Janno Kusman
I'm software developer(Java) in [Tallinn/Estonia].
I own a [Nissan 200sx s13] with CA18DET engine(1.8T twincam 4cyl 16v) with lot of bolt-on mods. Currently it uses standard ECU that has been modified with EPROM emulator and custom maps in it. I'm also co-author of Nissan CA18DET chip editing software [1]
I want to help with adding/improving support for InputTrigger/NissanTrigger and testing it on my car. I hope to get help from Silver who owns Opel Kadett C with MegaSquirt 2 and who has also written some code for MegaSquirt 2 (we work in same company). Although Nissan standard ECU is programmable through EPROM emulator, it doesn't have support for wideband lambda and datalogging and also some functions are still unclear (ecu self learn function and ignition retard on detonation). It would also be fun to add some advance functions to VEMS as traction control, bang system and full throttle shift (cut ignition).
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 http://bagpuss.swan.ac.uk/horsham-developments/manuals/
Crank Angle Sensor (
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.
---
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.
http://www.route6.co.jp/products/ems/emstorisetu.htm 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.
http://www.hitman.hm/nissantrigger.htm is different, saying that trigger edge at 45 BTDC.
http://www.wolfems.com.au/products/enginemanagement/wolf3d/version4and4plus/version4installshortcut
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 http://www.autronic.com/page_files/trigger_disks.htm, but that costs ~$70 (USD)
---
Also info on InputTrigger/NissanTrigger: