Editing Z31/ECUdifferences php (section)

=== 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.

![https://dev.z31library.com/xenonzcar_archive/z31/images/Fuel%20Injectors/TopFeed.jpg Top Feed Fuel Injectors]

![https://dev.z31library.com/xenonzcar_archive/z31/images/Fuel%20Injectors/SideFeed.jpg Side Feed Fuel Injectors]

'''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
[[Z31/droppingresistors|dropping resistors]]
to avoid damaging the injector drivers. If you add dropping resistors, the fuel injectors must be
[[Z31/Rewirefuelinjectors php|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.