4AG Engine
The Toyota 4AG DOHC 16V engine
General Information
| Cylinders | 4 |
| Displacement | 1587cc |
| Firing Order | 1342 |
| Cylinder Orientation (from drivers seat) | Cyl1 closest to timing belt |
Model Variants
4AGE 1st gen Blue Early Big Port - USDM Vane MAF, JDM MAP, T-VIS @4200rpm, 9.4:1 comp. Batch fire injection, distributor ignition, 182cc injectors, 16 valve head
4AGE 2nd gen Red & Black Late Big Port - As above but all are MAP
4AGE 3rd gen Red Small Port - 10.3:1 comp, No T-VIS, stronger internals,USDM use MAF, 235cc injectors
4AG 20V 4th gen "Silver Top" - Switched inlet cam timing, 3x inlet valves per cylinder, sequential injection, 10.5:1 comp, ITB intake, vane MAF, distributor ignition, 295cc injectors
4AG 20V 5th gen "Black Top" - Switched inlet cam timing, 3x inlet valves per cylinder, sequential injection, 11.0:1 comp, ITB intake, MAP sensor,
4AGZE Big Port - ECU controlled clutched supercharger, batch fired injection, waste spark ignition, 365cc injectors, MAF.
4AGZE Small Port - As above, MAP sensor
Sensor Information
Distributor
Description
There are a number of distributors found on 4AG engines.
Variants include:
1. 24x with 4x up the top
2. 4x with 1x up the top
3. 24x with 1x up the top
4. 24x with 1x up the top cam sensor (4AGZE)
There has been a variant sited as having just 4x down the bottom, but this is more likely from a 4A and not a 4AG.
Variant 1 can be used but requires 3 of the 4 teeth cut off so the distributor is left with 24x and 1x
Variant 2 is supported and configured as a Generic Standard Full Cycle Sync
Variants 3 and 4 are supported and configured as the Toyota 4AG trigger type
DISTRIBUTOR WIRING
All models use Reluctor sensors
4AGE Big Port (24x + 4x after modification)
| OEM Wire Colour | Signal Name | Description | Haltech Wiring |
| Red (24x) | NE + | 24x signal positive | Trigger + |
| White (24x) | NE - | 24x signal negative | Trigger - |
| Red (1x) | G+ | 1x signal positive | Home + |
| White (1x) | G- | 1x signal negative | Home - |
4AG 20V
| OEM Wire Colour | Signal Name | Description | Haltech Wiring |
| Pin D - Black | NE | 24x signal | Trigger + |
| Pin C - Red | G1 | 1x signal | Home + |
| Pin B - Green | G2 | 1x signal + 360deg | No connection |
| Pin A - White | G- | Signal Ground | Signal Ground |
4AGZE
| OEM Wire Colour | Signal Name | Description | Haltech Wiring |
| Red | NE | 24x signal | Trigger + |
| Green | G1 | 1x signal | Home + |
| Yellow | G2 | 1x signal + 360deg | No connection |
| White | G- | Signal Ground | Signal Ground |
Trigger/Home Wiring Hack
For applications where there is a dual Hall Effect pickup in a CAS or Distributor there is a quick wiring hack that allows the Home+ signal to be incorporated in the Trigger 4-core shielded cable. This can make the wiring much cleaner and easier.
To do this we will be relocated the wiring at the ECU Connector so that the unused Trigger- wire is instead placed onto the ECU pin for Home+. This means that the Trigger 4-core cable now has 12V+, Ground, Trigger+ and Home+ all in the one cable. The GREEN wire that is labelled at Trigger- is now actually the Home+.
For Elite 550/750/950 models
1. Unplug the Main Connector at the ECU end.
2. Unlock the connector by pushing in the large white tab on the connector until it clicks. This will cause the two smaller white tabs to pop up on the other side.
3. Remove the Yellow Home+ wire from pin 32. Insulate this wire, it will not be used.
4. Remove the Green Trigger- wire from pin 33 and move it to pin 32. Push it all the way until you can see the metal pin clearly from the pin side of the connector and it looks the same as all other pins.
5. Lock the connector by pushing back down the 2x white tabs until they click into position.
For Elite 1000/1500/2000/2500 models
1. Unplug the smaller 26-pin Main Connector at the ECU end.
2. Unlock the connector by pushing in the large white tab on the connector until it clicks. This will cause the two smaller white tabs to pop up on the other side.
3. Remove the Yellow Home+ wire from pin 2.
4. Remove the Green Trigger- wire that is in pin 5 and move it to pin2. Push it all the way until you can see the metal pin clearly from the pin side of the connector and it looks the same as all other pins.
5. Lock the 26-pin connector by pushing back down the 2x white tabs until they click into position.
Common 4AG Trigger Issues
It is a common issue to see 4AG Reluctor trigger systems to be biased towards the negative side of 0V, usually crossing at -0.25V.
To ensure correct operation it is often necessary to use a customer trigger configuration as below.
Trigger Configuration
Ignition Coil and Igniter Module
For all models the body of the igniter must be grounded to the chassis.
16V Distributor Models
These models have an old old-filled tube coil design with an external igniter mounted to the side of the coil
AE82 Wiring
| Wire Colour | Function | Haltech Connection |
| Black/Yellow | IGF (Fail Signal) | --- |
| Black/Blue | IGT Signal From ECU | Ignition Output 1 (Yellow/Black) |
| Black/Orange | 12V+ Switched | --- |
| Black | Tacho Signal | --- |
| Black | Coil -ve | --- |
AE92 Wiring
| Pin | Function | Haltech Connection |
| 1 | IGF (Fail Signal) | --- |
| 2 | IGT Signal From ECU | Ignition Output 1 (Yellow/Black) |
| 3 | 12V+ Switched | --- |
| 4 | Tacho Signal | --- |
| 5 | Coil -ve | --- |
20V Distributor Models
These use a newer style coil with a higher output and an external separate igniter module.
Pin | Function | Haltech Connection |
E | IGF (Fail Signal) | --- |
D | Signal From ECU | Ignition Output 1 (Yellow/Black) |
C | 12V+ Switched | --- |
B | Tacho Signal | --- |
A | Coil -ve | --- |
4AGZE Waste Spark Model
Wire | Function | Haltech Connection |
Brown | 12V+ Switched | --- |
Grey | IGF | --- |
Pink | IGT Signal from ECU 1 | Haltech Ignition Output 1 (Yellow/Black) |
Yellow | Tacho Signal | --- |
--- | --- | |
White | IGD Signal from ECU 2 | Haltech Ignition Output 2 (Yellow/Red) |
2-pin Connector
Wire | Function | Haltech Connection |
Light Blue | Coil -ve 1+4 | --- |
Black | Coil -ve 2+3 | --- |
Throttle Position Sensor
| Pin | Description |
| 1 | 5V+ |
| 2 | Signal |
| 3 | Idle Switch - Not Used |
| 4 | Signal Ground |
MAP Sensor
AE92 MAP
| Pin | Description |
| 1 - Brown | Signal Ground |
| 2 - Yellow | Signal |
| 3 - Light Green/Red | 5V+ |
Calibration: Use "xxxxxxxx.cal"
Idle Valve
4AG20V
The 4AG 20V engine uses a dual-solenoid system. This uses 2x ECU outputs and a 12V+ power supply. One signal opens the valve, the other closes it.
It is configured in the software as a BAC 3-wire
| Pin | Function | Haltech Connection |
| 1 | Open Signal | Spare Output |
| 2 | Power | 12V+ Switched |
| 3 | Close Signal | Spare Output |
Coolant Temperature Sensor
Located on the rear of the engine above the gearbox bellhousing.
4AG20V Coolant Temp Sensor
Wiring is not polarity sensitive
Calibration: Use "Temperature - Toyota 1FZ-FE Coolant Sensor.cal"
Created for Haltech ECUs using a 1k pullup to 5V
Air Temperature Sensor
Wiring is not polarity sensitive.
Calibration: Use "Temperature - xxxxxx.cal"
Created for Haltech ECUs using a 1k pullup to 5V
OEM ECU Information
Models
Information about that model
<insert OEM ECU image>
<insert OEM wiring information image>
Base Maps
Coming soon...
Installation Pack
Downloadable zip file that has wiring information and base maps. Everything needed for someone to do an installation and startup.
Coming soon...
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