letitsnow Posted May 10, 2012 Share Posted May 10, 2012 There's something weird going on, the base timing keeps changing on me. The dizzy is locked down and the sensor is bolted in tight. A few days ago I checked the timing because I thought I heard it pinging in boost, it was advanced, I adjusted the trigger angle to correct it. Today I checked again, it was retarded 8*, I adjusted the trigger angle again, 8* change, it moved 10, dialed it back a bit, no change, I set it back to the number I started with, but now the timing is correct. So the series of events went like this today: timing light reads 12*(20 commanded) change trigger angle from 329 to 321 timing light reads 23* trigger angle to 324 little/no visible change trigger angle to 329 timing light reads 20* MS2 v3 wasted spark DIYAT wheel in the turbo dizzy Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted May 10, 2012 Share Posted May 10, 2012 Are you looking at the actual spark advance in Tunerstudio, and not just looking at where it should be according to your table? I ask because there are ways to advance/retard timing based on IAT or CLT temperature or afterstart conditions. I'm not sure if it matters, but your trigger angle is high. Mine is set to 59.5, which is almost a whole revolution of the dizzy back from where yours is set. Granted you have a different trigger wheel than the stock one I am using. I've also heard of the damper/crank pulley slipping as the rubber ages, which can cause your timing marks to move, but I would think this would only be a problem under heavy load, not at idle as I presume these readings were taken at. Other than that stuff, the only things I can think of is either the whole distributor moving, which you said it is not, or the trigger wheel itself spinning, which is not likely because it has a D slot in the center. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted May 10, 2012 Author Share Posted May 10, 2012 (edited) I was going off the ignition advance gauge in TS. DIY says that's about what the trigger angle should be set to. I now believe it's slop in the dizzy drive. Edited May 10, 2012 by letitsnow Quote Link to comment Share on other sites More sharing options...
letitsnow Posted May 11, 2012 Author Share Posted May 11, 2012 Measuring it with a dial indicator, it works out to be about 2.5 degrees of movement. Not enough to cause the big discrepancy I saw. Quote Link to comment Share on other sites More sharing options...
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