The following resources have been obtained while installing VEMS on Toyota 4A-GE 16V & 20V engines.
VehicleFitment/Toyota/Injectors
VehicleFitment/Toyota/Triggers
VehicleFitment/Toyota/IdleAirController
After the previous work using pull-down resistors we moved onto the suggested 10k->12V pull-up resistors and the addition of a 220nF cap on top of C40.
Still not good, the latest trigger log shows some strange missing tooth issues:
http://vems.hu/www.vems.co.uk/VEMSTrigger/4AGETrigger3.txt
Action to try next:
- Try to match the OEM pull-up of 0.6V with smaller value resitors.
- Try pull-down resistors as before, but with LM1815 pin5 jumpered to cause LM1815 to ignore any voltage below 200-450mV
- Use a seperate ground feed direct to the LM1815 chip.
Toyota 24+4 Trace:
Recorded with USB Instruments Stingray
- Testing on the bench with: Recorded trigger as a wav works okay, testing distributor driven by a motor works fine.
- Testing with the trigger in the car through the loom does not give an RPM reading.
- so the amplitude is too small, or the pullup too strong
- DC voltage measurement ?
- AC voltage measurement ?
- RPM ? Cranking ? or somehow running engine (with alien ECU) ?
Config & Tables
http://vems.hu/www.vems.co.uk/VEMSTrigger/config.txt
http://vems.hu/www.vems.co.uk/VEMSTrigger/tables.txt
Connection Details
The Ne (24tooth) trigger is connected to Trig1, the G1 (4 tooth) trigger is connected to Trig2. The G- combined ground connects to the common grounds. Two 270Ohm resistors pull the signal down to ground.
Trigger Logs
Initial test:
http://vems.hu/www.vems.co.uk/VEMSTrigger/24+4InCarTrig.txt
Test with the Ne and G1 trigger inputs changed over Ge to primary trigger, Ne to secondary trigger - we were out of clues so we thought we'd try it...
http://vems.hu/www.vems.co.uk/VEMSTrigger/24+4AfterSwapTrig.txt
Changing back to the correct trigger connections but removing the pull-down resistors.
http://vems.hu/www.vems.co.uk/VEMSTrigger/24+4FinalMiseryTrig.txt
A log from the bench test
http://vems.hu/www.vems.co.uk/VEMSTrigger/24+4BenchLog.txt
The owner of the car has produced a spreadsheet to try and analyse the trigger logs:
http://vems.hu/www.vems.co.uk/VEMSTrigger/24+4waveformsgraphed.xls
Toyota 24+4 Distributor:
#10 is the injector signal - indicating 1 injection event every two ignition events.
Divider=02 means injection event every second ignition event. Good if you have 2 injectors hardwired in parallel. (or, even than, you can (at the cost of a few wasted cycles) do something like: h[0]=00 02 00 01 .. .. .. ..