|---|
| Layout | Inline 6 cylinder |
| Displacement | 273.3 ci (4479 cc) |
| Firing order | 1-5-3-6-2-4 |
| Common vehicles | Nissan Patrol and Safari, Y60 and Y61 |
There are two versions. The TB45S is carbureted, so it needs a full conversion to injection before any ECU makes sense. The TB45E is the fuel-injected engine, and that's the one this guide covers.
Plug-in or wire-in?
For an injected Patrol, a plug-in adapter harness saves a huge amount of time and keeps the factory loom intact. We carry the Elite 750 kit for the Y60/Y61 TB45, the Elite 2500 version if you want more I/O, and the Nexus S3 adapter harness kit. The sensor notes below apply whichever route you take, and they're essential if you're wiring from scratch.
Distributor: trigger, coil and igniter in one
Everything ignition-related lives in the distributor. It carries a dual optical pickup (a 120 degree reference signal and a 1 degree position signal), plus the coil and igniter. That means one connector covers trigger, home and spark.
| Pin | Function | Haltech side |
|---|---|---|
| 1 | Igniter signal from ECU | Ignition Output 1 (yellow/black) |
| 2 | Igniter ground to cylinder head | Not connected to the ECU |
| 3 | Coil 12V+ | Not connected to the ECU |
| 4 | Ignition check | Not connected to the ECU |
| 5 | REF signal, 120 degree | Trigger + (yellow, Trigger 4-core) |
| 6 | POS signal, 1 degree | Home + (yellow, Home 4-core) |
| 7 | Switched 12V+ sensor supply | 12V+ (red, Trigger 4-core) |
| 8 | Sensor ground | Signal ground (blue, Trigger 4-core) |
Running it all through one shielded cable
Optical pickups don't need a negative signal wire, so you can save running the second shielded cable. The Trigger 4-core already carries 12V+, signal ground and Trigger+; the only thing missing is Home+. Repurpose the green Trigger- wire as your Home+ by moving it to the Home+ pin at the ECU plug, and leave the Home 4-core unused.
- Elite 550, 750 and 950: pull the yellow wire out of A32 and insulate it. Move the green wire from A33 into A32.
- Elite 1000, 1500, 2000 and 2500: pull the yellow wire out of B2 and insulate it. Move the green wire from B5 into B2.
Once that's done, double-check the trigger and home arrive on the right inputs with the trigger scope before you ever try to start it. Haltech's trigger settings and dwell screenshots for this engine are worth having side by side with your map.
Need this diagram? Ask us and we'll send it over with advice for your build.
Throttle position sensor
The TB45 uses a cable throttle. What's on the throttle body depends on the transmission.
Manual trucks have a plain 3-pin sensor: pin 1 ground to signal ground, pin 2 signal to any spare AVI, pin 3 to the ECU's 5V+ supply.
Automatic trucks have a sensor with two 3-pin plugs. The lower plug is the full-range sensor you want. The upper one only has full-throttle and closed-throttle switches, used by the factory transmission logic.
| Sensor pin | Connect it to | What it carries |
|---|---|---|
| 1 | ECU signal ground | Sensor ground |
| 2 | A free analog voltage input (AVI) | Throttle position |
| 3 | ECU 5V+ supply | Sensor reference voltage |
| 4, 5, 6 | Leave unconnected | Full-throttle switch, switch supply and closed-throttle switch |
Manifold pressure
There's no factory MAP sensor. On a naturally aspirated or lightly boosted TB45, the ECU's internal MAP sensor is all you need (see our note on the Elite internal MAP sensor for its range). For higher boost, fit an external sensor such as a 5 bar MAP sensor on a spare AVI.
Idle air control
The idle valve assembly has two solenoids. Only one belongs to your Haltech.
- The larger solenoid (Nissan's IACV-AAC) does the actual idle control. It's a 2-pin valve driven with a duty signal from a single ECU output: pin 1 goes to a spare output, pin 2 to switched 12V+.
- The smaller solenoid (IACV-FICD) is the A/C idle-up. It has a permanent ground and gets 12V+ from the A/C relay, so it just switches with the compressor clutch. Leave it on the factory A/C circuit, not the ECU.
Temperatures
Coolant: the 2-pin sensor isn't polarity sensitive. One pin to a spare AVI, the other to signal ground. Use an AVI with a switchable pullup, or add an external 1k pullup to 5V, and load the matching temperature calibration from ESP.
Air temperature: the factory never fitted one. Add a sensor in the plenum or the intake pipe just ahead of the throttle body. Don't skip this; fueling and timing both lean on it.
Knock sensor
Nissan knock sensors ground through their metal body. To work out which pin is which, check continuity from each pin to the body: the one that beeps is the ground side, the other is the signal that goes to the Haltech knock input. Because the sensor is already grounded through the block, Haltech advises against adding a separate ECU signal ground to it. If you'd rather fit a fresh sensor, the Bosch knock sensor is our go-to.
Other sensors
- MAF: most Haltech conversions delete it, but you can keep it. Pin 1 no connection, pin 2 switched 12V+, pin 3 sensor ground, pin 4 the 0-5V signal to an AVI.
- Oxygen sensor: the factory unit is a single-wire narrowband and isn't good enough for tuning. If there's nothing better you can put it on AVI1 or AVI6, but we strongly recommend a WB1 wideband kit.
- Vehicle speed: a reluctor (variable reluctance) sensor. Signal+ to any spare SPI, signal- to signal ground. Calibrate pulses per distance from a known speed run rather than guessing.
Injectors, the OEM ECU and base maps
Injector flow is measured with the injector held fully open, and dead time covers the lag while the injector opens and closes plus the partial-flow moments in between. You don't have to measure either for the factory injectors: both are already in the base map that installs with ESP for the adapter harness kit.
If you're hunting for the factory ECU, it looks like the familiar RB25DET Skyline unit and uses the same connector. That's worth knowing when you're checking pinouts, but always confirm against the TB45 pinout itself rather than assuming it matches an RB.
Base maps built for the Elite adapter harnesses are the best starting point. Import one into your ECU rather than building from blank, then verify the trigger, TDC offset and sensor readings before the first start. Our base map basics article covers what a base map will and won't do for you.
Troubleshooting
| Symptom | Usually |
|---|---|
| No RPM while cranking | Trigger and home swapped, or the green wire not moved to the Home+ pin |
| TPS stuck at one value on an auto | Wired to the upper switch plug instead of the lower full-range plug |
| Idle hangs high with A/C off | FICD solenoid wired to an ECU output instead of the A/C relay |
| Coolant reads wildly wrong | No pullup enabled on the AVI, or the wrong calibration loaded |
TB45 FAQ
Can I turbo a TB45 on the internal MAP sensor?
Only at modest boost. Once you're near the internal sensor's limit, move to an external MAP sensor with headroom.
Do I have to keep the MAF?
No. Most Haltech TB45 builds run speed density on MAP and remove it.
Related engines: TB42, TB48 and the RB series. Questions about your Patrol? Get in touch.
