GravityKnight

iTrader: (3)

I know for a fact, it adds quite a bit more dwell during cranking (over what the voltage/dwell tables call for). Does anyone know approx. how much more, and has anyone ever defined that part of the map so that it could be tweaked?

I have a very unique issue, well I thought it was unique until I found several others (other car types) with the same problem. I converted my setup to use D585 "truck" series LS2/7 coils. They put out an incredible spark.. no more misfires at/around peak torque! Car runs absolutely wonderful now... once it's running.

The car starts extremely badly (starter kickback due to firing way to early). These coils have over charge protection built in, if you charge them to long, they just dump (make spark). Turns out there are quite a few others that have had these issues after fitting these coils to their setup!

Many ecu's raise the dwell during cranking. They need around 4ms at 14v to fully "charge" and can take somewhere in the ballpark of 8-10ms before this auto discharge happens... which makes me nervous as to how much extra dwell the ECU is adding, because they can take even more dwell at lower voltages without overcharging of course (mine cranks around 10v with my small battery).

I was going to try running some very low dwell numbers at 11v and below, but I'm nervous it won't be enough and I'm getting concerned. I have the TB off waiting for shaft seals so I can't test again until tomorrow/the next day. I figured someone on here might know just how much dwell is added!?

GravityKnight

iTrader: (3)

I got the TB shaft seals today, so I put it back together and did some testing. The ECU must add quite a bit of dwell, I lowered the 11.4v and lower dwell settings down to .3ms and it still starts!, the issue I'm dealing with is improved, but still somewhat there.

Starting better, and with less kickbacks, but not 100% fixed. I played with the reduction factor tables as well to get these results. I also played with the comp2 table (the one shown as a percentage on my rom as I have the updated xml). Can't say for sure- but raising that percentage in those lower voltage - cranking - areas seemed to help.

The next thought on how to fix this issue, would be to find a way to lower the power the coils see during cranking with some resistors, but obviously not while it's running. I'll see how it does for a few drives and go from here.

ace33joe

iTrader: (2)

Interesting. I thought the only down side of too strong coils is shorter spark plug life.

Do you mind sharing more info / pics of the coil setup?

GravityKnight

iTrader: (3)

There is a shot of them, I welded mounting tabs on the strut bar at an angle. I guess that isn't the greatest picture, but it actually came out nice/even. I just used DSM NGK wires to work with them since they fit the plugs/head correctly. The coils are like $27ish a piece and they are very strong. But they are very temperamental to dwell time.


Well I managed to kill the starter

What sucks is that I just got my AEM v2 ems tonight. I got it to start once while the starter was on it's way out. Let it run for an hour or so while tuning idle/rev/stuff I could do without driving it. Once I shut it off, it won't crank.. starter just spins (bendix is gone I suppose). So I don't have the dwell problem anymore, but I don't have a starter either. Found an OEM new for $108 plus shipping, but it won't be here by the weekend.

Always something with this car...

ace33joe

iTrader: (2)

Oh wow much more custom setup than I thought.

Good luck with the starter and solving the problem.

I guess I will go Spoolinup COP or CDI when needed.