Long story short I was having problems with Accel DFI 7 and old accel dual sync dist, had a few bad backfires and stall out 2x almost had to call AAA. I have a degree in electrical engineering technology(which I dont use) but in no way shape or form am I a professional electrical mastermind or programming coder etc. I said to myself Im going to make a 4 wire Holley dual sync work in place of this crappy Accel 6 wire dual sync distributor and thats just what I did over the past 2 days. Found Holley had blemished grade A 565-200 dual sync distributor on ebay for $200, also ordered a holley 10 pin ignition harness connector and 2 (3pin tps connector) to plug into Accel ignition harness they use for dual sync setup to so I didnt have to cut up any harnesses and make it ugly. My wiring had to look professional at the end of the day and I made an adapter harness for less than $10 that any good company would sell for $40+ but no one make it anyway lol. Its pretty simple when you compare the 2 wiring schematics, accel uses a ground, power and signal wire for each the cam and crank signals(6 total). Holly has 1 ground 1 power and a signal wire for cam and crank signal(4 total). Simple enough tie the 2 accel signal grounds to the 1 for Holley and the same for power(12V source). The ground wires comming from Accel dual sync are just for the shield grounds that cover the wires comming out of dist, and the holley unit doesnt have any of this garbage. I first tried to sync the distributor with Holleys intructions with both cam and crank led lights on and bam the thing ran shitty with the timing locked in at 26 deg, if I just unlocked it, it would backfire/pop at idle and shut off a few seconds later after stumbling etc. Called holley tech support this morning and they were clueless and of no help(1 hour wasted). So I proceeded to try Accels dual sync intructions for phasing the rotor which sets both leds off. It ran good with timing forced/locked, but once unlocked it would retard the timing way down to 10 deg(but not backfire) at 1400 rpms which I have commanded 30 deg in the dfi base ignition advance table. I figured maybe its gotta be the inductive/ignition delay time as the holley instructions say this need to be adjusted for advance or retarded after base timing is set and locked in, which I did at 25 deg. Went from 200 microseconds to 100 to 60 back up to 160, no change at all. I was heading somewhat in the right direction, but I would not be defeated by some new school vs. old school electronics BS. I did some research and stumbled on these install instructions for Accel DIS 8 that works with Accel dual sync. https://documents.holley.com/accel-d...stem_75610.pdf Both the aceel and holley dual sync say it has to be set on Falling for the crank trigger edge. Hmm thats interesting when these DIS 8 are setup and sync to have it Rising on crank trigger edge. Fkit I had to try it. In the system setup screen you need to change from DFI dual sync or hall effect eq. to CUSTOM and make the change from falling to rising trigger edge. Now its just not that simple. If you follow these instructions for rising edge crank trigger the sync of the leds is different. With both leds lit at TDC the cam light goes off when turning the dist housing CCW then continue to turn housing till the crank light goes off then comes back on again, stop and snug down the dizzy. Yea I was getting dizzy at this point and giving myself a headache. Cranked it up and set the base timing locked in, unlocked it and holy hemorrhoids its now advancing the timing just like it should and works like I always wanted it to 38 deg at about 2k rpms exactly what I have in the base advance timing table . No need to even adjust the ignition delay time I left it at the stock setting of 100 microseconds. This is a great sucess in my book and I hope someone else here can use this info. I would never call back Holley tech support to share this great discovery but I will share with this forum as it has helped me out many times. I searched all over the web and couldn't find anyone running this exact setup. If anyone is looking to do this, have no fear, Johnny is here!

 

Thanks for the info, it is helpful, nice to see you got it to work. I am a GEN 7 user as well.