MS3X Lt1 with LS1 coils, sync problems.

[Berry]

Hi, my first post, and my first build! Im using MS3X for controlling my 96 Lt1 engine using the optispark as a trigger, however i went with the LS coil packs (MSD 8245), all the other sensors on the engine are stock, ive wired two 330ohm resistors on the signal cables coming from the optispark to the 5v tps signal, first start on friday worked great, ran it for about 16 seconds then turned it of, after that it wouldnt start.
After some digging i found that the crank signal dissapears when i have the coils connected! if i remove the fuse for the coils i get at clean signal but as soon as the coils are connected the crank signal gets corrupted! (cam signal lookes fine)
I have the "high speed" ground from the coils wired directly to ground on the frame, ive tryed changing the cable for the high resolution from the optispark without any progress (shielded)
i can have the harness connected without connecting the coils and the signal is fine, it seemes that as soon as the coils start charging the cranksignal gets corrupted, tried mounting a capacitor on the power cables to the optispark sensor but that didnt change anything!

Im starting to get really frustrated with this! does anyone have an idea?

[Matt Cramer]

Can you make separate composite logs with and without the coils connected? These are special purpose logs for sync issues.

[Berry]

Well i cant right now! While waiting for this post to be approved, i removed the optispark from the engine (and the waterpump, drained the water, took off the crank pulley etc) and spun the optispark by hand while placing it on different lengths from the coils..
Had a signal every time i tried, started putting it together piece by piece, checking the signal each time a new part was mounted until eventually the whole engine was put together and working !? But im pretty shure its gonna fail again when i least expect it! But any ideas are appreciated!

[Berry]

Okey, the problem came back again! this time (same as last) ive been trying to get it running for a while and its been working but i have had troubles with backfiring for a while..
Im having two problems! one is that if i set it up as per the manual:

Typical settings:
Spark mode = Optispark
Trigger angle/offset = Start at 0 deg - adjust while strobing timing.
Ignition input capture = Falling edge
Number of coils = Single coil
Flip polarity on hi-res should be set to "Inverted"

i get sync error! if i use "rising edge" and Normal instead if inverted i get a signal! This time i tried altering the settings to the ones in the manual and after that my sync is lost with the coils connected (didnt set "single coil", just "falling edge" and "inverted") coils are MSD 8245 and now ive lost sync again!

ive made separate logs with the coils connected and not connected!
Any ideas?

[Berry]

think i figured out the problem! seems like the problem was my coils overdwelling! i noticed that when battery drained the signal came back! switching to fixed duty dwell made the signal appear again, im guessing the battery correction caused the coils to overdwell and disrupt the signal! but i still havent figured out why i get sync error if i set the trigger option "ignition input capture" to "falling edge" as described in the manual?

[Space387]

That is very strange. When I was running my LT1 on ms I used the manual settings and it worked perfectly but I was using the opti for a distributor also. 2 questions for you, first do you have a crank signal (4x) from the crank plus the high and low resolution from the cam, and if so are you using the crank sensor for a "low res" or are you using the opti presets and both the high res and low res signal? If not forgive me i cant remember if the 96 had them or not. Also I noticed you are running ls coils but it is set to single coil, is there an external coil driver?