gtir350 Posted July 29, 2017 Report Share Posted July 29, 2017 Hi All, hope someone is able to help me out.The project is a Nissan GTiR, Link LEM 3G. I wanted to switch to direct spark so got the followingcbr 600 coil-on plugsPlug that fit into the aboveMSD DIS 4 The car runs find under light load.The problem I am having is a misfire under load. What I have found is that the larger the dwell number the worse the misfire.I read that dwell had no effect when running CDI ?When running 0.5ms I get a small missfire over 5000RPM over 14PSIThe more I turn up the dwell upto 4ms the sooner ( Less load ) the misfire happensThe Spark time is 1msAnyone any any advise ?Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 29, 2017 Report Share Posted July 29, 2017 Make sure your "dwell edge" is set to falling. Set your whole dwell table to 1.0ms Quote Link to comment Share on other sites More sharing options...
gtir350 Posted July 30, 2017 Author Report Share Posted July 30, 2017 Thanks for the input ,I just set this to falling and all dwell to 1.0ms, but the engine will not start . Put is back to rising, at its start ok, but will will under load ( same as before - the higher the dwell the worse the miss )Everything Ive read says the MSD needs rising. Quote Link to comment Share on other sites More sharing options...
integrale8v Posted July 30, 2017 Report Share Posted July 30, 2017 When you are on the g2/g3 software/firmware the edge for ignition is opposite to the newer versions (g4 / g4+). That is why falling is correct on the g2/g3.It is "dwell edge" on the g2/g3 vs "Spark Edge" on g4/g4+ Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 30, 2017 Report Share Posted July 30, 2017 Thanks for the input ,I just set this to falling and all dwell to 1.0ms, but the engine will not start . Put is back to rising, at its start ok, but will will under load ( same as before - the higher the dwell the worse the miss )Everything Ive read says the MSD needs rising. it needs to be on falling. You will need to do base timing again as swapping edges will change timing. Quote Link to comment Share on other sites More sharing options...
gtir350 Posted July 30, 2017 Author Report Share Posted July 30, 2017 Thanks.I'll try this when I get back from work tomorrow Quote Link to comment Share on other sites More sharing options...
gtir350 Posted August 5, 2017 Author Report Share Posted August 5, 2017 (edited) Just trying this now,I've just done a timing calibration again and the difference when swapping from rising to falling is very small 2-5 degrees ( -120 -125 ) , Also hard to tell on the starter motor.Fixed at 10.Still just fires once then stalls when on falling.What am I missing ?** UPDATE **Just got this working, I needed to set the dwell to 2.5ms for the MSD DIS-4 unit..Tested by swapping to 1ms when running , and the engine stalls Edited August 5, 2017 by gtir350 Fixed Quote Link to comment Share on other sites More sharing options...
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