Klmykvl Posted February 12, 2015 Share Posted February 12, 2015 Hey guys, My Megasquirt II quit working on me this week and I opened the case and could smell the burn. I noticed that R15 was burnt out so I replaced it and powered MS with the stim and R15 continued to get hot again so I disconnected. My question is: Could running my injectors without dropping resistors be the issue? the L28et came from a 1983 which I believe didn't have dropping resistors? Anyways I ordered a resistor pack from ebay because I figured it wouldn't hurt to install them anyways. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted February 12, 2015 Share Posted February 12, 2015 MS2 should not have any trouble directly driving low impedance injectors like the L28ET units. You may be turning them on too long before the PWM voltage reduction. How have you set them up? Quote Link to comment Share on other sites More sharing options...
Klmykvl Posted February 12, 2015 Author Share Posted February 12, 2015 from your response I think I may understand my error. Currently the injectors are wired to a 12v constant source. Could the constant power source relate to the burnt resistor? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted February 12, 2015 Share Posted February 12, 2015 (edited) With MS any injector is hard wired to +12, and to fire them MS grounds the other side. But the key to low impedance injectors is to apply full voltage to them until they open, about 1mS, then it turn the voltage off and on rapidly to hold them open for the rest of the injection event. If they are held on solid they will draw too much current and get hot. That current can also stress the injector drivers in the MS box. You can operate low impedance injectors with dropping resistors instead of the "peak and hold", but the turn on is not as crisp and you may have a harder time tuning at light loads like idling and low rpm cruising. By adding dropping resistors you can use the low impedance injectors like high impedance ones, just turn them on with full voltage for the whole injection event. Edited February 12, 2015 by SleeperZ Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted February 12, 2015 Share Posted February 12, 2015 Injectors should be wired to ignition. Quote Link to comment Share on other sites More sharing options...
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