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One of my current projects is '''Mitsubishi Eclipse 2L 16V turbo''' Engine 4G63 DOHC Year 1991 US version. Target is 350-400Hp using little bigger turbo from Evo3, forged internals, 70mm exhaust, injectors, fuel pump, intercooler.... As stock wiring harness is in good condition we use it and fabricate adapter loom from old Hyundai ECU PCB connector. ---- So I have two basic problems: trigger and stepper. Here is picture of '''optical sensor''': http://www.vems.hu/files/GintsK/Mits_trigger.jpg On outer trace is 4 evenly distributed holes. On inner trace a longer and a shorter pulse. Is it possible to use inner trace for camsync? Checkout ''' MembersPage/Fero/MitsubishiEVO , there is good chance the same setup for EVO6-7-8 works for this wheel too''' * of course the EVO6-7-8 crank-based primary trigger gives good precision and the old cam-based timing results in worse ignition precision but that's just the case where all signals come from belt-driven camshaft Another option is to use the plate manufactured by Rob? He's using it in Toyotas and Nissans, maybe compatible with this trigger as well. I will check it. Curently we make plate which imitate 12-1 crank sensor an 1 cam pulse. Will see. ---- '''4-winding unipolar idle stepper''': http://www.vems.hu/files/GintsK/stepper1.jpg Looks like a unipolar stepper. The ECU needs to control 4 signals, pull to ground. 2nd and 5th pins are 12V from main relay. Connected somewhere deep in loom. I got stepper working in terms of opening/closing from keyboard mdi command. A: '''But it becomes hot''' because while the stepper chip pulls down one pin, the other flies to 28V (2xVBATT) which interferes with the flyback inside the stepper. Really because of flyback energy? Stepper becomes hot at rest situation when no commands from ECU. My engine not running yet. A: * use series diodes on the outputs (total 4 needed) ** the 1n4007 diode in the rescue kit should be fine A: * you can also "unpower stepper except when moving" ** it's a bit in iac_conf : prolly makes little differnce after you add the 4 diodes That is what I want. i think all four outputs must switched to 12V when no moving. How can I configure it? Is it reachable from Megatune? A: * yes, reachable from megatune * all 4 outputs seem to go low (not to +12V) when iac is unpowered (this is not enough to prevent heat, unless you connect the stepper common pin(s) to ground, NOT +12V) * but the stepper enable signal is also pulled low. This should disable the stepper outputs IIRC (check the SN754410NE datasheet to be sure) <code> if (config.iac_conf & _BV(power_off_iac)) { S259(DLOW, S259_STEP_EN); S259(DLOW, S259_STEP_A); S259(DLOW, S259_STEP_B); S259(DLOW, S259_STEP_C); S259(DLOW, S259_STEP_D); </code> * this code means unpower feature switches ABCD to ground, but the stepper_enable signal is also pulled to GND, disabling any current from stepper outputs * unpower feature is almost never used, since the 130mA current (stepper winding is appr 100 Ohm) is cheap, worths the extra safety that the stepper position is maintain firmly (prevent stepper drift) ** you're suggesting we should set the stepper outputs to high (+12V) instead of ground ? As the stepper_enable signal is also pulled to GND, theoretically it disables any current from stepper outputs: why don't you try it ? (together with the 4 diodes) * Yes i had idea connect supply pins of stepper to ground. But problem is we use unmodified OE wiring and adapter loom to OE ECU connector. Stepper supply is connected somewhere in loom together with main supply. I prefer leave it as is.
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