Thumper Posted December 12, 2007 Share Posted December 12, 2007 I finished megasquirting my n/a l28. I'm running a 280zxt distributor, msd 6a, stock resistors, stock fuel rail and injectors. The car runs very good except light throttle and idle where the a/f ratios will jump back and forth and idle flucuates alittle bit. My gauges tell me my injector pulse will be 4.2 ms at idle then jump up to 5.2 then back to 4.2 I have made all my cells in my ve table around the idle the same percentage. The tach in megatune moves about 100rpms back and forth but the car doesn't feel like its missing that much. I don't have an aftermarket tach to verify and I haven't hooked up my stock tach yet. The only things I've come up with yet is a loose signal from the distributor (bad distributor, bad resistor, or bad power wire to distributor) or a grounding problem. I will be adding a few more grounds tonight in hope of seeing if this fixes it. Right now I have a ground from battery to starter bolt. Then I have all of ms and my sensors grounded on my intake manifold. So i'm going to add another ground inline of ms directly to the battery and add a ground from the battery to the frame tonight. Any other ideas? Thanks Also the voltage in megatune reads 13.6-13.8 which corresponds to what I get out of the alternator. Quote Link to comment Share on other sites More sharing options...
niner11 Posted December 12, 2007 Share Posted December 12, 2007 Just thought that I would add some info about hooking up the tach. I'm running an MSD6a with MSII pretty much like mobys write up with a few changes. Wound up getting a good signal for the stock tach by pulling it directly from the MSD box to the factory tach. Using the tach output on opposite side of box from power cable. Car is a late 74 Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 12, 2007 Author Share Posted December 12, 2007 Just thought that I would add some info about hooking up the tach. I'm running an MSD6a with MSII pretty much like mobys write up with a few changes. Wound up getting a good signal for the stock tach by pulling it directly from the MSD box to the factory tach. Using the tach output on opposite side of box from power cable. Car is a late 74 Thanks tried that and no go for some reason. I also did it on my 260z. But it doesn't seem to work on the 280z... But thats later first pulse jump. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted December 12, 2007 Share Posted December 12, 2007 Check a data log and see if you have your acceleration enrichment kicking in. Maybe your acceleration threshold settings are a bit too low? Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 13, 2007 Author Share Posted December 13, 2007 Check a data log and see if you have your acceleration enrichment kicking in. Maybe your acceleration threshold settings are a bit too low? I'm running map based acc enrichment and with a 10 kpa dead. So no dice their. Thanks though. BTW it does it all rpms and all loads. But not exactly the same jump in pulse. It jumps more at high rpms. And the grounds were not the problem. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 13, 2007 Author Share Posted December 13, 2007 Check a data log and see if you have your acceleration enrichment kicking in. Maybe your acceleration threshold settings are a bit too low? Ok give this man a cookie. So just to put my mind at ease I turned off map based accel and it went away. Put it back on map based and it came back. So I bumped up the dead spot to 20 from 10 kpa and it went away again. The weird thing is my map sensor was never reading anything more than 1-2 kpa difference no where near my 10kpa cutoff. But after looking at my datalogs I did indeed see the stupid accel kicking in. Well I now have a very good grounding system and a well tuned car so... Thanks Quote Link to comment Share on other sites More sharing options...
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