Sleepy boxes (Ducati ignition modules)

Hi Bill. I think you said it all. :)

I think you said it better than I could. LOL

Shelley, Just try the ice trick and let us know how it went. Don't bother doing anything else until you try it.

This is a common problem with the ignition modules. I've had 3 faulty modules myself. Your options are:

1. buy new Rotax modules.
2. buy new modules from Mark Kyle in Australia who manufactures an uprated version.
3. send them to Carmo Electronics in the Netherlands for repair.
4. buy a new pair of a different design from IgniTech.

The circuit is designed in such a way that the amplittude of the inductive pick-up pulses controls the 2 ignition timing settings. Ageing of the threshold control components can give rise to the cranking speed being insufficient to generate a large enough pulse amplitude to trigger the ignition. Sometimes applying some heat to the modules can lower the trigger threshold and this also allows the circuit to operate. This only seems to be a starting issue, once the engine is running it keeps going.

There is another common fault that means that the kill circuit doesn't work and the only way to stop the engine is to turn off the fuel!

Correct, if you do not connect the ASM wire to the start-relay, no harm is done to the module and the ignition functions exactly like a non-ASM module (no soft-start)

Note that the ASM flywheel fires at 3 degrees After top dead center, so the piston is has already gone past top dead center and is traveling away from the combustion chamber when the spark plug fires.

Thanks guys for all your replies. Much appreciated. I’ll definitely be trying the packing with ice trick.

Shelley 

Thank you so much for everyone’s comments and knowledge. I’ve learnt loads and been doing a bit more research into the modules..,

I have read a few times now that the modules have a START mode and a RUN mode which operate quite independently of each other, is this correct? I wonder if that is referring to the timing in terms of the soft start timing and normal operating timing? 

When modules begin showing more frequent tendencies to enter hibernation mode (probably as discussed only realised by the pilot when both modules decide to hibernate at the same time meaning the engine won’t start) can this fault transfer to the RUN mode of the modules and potentially cause intermittent, or complete ignition failures during flight?

The chap who had the non-starting 912 with two sleepy modules decided in the end to buy two brand new modules for peace of mind as he was worried about in flight failures. However you guys have kind of suggested the hibernation fault with the capacitors generally only affects the engine start phase and that it’s likely the module will re-energise itself when paired with a working module and cause no further problems until the next engine start.

I’m just curious because when I ran his modules one at a time on our aircraft one module refused to come back to life 90 percent of the time after a decent run time but every so often it would wake up and start working again. 

The other module woke up quite quickly after starting with a working module and ran perfectly for ages on its own. After assuming that module was now fine I just happened to start the engine a second time and a minute or so into the engine run it started dropping out which surprised me and made me question if it was to be trusted in flight.

Whenever I have run up sleepy modules before they have always worked normally (as far as I could tell) from that point on but these two seemed to be acting differently showing intermittent running faults.

It’s one thing the modules failing to start the engine but a very different thing when they stop the engine during flight! 

All the intermittent module issues I have had experience with during engine running have always been due to broken wires and have been traceable such as the power feed wire from the generator, or poor connections to the ignition coils. 

Can failing capacitors at engine start also give rise to intermittent or complete ignition failures during engine running or would normal operation failures be indicative of other hidden issues?

Thanks

Shelley