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VehicleFitment/Toyota (2015-01-01 07:00:00)

4A-EG Trigger

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

Some decent scope traces.

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

two ways I would do it

1) use is in 'coil type trigger' mode any only use the G signal. Apparently this is not enough even for wasted spark (just distributor).

OR

2) grind off one of the teeth on on the 24 tooth wheel and run 24-1 and only use Ne signal

3) use both signals as is (Ne as primary trigger, G as secondary trigger), and make some firmware modifications

[PhatBob] What sort of modifications? I still cannot see how we'd know where 'home' is without a missing tooth pulse.

Sounds like a simple setup:

This way we get a similar crank and crank-signal pulses to the processor as the HALL signal of the mazda-BP engine (eg. MembersPage/Fero ) has by default (without LM1815 of course).

Any info about the position of primary trigger falling edge ? If it's >50 crankdegrees BTDC, than it is supported without any firmware modification.

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

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

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

Toyota4AEGSignals.gif

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

For batch fire and wasted spark we can grind teeth from the Ne trigger.

The signals are generated from the distributor, which means that the 24 tooth wheel runs at 1/2 engine speed. Therefore we'll have to grind 2 teeth off the Ne trigger 180 degrees apart.

To make a fully sequential system we can grind three teeth from the G trigger.

Config - Coil type

Config - Batch type

  1. CAMSYNC #####################################################################
cam_sync_f_edge_phase=FF

cam_sync_r_edge_phase=FF

reset_engphase_after=FF

  1. trigger and tooth wheel setup ###################################################
  1. tooth wheel, angular width of tooth
  2. for a 60 tooth wheel this is 360 / 60 = 6 degrees
  3. For Toyota fitment we have a 24 tooth wheel revolving at 1/2 engine speed
  4. Two teeth must be ground 180degrees apart 360 / 12 = 30 (0x1E)
tooth_wheel_twidth1=1E
  1. tooth wheel, angular width of missing tooth
  2. 60 - 2 wheel, 3 times tooth_wheel_twidth1 = 18 degrees (0x12)
  3. 12 - 1 wheel, 1 times tooth_wheel_twidth1 = 30 degrees (0x1E)
tooth_wheel_twidth2=1E

tooth_wheel=0B # 11 teeth between the missing tooth

  1. trigger1, bit0 0:falling/1:rising, bit1 0:toothwheel/1:coil, bit2 0:no filtering/1:filtering
primary_trigger=01
  1. trigger2, bit0 0:falling/1:rising, bit1 0:toothwheel/1:coil, bit2 0:no filtering/1:filtering
secondary_trigger=FF
  1. tooth wheel, active trigger tooth
  2. after the missing tooth (00: right after missing tooth)
  3. so that trigger tooth is ~60 degrees BTDC
  4. Toyota with its 30 degree tooth width = 1
trigger_tooth=01

ign_tdcdelay=3C # 60 degrees

  1. trigger again at TDC (whuy?)
another_trigger_tooth=3

crank_minper=50 # for std. coil tach signal

  1. Ignition setup
  1. crank advance = 10 degrees
ign_crank_advance=2E

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

ignchmax=05

Config - Fully Seqential

[Insert config lines here]