BlownCorona Posted July 5, 2015 Share Posted July 5, 2015 hello electronically minded people. i am putting a megasquirt 1 into the corona to run ignition (still runs carbs) and am having trouble with inputs/outputs etc i am using the points as the trigger for RPM and then outputting to the coil via the coil driver mod. however i dont seem to be getting any input from the points to give an RPM signal. i see its meant to light up one of the LEDs when triggering but i get nothing. also when i bench tested it, the LEDs would like up a bit when powering on, but i get nothing now, im not sure if this is related to updating the firmware though. the ecu powers up and reads the few inputs i have fine (tps and voltage pretty much) so my real question is, does someone here who knows about this kinda stuff far better than i do, have any idea when i cant get a signal from the points, and thus no output to the coil for spark? i cant really find anywhere in tunerstudio that shows whats actually going on with the ecu hope that wasn't too confusing! cheers Quote Link to comment Share on other sites More sharing options...
Benno Posted July 5, 2015 Share Posted July 5, 2015 Never done any MS stuff so don't really know shit about specifics, but is the trigger expecting a high (+) or low (-) signal? I am guessing that it is expecting a positive voltage spike to signify the pulses, while your points (I'm assuming) are earthed so giving a negative voltage to signify the pulses. Do you have any form of voltage divider setup currently? Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 Is it in msns mode? If not itll be waiting for a sync pulse before anything happens. You need a pull up resistor from 12v to the ign input 1k is normal. Quote Link to comment Share on other sites More sharing options...
Benno Posted July 5, 2015 Share Posted July 5, 2015 Googled it and found this. Got a similar setup to this? Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 i did this from the diyautotune website, which should be the same as the diagram ben posted? its in MSnS mode too edit wrong copy past, hold up edit edit, typical, i cant bloody find the reference for the mod i did to run off of points, i certainly remember the 45 minute drive to find a jaycar to buy the 1k resistor thought! ill keep looking and post here to make sure ive done it right, but for now just assume there is a pullup circuit on the board now, Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 You must also have the input setup to optical / hall not vr. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 im suffieciently suspisious that i dont have this set up right, i cannot for the life of me find the instructions for the mod i did, but im pretty sure it was the same as this picture for a hall effect sensor. Do i ALSO need to put the 1k resistor from the battery up to the points? Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 You must also have the input setup to optical / hall not vr. under what section would i find this? i dont see it on the same pane as where i select MSnS Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 under what section would i find this? i dont see it on the same pane as where i select MSnS oh its not a software setting its how you setup the pcb. yes you'll need a 1k resistor from vcc to xg1(same as the above pic of the pull up from the battery). post a pic of what you have and ill let you know if its right. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 you can see the 1k resistor in place of D5, and the two jumpers as per that hall effect diagram. would this be the configuration for hall/optical you were refering too? and my issue is that i dont have the pullup resistor ciruit like i thought i did? excuse the silicone, trying to make sure nothing fails due to vibration URL=http://s1145.photobucket.com/user/71fliboi/media/IMAG0673.jpg.html][/url] Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 also for reference the Coil driver mod is tucked away underneath the board. hopefully there wont be any issues with that, once i sort out the tach signal Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 errr d5 and r10 need to come out and a 1k resistor inplace of d8 Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 oh right you are, D5, D8 and R10 were all removed, it seems i put the 1k resistor in the wrong spot. (is that hall sensor diagram the same for contact points?) so along with that, i should also run the lead+1k resistor from battery to the '+' side of the points for lack of a better term correct?? Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 then jumper from the right of the old d5 to xg1 this completes the cct from pin 24 to the opto coupler Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 Fix what you have first it will probably work without the other pull up resistor. If not then put a 1k resistor from vcc to xg1 Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 yup that link is there. seems i just put that resistor in the wrong spot for some dumb reason. sweet, looks like its nothing major then, will carry out these additions and report back! cheers! Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 5, 2015 Share Posted July 5, 2015 Yes hall and points are the same just a square wave. Reason we need the 1k pull up is so when they open and close to ground there is a voltage difference that the ecu can measure Quote Link to comment Share on other sites More sharing options...
h4nd Posted July 5, 2015 Share Posted July 5, 2015 Yes hall and points are the same just a square wave. Reason we need the 1k pull up is so when they open and close to ground there is a voltage difference that the ecu can measure Close, but not really. Let me show you a waveform from that point: You can see there's a bunch of edges even going negative, so you're going to need some signal cleaning to use that point, even if it's level triggered, though typically that kind of input is edge triggered... I assume the coil mood you mention will have that covered for you, thinking about it. Point to note, is that the peak voltages are ~100 - 200V Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 I moved the resistor to the correct location and now when cranking I had an led come on, unfortunately the battery ran flat after messing with it all day, so hopefully I can repair my charger tonight. Sorry for all the questions downtrail! But just to get my head around it, the 1k resistor mod IN the ecu, is this the 'pull up resistor' Or merely a configuration and the pull up is the external wiring in the pic Ben posted? Cheers! Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 5, 2015 Author Share Posted July 5, 2015 H4nd. the points are now sepreated from the coil, so voltages shouldnt be that high? Quote Link to comment Share on other sites More sharing options...
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