The big thing to remember is that what is important is the tooth value spacing. Now, if you were running a 6 cylinider, like a 2JZ, the spacing on the teeth values will change because you still have 24 teeth per cycle but 6 cylinders, so 24/6=4 and your values would be 0,4,8,12,16,20. Using coils 1 & 2, you tooth values would be 0 & 3. and then set your firing order but you lose the independent cyl ignition trims.įor 1UZ's that still have the stock distributors (like my '91 SC400) You'll need to change "Spark Teeth" from 24 to 6 so that it will fire one output every 180 crank degrees. Alternatively, you could change the option "Spark Teeth" from 24 to 12 and leave coils 6-10 off. On the 2nd gen boxes have 8 coil outputs but still have the aliasing but have them as Coil 1 & Coil 1B which makes things a bit easier. It is done this way so that the ECU can trim timing for each cylinder independantly even if they are on the same coil output. Coils 6-10 are aliases of coils 1-5 so when the tooth count for Coil 1 or Coil 6 comes up it will fire the coil 1 output, 2 & 7 will fire coil 2 output, etc. On the first gen ECU's there are physically only 5 coil outputs but there are 10 outputs in the software. Ignition is the same way with one little trick to it. (you also must check box the "Eng Cycle = 1 Rev" so the ECU know that 12 teeth is one engine rotation and not one engine cycle. You'd then use 0,3,6 & 9 for your fuel teeth and setup your firing order. On the eariler 1UZ's that are batch injection off four injector outputs (like my '91 SC400) you must change the option "Fuel Teeth" from 24 to 12 to tell the ECU to restart the injector count every 12 crank teeth or one engine rotation. If you wired the injectors in the firing order inj 1 to cyl 1, inj 2 to cyl 8, etc. So, if you follow the count, you get 1-8-4-3-6-7-2. So for sequential injectors wired per cyl number you'd have: (for later model engines with the 36-2 crank wheel, the EMS only counts the 12 teeth that are even spaced so you still have 24 per cycle) For V8 sequential, the fuel and ign teeth should be space out every 24/8=3 teeth. These are also in "teeth" with smaller values meaning more advance and larger values meaning more retard,įor example, the 1UZ has 24 crank teeth so 24 teeth is one cycle. The option "Ignition Sync" and Injector Phase" options adjust overall base timing in relation to TDC #1 firing. The way it works is that the ECU just keeps count of the crank teeth and fires the inj/coil when it gets to the output's tooth value set in the inj/ign phasing options. Same thing goes for ignition although in a wastedspark setup, the coils that are 360 crank degrees apart must be wired to the same output. On AEM ECU's, the injectors can be wired to the injector outputs in any order you want as the firing order is fully configurable in software. I'm writing this to help out guys that are doing COP and sequential injector conversions with AEM ECU's.