trwebb26 Posted August 14, 2006 Share Posted August 14, 2006 Has anybody ever had problems with megasquirt when it gets hot? My motor runs great when cold, but when it warms up - it starts to miss and eventually dies. I think my next step it to take the megasquirt apart and check for cold solder / bridges, etc. Any other suggestions? Quote Link to comment Share on other sites More sharing options...
sims76 Posted August 14, 2006 Share Posted August 14, 2006 Not enough information. Is it a misfire (rich or lean) or is it an ignition miss (like a few dropped ignition events)? Are you running fuel only or spark and fuel? Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 14, 2006 Author Share Posted August 14, 2006 Ignition Miss. I'm running the onboard coil driver through an MSD 6a (spark and fuel). Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 14, 2006 Share Posted August 14, 2006 We had an engine with an 8 pin HEI module that did not have heatsink compound on it. It would do exactly what you say, run great for a few minutes, then start to miss, miss more, then die. We suspected the module for quite a while, and then noticed when we removed it that it didn't have the grease to allow it to cool properly. Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 14, 2006 Author Share Posted August 14, 2006 Master Moby - so you are recommending that I take a look at the coil driver on the the megasquirt and address a way to cool it? One more note - I mounted my Megasquirt to the top of my tranny tunnel where the heat/ac used to be. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 14, 2006 Share Posted August 14, 2006 oh, so you are running v3.0 board. The easiest test is to take off the lid of the megasquirt case so you have access to the coil driver. Fire up and wait for the miss, then spray a little bit of freeze spray on the coil driver to cool it down and see if the miss goes away. That is an easy way to determine if the coil driver is overheating. Let us know what happens and then we can determine a better way to cool the driver. What coil and dwell settings are you running? Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 14, 2006 Author Share Posted August 14, 2006 I'm using the Red, Round Blaster 2 coil - 50% fixed dwell. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 14, 2006 Share Posted August 14, 2006 You have to set dwell control. Since you are using the v3 board and coil driver, it will not control dwell for you. The only time you can use a fixed setting like 50% or 75% is if you are driving an ignition module or box that will control dwell(like 4 pin HEI module or MSD box). Let us know if that helps. Try the settings I used on the TPI V8, it had a blaster coil. Go to the "spark" tab and the go to "dwell settings" select dwell control cranking dwell = 6 running dwell = 2.5 minimum discharge =1.5 Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 14, 2006 Author Share Posted August 14, 2006 Ignition Miss. I'm running the onboard coil driver through an MSD 6a (spark and fuel). ? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 14, 2006 Share Posted August 14, 2006 fair enough Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 15, 2006 Author Share Posted August 15, 2006 Holy crap do I think I've got it figured out... I had the board apart inspecting it for cold joints - and I thought I'd just check to make sure some of the components were in the right spot. Well... My board is wired like this: But I'm running an MSD - so I think it should be wired like this: So I guess my board is wired all screwed up (I ordered it pre-made from rs-autosport). To fix it - I guess I should: - Remove Q16. - Remove the jumper from IGBTOUT to IGN - Remove the 330 ohm resistor from R26 to (-)D14/wire lead & Remove the lead from (-)D14 to IGBTIN - Add a lead from (-)D14 to IGN. Does this sound right? What do I do with R43 & R57? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 15, 2006 Share Posted August 15, 2006 Does this sound right? What do I do with R43 & R57? Sounds correct. From looking at your diagrams I wouldn't do anything with R43 and R57 because they are in a part of the circuit that is no longer connected or used, so if they are in right now or out right now, just stay that way. Once you remove R26 and Q16 they no longer matter one way or the other. Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 15, 2006 Author Share Posted August 15, 2006 Great... Thanks for your help, Moby! Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 16, 2006 Author Share Posted August 16, 2006 Ok... I did what I said I was going to... and the car will barely start up. If I put my foot on the go-pedal it will run a little, but the timing is WAY off. It smells like unburnt gas pretty bad. Any suggestions, now? Quote Link to comment Share on other sites More sharing options...
Guest 1seymour Posted August 18, 2006 Share Posted August 18, 2006 make sure dwell and invert output setting is right for your setup in megatune. i think i saw someone posted that having the invert setting wrong made their timing off by 20 degrees. also, what's your trigger angle set to? Quote Link to comment Share on other sites More sharing options...
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