NicT Posted November 22, 2011 Share Posted November 22, 2011 Megasquirt is being interesting. Car is setup as follows, Cam 314/308, quads, headers, single transformer type coil with external ignitor (simple FET style with overcurrent protection) Alpha-N tuning with timing running from the 4 tooth wheel and the factory VR pickup in a 4age dizzy. Set the timing to fixed at 15 degrees in tuner studio to pull ign timing into line with what the ecu thinks it should be. Put the timing light on the crank and the mark is dancing around like a mad-man, anywhere from 25 degrees advanced to 5 degrees retarded. It was worse when running the internal ignitor and i was getting noise. Ideas on what it could be? Could coil dwell settings cause such bad ignition timing issues? Quote Link to comment Share on other sites More sharing options...
Yowzer Posted November 22, 2011 Share Posted November 22, 2011 Confirm you have your VR wires hooked up the right way around, or change the settings in megatune from rising to falling edge (or vice versa) and see if that makes a difference. By the sounds of it you may be triggering from the wrong edge. Quote Link to comment Share on other sites More sharing options...
NicT Posted November 22, 2011 Author Share Posted November 22, 2011 Going to get new leads and plugs tomorrow then attack it again. Have tried fiddling with those settings with no effect to result. However before tonight the car had a cracked coil and was missfiring. The missfire is better now but still terrible. Might be a compound of heaps of problems all at the same time. Will work from plugs back Quote Link to comment Share on other sites More sharing options...
barf Posted November 23, 2011 Share Posted November 23, 2011 is it MS1(eek) MS2 or MS3? are you triggering on leading or falling edge? i doubt dwell is the issue, simple things first; how free from noise are the VR signal(s) at the megasquirt-end of the loom? for the VR signal, i'd use twisted-pair at the least or preferably a fully shielded cable. you might need a 'scope, setting my VR zero-crossing (R56) and hysteresis (R52) on my jimstim helped but on the vehicle it could be different. i made a crappy youtube video a while ago, which might help - also, be sure you understand this document http://www.megamanual.com/ms2/vradjust.htm EDIT: could you drop your msq and a datalog here also? Quote Link to comment Share on other sites More sharing options...
kpr Posted November 23, 2011 Share Posted November 23, 2011 hes running a microsquirt (ms2) Quote Link to comment Share on other sites More sharing options...
Yowzer Posted November 23, 2011 Share Posted November 23, 2011 Confirmed it is plugged into the VR input and not the opto input? Quote Link to comment Share on other sites More sharing options...
keltik Posted November 23, 2011 Share Posted November 23, 2011 I seem to remember Keith Stewart telling me about a similar problem when was tuning my wagons link. In his case - it was to do with the software having an issue where you couldnt set the ignition timing within a certain range for some software reason or it would start jumping all over the show. He had to re-calibrate the triggers to an incorrect value so he could set the timing cells at like 60 degrees for idle to avoid the 10-30 degree range. So it was still actually firing at 15 degrees but the software didnt think so. Thats what i remember him saying anyways. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted November 23, 2011 Share Posted November 23, 2011 Slap the MSExtra code on it and rule the world. Quote Link to comment Share on other sites More sharing options...
sentra Posted November 23, 2011 Share Posted November 23, 2011 going to be the first dick to suggest removing/inspecting the vr/distributator + drive, (i dont believe it is that, it is only so you can say "oh davey, it is -definitely, definitely- not mechanical, because i inspected it myself and i am qualified to do so") Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 23, 2011 Share Posted November 23, 2011 What dizzy are you using? I remember CXG John having issues with the smallport ECU doing similar things on his G4 - switched to Bluetop style and it was fine. Quote Link to comment Share on other sites More sharing options...
NicT Posted November 23, 2011 Author Share Posted November 23, 2011 Slap the MSExtra code on it and rule the world. Did this first, capture is on rising edge, VR is wired into VR input one Distributor is bluetop running 4 tooth Tested distributor with drill and measured noise seems legit Did get a chance to get to car tonight had family shit. Tomorrow, need an oscilliscope first time in my life i could actually use one and an induction meter. Quote Link to comment Share on other sites More sharing options...
keltik Posted November 23, 2011 Share Posted November 23, 2011 Seriously dude, once youve checked everything else - try the timing thing i mentioned. Keith was telling me it drove him fucking nuts for aaaaages. Im fairly certain it was the same flavour megasquirt too. Had exactly the same problems you describe. Quote Link to comment Share on other sites More sharing options...
Testament Posted November 23, 2011 Share Posted November 23, 2011 play in the distributor drive? presuming you are setting the timing at idle, what is the idle speed? Quote Link to comment Share on other sites More sharing options...
NicT Posted November 23, 2011 Author Share Posted November 23, 2011 Car ran primo before with exact same dizzy and coil setup on factory bluetop, i have not modified or changed either, only thing i did was put a new o-ring on dizzy where it enters the head, thats it. I have a raft of measuring equipment i have borrowed from work that im going to test a few things on. Will start with new plugs and leads, then run up car and see what output timing from ecu is set to using automotive multimeter (which will tell me base timing and rpm based on pulses from ecu) this will show me if the ecu is infact outputting 15 degrees Then i will check static load on coil, resistance of coil, induction on coil, and set dwell according to these. Also reset timing belt tension and i retimed my cam last night as i was curious to see if that was out to what it was ment to be. It was fine. Ecu is a microsquirt so i have no pots to tune in VR as per these documents http://www.megamanual.com/ms2/vradjust.htm trying to see if theres something about this on microsquirt.info now. Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted November 23, 2011 Share Posted November 23, 2011 have you physically set the dizzi up to check where the rotor is pointing at tdc? if its too far advanced or retarded then the spark can jump to the wrong cylinder. dnt waste money on plugs and leads if they are fine. measure the resistance of the leads first, i doubt thats whats wrong. 3 ms dwell at 14 volts will work fine, more at cranking speeds/low voltage. get a g4 Quote Link to comment Share on other sites More sharing options...
NicT Posted November 23, 2011 Author Share Posted November 23, 2011 I set the dizzy as per instruction by toyota, engine TDC, timing marks on gear inline, fit dizzy. I even got a smashed cap, cut a hole in it and checked rotor position as it gets to tdc of ever cylinder. Leads and plugs cost nothing, and i already have them in my possesion. Next time i will get a g4 Quote Link to comment Share on other sites More sharing options...
sentra Posted November 23, 2011 Share Posted November 23, 2011 couldnt tell from your post if you did or diddnt end up getting a scope, /cme rnd if u need to borrow one Quote Link to comment Share on other sites More sharing options...
NicT Posted November 23, 2011 Author Share Posted November 23, 2011 couldnt tell from your post if you did or diddnt end up getting a scope,/cme rnd if u need to borrow one Nah i didnt get that, id buy one but im so very poor atm. Quote Link to comment Share on other sites More sharing options...
barf Posted November 24, 2011 Share Posted November 24, 2011 try using the tooth logger in TunerStudio -- it's pretty much a poor man's scope, albeit located after the ADC/VR conditioning circuit edit; i think using the 4-pronger is going to leave something to be desired in terms of resolution in the signal, which could lead to timing errors. the 24 tooth (Ne) signal was added to the newer dizzy's which as someone pointed out, might be a good solution offering you direct ignition also. Quote Link to comment Share on other sites More sharing options...
NicT Posted November 27, 2011 Author Share Posted November 27, 2011 This issue was fixed due to bad earthing. Quote Link to comment Share on other sites More sharing options...
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