M30 wasted spark - won't start, backfires hard after cranking

[l0gistaja]

Hello. So I'm currently in the middle of building a turbo M30 and I've hit a bit of a bump. I'm running kdFi v1.4 (MS2) and decided to upgrade to wasted spark ignition (part no. 1208007 - Opel V6 coil hooked up to the integrated power drivers on the kdFi). After getting everything wired up and switching to wasted spark in Tunerstudio I went to try and crank it and the engine struggles to start now. Sounds like it's just about to start but won't. After I stop cranking, there's a huge bang from the exhaust - even broke a plastic box I had behind the car. Could this be because of a small dwell time or could it be something else? I haven't gone over 3.0 dwell yet, will try higher when I get back home.

[e30davie]

Sounds to me like you either have your cylinders wired wrong, or the ECU outputs dont match what the software thinks the are wire to. And you are hugely out of time - resulting in the big bang

I have wastted spark on ms2 as well, I have mine paired 1-6, 5-2,3-4. and wired to the A/B/C front LED outputs in that order. as i understand the ecu is hardwired to fire them in that order A-B-C-A-B-C etc, which you cant change. but i am not familiar with the KDfi or whatever. is it just an MS2?

Need to make sure you have it wired up correctly (paired correctly to the correct outputs and the ecu knows what cylinder is connected to what output).

Then if you think you have it correct, set it to zero timing, and put a timing light on cylinder 1 and see how out you are against the marks on the harmonic balancer.

Assuming you also have your 60-2 teeth setup with the correct offset?

I would not go increasing the dwell just yet. 3ms is loads of dwell for starting and idling. you want to run the least dwell you can get away with.

[l0gistaja]

Thanks for a quick answer. I think I have everything wired up correctly. A to 1-6, B to 5-2 and C to 3-4. I do have the 60-2 setup and the first tooth is set to 84deg. Gonna try and mock up a timing light and check the marks.
Edit: Checked sparks with a spare plug I had laying around and noticed that the spark was a bit weak. Increasing the dwell time helped with that but now the car won't even try to start. Not even a hickup. Checked the plugs on the car, they were wet but worked fine once dried.

[14thirty]

Use the test mode in megasquirt to confirm the correct plugs are sparking. I found the numbers on my bosch coil pack didn't correspond to the lead numbers.

[l0gistaja]

Thanks for the great tip, I didnt even know test mode existed. The numbers were indeed wrong but even after correcting them, it still just cranks without even the slightest sign of trying to start. Feels as if there was no spark when the plugs are on the engine.

Edit: Played around with the first tooth position in triggerwheel settings and it tries to start now. Gonna tinker with it a bit more and will report back with the results.

Edit 2: Feels like a fuel issue now. I kept my eye on the AFR gauge and it didnt change even the slightest when cranking. Could anyone share their injector characteristics and other injector related settings please? I currently have stock injectors on but when I get it to fire, I'll swap in some 360cc ones.

[l0gistaja]

Okay so I messed up the req fuel constants when changing the injectors back to stock and had forgotten to add a zero. Engine displacement was 300cc instead of 3000 resulting in not enough fuel. Changed that value and she fired right up. It was a pretty novice mistake but I have learned a lot during this tinkering with MS. Thank you for all the help.

[l0gistaja]

Looks like I spoke too soon. Everything was running well, I had some lunch and when I came back the engine would no longer start. Back to just cranking again.

Edit: Waited a day and when I tried to crank again, the engine fired right up. Didn't run on all cylinders at first but after a few minutes of running everything was good. Looks like this problem is solved now.