Nissan ECU description

Nissan Trigger (CAS)

The Nissan CAS is located on exhaust camshaft.

From Nissan 200sx s13 service manual. Manuals for s13/s14 are


Crank Angle Sensor with 360 pulses

The crank angle sensor is a basic component of the entire E.C.C.S (Nissan name for E.C.U). It monitors engine speed and piston position, and sends signal to E.C.U to control fuel injection, ignition timing and other functions.

The crank angle sensor has a rotor plate and wave-forming circuit. The rotor plate has 360 slits for 1 deg signal and 4 slits for 180 deg singal. LEDs and photo diodes are built in the wave-forming circuit.

When the rotor plate passes between the LED and the phot diode, the slits in the rotor plate cintinually cut the light being transmitted to the phot diode from the LED. This generates rough-shaped pulses which are converted into on-off pulse by the wave-forming circuit, which are sent to the ECU.

The 360 pulses is currently not supported. See InputTrigger/NissanTrigger . recommended solution is 24+1 or 12-1 or similar.

Let us know if you race in a special class where the pattern cannot be changed (eg. because engine must be unmodified, and be able to run with factory ECU also).

CAS pins are described on service manual pages EF-EC-83 and EF-EC-124.

A - Ground

B - 12v input

C - sync (1 deg sig) 5v output

D - trigger (180 deg sig) 5v outoput


CA18DET Direct Ignition System

Coil over spark


Ignition type is dummy, as ECU manages dwell(there are maps in standard ECU, that set dwell) and firing. has some intresting info on page 22. If individual

Nissan coils on plugs set Dwell to 1.75mS. Nissan set the position of this sensor to give the standard Nissan ECU a + Trigger edge at b 60 BTDC. Same document says that this is also true for Nissan SR20, RB20, VG30 and CA18 engines. is different, saying that trigger edge at 45 BTDC.

describes trigger/sync triggering.

Conclusion on InputTrigger/NissanTrigger

After reading some docs, I would say that Nissan uses trigger/sync triggering. Nissan trigger system is similar to multitooth/missing tooth system, but implementation is bit different - its other way around. Trigger signal goes high on TDC (actually 45 or 60 deg before TDC) and sync signal is generated for each crank degree. Trigger signal cylinder is determined by length of trigger signal (count sync signals - some Nissan triggers have different length trigger slot for each signal, but all have 1st cylinder longer than others).

NissanTrigger? input


Here is one picture of signal (cant remember, where I found it). Its probably for SR20 engine



It's also possible to modify input trigger with Autronic trigger disks, but that costs ~$70 (USD)


Also info on InputTrigger/NissanTrigger: