Revision as of 23:59, 2 August 2017

Wiring for the Datsun A14/A15 EFI (EGI) system.

	Datsun Factory Fuel Injection

	EGI main article
	EGI Wiring
	EGI Photo Index
	A14E Service Manual
	Introduction of GX-E
	200SX EFI

1 Overview
2 Engine Harness
3 ECU Wiring
- 3.1 EFI Relay
4 Fuel Pump Wiring
- 4.1 Fuel Pump Relays
5 Injector Wiring
- 5.1 Dropping Resistor

Overview

Wiring here is based on Datsun S110 (Silvia/Gazelle/240RS), specifically the 1981 USA "200SX" version. See 200SX EFI.

The simplified "4-wire" setup, which assumes you are using a factory wiring harness cut out of a donor car, is:

IGN
START
GROUND/EARTH
FUEL PUMP

Engine Harness

Album 21852
Engine harness

Injectors
Air Regulator (air bypass system -- for idle speed)
EGR/VVT vacuum-cut switch (can be disconnected)
Throttle Sensor (Throttle position sensor)

ECU Wiring

22612-N7801 to 0681 (no O2)
22612-N8500 from 0781 (O2 sensor)

Wires from ECU to engine compartment
OUTPUTS
* Injector outputs (4)

Wires from engine compartment to passenger compartment
INPUTS
* Power (from EFI relay)
* coil negative (tach sense)
* air flow meter
* air temp sensor (in flow meter)
* throttle valve sensor
* START wire for ignition switch (to indicate when to do cold-start enrichment)
* water temp sensor (on underside of intake manifold)
* O2 sensor (not used on early B310)

EFI Relay

Needed: One relay, one Fusible Link, 20 gauge Power & Ground wires

There is a dedicated Fusible Link for the ECU
Album 26065

Album 21854
25230-C9900 RELAY ASSY [or 25230-C9907]
* SWITCH: 
  * C: BW wire from IGN switch
  * E: B ground/earth
* D SOURCE: from Brown fusible link to Light Green/white
* B OUTPUT: LgR to Red wire to ECU #207

200SX factory wiring diagram
Album click to view

B310 A14E wiring diagram
full | original

B310 ECU PIN
27 POWER
15 EARTH

Fuel Pump Wiring

Pump has 2 wires
* B: earth/ground
* LgR (Light Green with Red stripe): pump power

S110 uses 3 relays: FUEL PUMP RELAY 1, FUEL PUMP RELAY 2, FUEL PUMP RELAY 3. The multiple relays are for safety. Relay takes inputs from Alternator, ECU, and Oil pressure switch. Pump will shut off if engine dies, because Oil and Charge will stop working, the relays shut the pump off. This is important for safety in a crash.

Fuel Pump Relays

At the minumum to protect the wiring, you need one relay for the fuel pump. It draws over 5 amps, so you don't want to run it directly through the IGN switch at the risk of burning out the switch contacts or overloading the existing small IGN wiring.

Although you could use the minimum one relay, for safety the Datsun factory system uses a chained system of three relays.

Nissan 5-blade relay
* 25230-C9900/25230-C9907 RELAY-FUEL PUMP JIDECO 
* 25230-C9905 RELAY-FUEL PUMP NILES

Fuel Pump Relay 1

Pump On/Off: this relay engergizes the Fuel Pump and Air Regulator, but Relay 2 can open the circuit.

* SWITCH: 
  * C: (Lg) from Fuel Pump Relay 2 OUTPUT (Lg)
  * E: Earth/ground
* D SOURCE: BW from IGN switch
* B OUTPUT: LgR 
  * to Air Regulator LgR
  * to Fuel Pump LgR

Album 21854

Fuel Pump Relay 2

Pump Power: This relay is wired NORMALLY CONNECTED (i.e. when off). It passes on to Relay 1, but when Relay 3 is on it disconnects.

* SWITCH OFF: 
  * C: L from ACC L FUSE 15A
  * E: (switched ground) LW from Relay 3 OUTPUT (LW)
* D SOURCE: BW from IGN switch
* A OUTPUT NORMALLY CONNECTED: Lg to Relay 1 SWITCH(Lg)

Fuel Pump Relay 3

Pump Cutout: This disconnects the Pump Feed relay in certain scenarios.

* SWITCH: 
  * C: BW from IGN switch
  * E: WR to DIODE to Alternator WR
* D SOURCE: YW to GROUND/EARTH via Oil Pressure Switch
* B OUTPUT: LW to Relay 2 SWITCH (LW)

200SX Oil Pressure Switch is a dual-wire type because 200SX has an oil pressure gauge, but we only need the typical sensor used on all A-series engines. If you want to use a Oil Pressure Gauge, you can fit this sensor.

25070-80W0 DUAL OUPUT
* On/off pressure switch for OIL light & fuel pump relay
* Resistor sensor for gauge

Injector Wiring

How the injectors are wired depends on the ECU you use. The following is information on Nissan ECUs. If using Motec, Haltech, etc. see their instructions.

Here's the actual schematic for Dropping Resistor wiring from the 1978 A14E Service Manual. It shows a 5-pin resistor pack.
EGI Harness