4A-GE Trigger

The connector is described at 4A-GEPinOut

These have a potential market for Corolla (AE86 and newer) and MR2. These engines are used in Mk1&Mk2 Ford Escorts as they are very similar to the Cosworth BDA engine, powerful and light.

Some decent scope traces.

http://www.jamesmccombe.com/tube/Cars/MR2/ImageLibrary/Thumbnails/Drivetrain/EngineManagement/DistributorTesting/ContactSheet.shtml

Information on the Toyota 4a-eg timing system - distributor driven.

http://www.autoshop101.com/forms/h23.pdf

Sensors

IAT Sensor

CLT Sensor

Timing

Here's a diagram of the type of trigger found in European and JDM Toyota 4A-EG engines.

In its simplest form we can use the G trigger and set VEMS as a Coil type ignition

Next step will be to modify the 24 tooth signal wheel to be 24-1, which will give us the ability to run fully sequential injection and coil on plug. The downside is that cranking may take longer (one rev!)

== Config - Coil type ==\n

# config using primary multitooth wheel only
# still using distributor based ignition, or wasted spark ignition
# depends on igchmax and h[2] table 
# CAMSYNC #####################################################################
cam_sync_f_edge_phase=FF
cam_sync_r_edge_phase=FF
reset_engphase_after=FF

## trigger and tooth wheel setup ###################################################
# tooth wheel, angular width of tooth
# For Toyota fitment we have a 24 tooth wheel revolving at 1/2 engine speed
# Two teeth must be ground 180degrees apart 360 / 12 = 30 (0x1E)
tooth_wheel_twidth1=1E

# tooth wheel, angular width of missing tooth
# 12 - 1 wheel, 2 times tooth_wheel_twidth1 = 60 degrees (0x3C)
tooth_wheel_twidth2=3C
tooth_wheel=0B  # 11 teeth between the missing tooth

# trigger1, bit0 0:falling/1:rising, bit1 0:toothwheel/1:coil, bit2 0:no filtering/1:filtering
# Toyota  G trigger:   primary_trigger=FE
primary_trigger=FE

# trigger2, bit0 0:falling/1:rising, bit1 0:toothwheel/1:coil, bit2 0:no filtering/1:filtering
#disable camsync use multitooth wheel on primairy trigger only
secondary_trigger=02

# tooth wheel, active trigger tooth
# after the missing tooth (00: right after missing tooth)
# so that trigger tooth is ~60 degrees BTDC
# Toyota with its 30 degree tooth width = 1
trigger_tooth=01

# The amount of degrees after the trigger till tdc
ign_tdcdelay=3C # 60 degrees

# you probably want 4 trigger event per cam rotation with the 2x 12-1 wheels you will have to trigger twice per
# crank rotation, that what another trigger tooth is for, trigger again after 6 teeth (180 crank rot)

another_trigger_tooth=6

crank_minper=50  # for std. coil tach signal

## Ignition setup
# crank advance = 10 degrees
ign_crank_advance=2E

# EDIS:0x0? dummy: 0x7? disable:0xff bit0: invertout
ign_out=70     

# i assume it is a 4 cyl ?
ignchmax=03

Config Notes

When setting up up timing keep mda28 fixed at 10 degrees

Adjust ign_tdc_delay until the timing is at 10 degrees during cranking as verified by a timing light.

Later Trigger types

Toyota have developed sensors for their later engines (such as found on MembersPage/DanielHenriksson page). These use either a single tooth G trigger:

Or a twin tooth G trigger: