FJ20ET Engine

FJ20ET Engine

Information on the Nissan FJ20ET engine. The naturally aspirated FJ20E and FJ24 are not covered by this guide.






Haltech ECU Options

All Haltech Elite ECU models support this engine





General Information

Cylinders
4
Displacement
1990 cc
Firing Order
1,3,4,2




Model Variants

There are two variants of the FJ20ET engine.

Without Intercooler

8.0:1 compression

Turbo C With Intercooler

8.5:1 compression



Common Models

Fitted to the DR30 Skyline 2000RS Turbo and S12 Gazelle/Silvia RS-X.  It is more common to see the engine fitted to a different vehicle these days.  It was very common to fit them to Datsun 1600 (510) vehicles during the 1990's and 2000's.

DR30 has longer intake and twin scroll turbo manifold
S12 models have a shortened intake and log turbo manifold.






Sensor Information

Distributor

The distributor is located under the intake plenum. A dual optical (Hall Effect) trigger is used on this engine with a slotted disc inside the distributor.  The trigger has 4x slots spaced at 90 degrees with 1x slot larger than the others. The Home (sync) has 360x slots (1x every 2 degrees).  This trigger system does support Sequential fuel control and Direct Fire ignition.



Wiring
Wire Colour
Description
Haltech Connection 
Red
12V+ Switched
Red (Trigger 4-core)
Green
Trigger
Yellow (Trigger 4-core)
Black
Signal Ground
Blue (Trigger 4-core)
White
Home
Yellow (Home 4-core)

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 unusued 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.









Ignition Coil and Igniter

The ignition coil is an older oil-filled type and features an external igniter.  The igniter can be wired directly to the ECU.   They do not support high power levels.



  

Pin
Description
B
ECU Ignition Output
C
Coil -ve


It is common during a Haltech ECU installation to remove the OEM coil and module and move to something more modern.  An LS2 coil is a common choice due to their high output, internal igniter module for easier wiring, and common availability.


Dwell Time












Throttle Position Sensor

This engine uses a cable operated throttle body with sensor that only has a closed throttle switch.  This cannot be used with a Haltech ECU. The sensor must be swapped for another type that has a position sensor.







MAP Sensor

These engines do not come with a MAP sensor. 
Use the internal MAP sensor that comes with your ECU.  For higher boost levels an external MAP sensor should be used instead, connected to a spare AVI.








Idle Valve

This engine uses a 2-pin cold start valve which is of a switched type.









Coolant Temperature



Wiring is not polarity sensitive
Pin
Haltech Connection
1
Any Spare AVI*
2
Signal Ground
An AVI with a selectable Pullup should be used.  If not and external 1k pullup to 5V should be connected.







Air Temp

An Inlet Air Temperature Sensor is incorporated in the MAF Sensor on this engine.  See the MAF Sensor section for wiring information. If the MAF has been deleted a replacement Air Temperature Sensor should be installed in the inlet as close as possible to the vacuum source for the MAP sensor.  The Haltech HT-010206 is suitable for this.

Haltech HT-010206 Air Temperature Sensor


Wiring is not polarity sensitive.
Pin
Haltech Connection
1
Any Spare AVI*
2
Signal Ground
An AVI with a selectable Pullup should be used.  If not and external 1k pullup to 5V should be connected.







Knock Sensor

This engine comes with an older resonant style knock sensor.  These are known to be unreliable and can give misleading information on engines that are modified from standard. For accurate knock control a donut style non-resonant sensor should be used, such as the Haltech HT-011100.   

Haltech HT-011100 Knock Sensor








MAF Sensor

Although most users of Haltech ECUs will be deleting the MAF, it is possible to use a MAF if you prefer.




Pin
Description
Haltech Connection
1
---

2
---

3
5V+
5V+ (Orange)
4
---

5
Signal Ground
Signal Ground (Black/White)
6
MAF Signal
Spare AVI
7
Air Temperature Signal
Spare AVI (AVI-7 Grey) Pullup Enabled








O2 Sensors

This engine has a very old style single-wire Narrow Band O2 sensor.  Although it can be used for light load tuning for Lambda 1.0, they cannot be used for tuning under power.

For correct operation a Haltech WB1 kit is highly recommended for this application, with the provided 4.9 sensors replacing the pre-cat sensors.  Sensors use a 22mm socket or spanner to remove and replace.








Vehicle Speed Sensor

This engine receives a speed signal from the speedometer.









Injector Data

Flow

The injector flow rate is measured with the injectors held wide open at 100% duty.  For fuel systems with a fixed regulator pressure (often returnless systems) that is not referenced to manifold pressure the flow needs to be mapped over Manifold Pressure for accurate tuning.

Injector Flow:  370 cc/min


Dead Time

When an injector is commanded to open for a certain amount of time, the dead time is the amount of time the injector is not actually open during this period.  It covers the time to energise the solenoid and begin to open and the time to close as well.  There are also transient periods during which the injector is opening and closing where fuel flow is not at full capacity so this lost peak flow period is also taken into account.  










OEM ECU Information


   



ECU Pinout


 



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