Z31 Fuel Injector, ECU and O2 sensor and Interchange Information

ECCS Location

The ECCS or Computer for the Z31 is located behind the passenger's kick panel. This is the small panel on the outer wall right below the glovebox. You will need to remove 2 screws to get the panel off.

There are three connectors that plug into the ECCM. These connections can sometimes corrode and cause Driveability issues. Cleaning these will resolve some problems but sometimes for Diagnostic procedures you will need to check the pinout on sensors.

ECU Lookup

To lookup your ECU or interchange for ECU, O2 sensors, or Fuel Injectors, complete one of the search boxes and click submit. ECU can have a NMC number or a JECS number the numbers are listed as NMC/JECS these are interchangeable.

Non USDM ECUs

If your ECU is not listed you will have a Euro Or JDM ECU.

Below is a chart of these ECUs

If it has an alternate part number, that means the part interchanges between the two and vice versa.

These numbers are strictly pulled from the Euro and JDM FAST parts catalogs. It does not list the JECS number, only the Nissan part number.

ECU/Fuel Injector/O2 Sensor Interchange Information

There is absolutely no difference between a regular 1988 Turbo ECU and an “88SS” ECU. The “88 Shiro” branding is purely marketing and does not affect performance.

• NA injectors: ~180cc/min
• Turbo injectors: ~260cc/min
• ECUs are programmed accordingly.

High impedance ECU with low impedance injectors: You must install six 6–10Ω 10W dropping resistors to avoid damaging the injector drivers. If you add dropping resistors, the fuel injectors must be rewired to factory spec (pre-service campaign).

Low impedance ECU driving high impedance injectors: This setup should operate normally.

Feed type does not matter to the ECU. What matters are impedance and flow rating. However, the lower intake manifolds differ; you may need to shave or shim the injector mounting area if swapping between types.

Oxygen Sensors

• Titania and Zirconium sensors are not interchangeable.
• Zirconium sensors output a 0–1V signal.
• Titania sensors vary resistance for ECU feedback.

To use an 86–89T ECU with a different sensor type, you must rewire the harness and change the O2 sensor bung (Titania = 17mm, Zirconium = 22mm).

ECU Interchange Notes

• California and Federal ECUs: Fully interchangeable. CAL units include an EGT sensor.
• 88–89 ECUs: PROM chips are swappable between NA and Turbo models. This allows you to use a Zirconium sensor with an NA ECU by installing the Turbo PROM.
• Turbo ECUs: Feature a detonation sensor daughter-board (NA ECUs do not).
• Idle control: Turbo and NA use different systems, but cars can run fine with idle devices removed.

Additional Technical Notes

• 88–89 Turbo ECUs use a timing map optimized for the smaller T25 turbo at 4–5 PSI boost.
• 84–85 ECUs (all) may have a slight lean surge during cold start (first 30 seconds). Switching from CHTS to FTS during startup can fix this.

JDM Z31 ECU part numbers

EURO Z31 ECU part numbers

Europe had different emission standards for different countries at the time, hence the difference in part numbers for countries