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theoretical MegaJolt Q.


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A while ago I started work on a Citroen Dyane6, slightly modernized 2CV.

After almost a year off the project and two days fruitlessly trying to get this bi¥h running properly and it barely starts and even then badly runs, anyone who knows these will know the distribution is a cow to set up and frankly, after 2 days infinately adjusting it and getting somewhere near nowhere, I'm sick of it.

New plugs, leads, points & condenser, coil and a lot of careful aligning of everything and marking of distribution box, and still no joy.

I just want it to run!

Is it even remotely possible to put MJ on a citroen flat twin?

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I don't think you can do it with a MegaJolt as it relies too heavily on EDIS to run the ignition. As far as I know the smallest EDIS controller is 4 cylinders and I'm not sure you could configure it for 2.

MegaSquirt wouldn't have a problem running it though using MS-Extra or MSII-Extra to fire the coil(s) directly. I know nothing about that particular engine but most flat twins seem to have both pistons at TDC at the same time so running a wasted spark system with a single coil should be easy enough. You could use one half of an EDIS type coil or one of the VW Jetta coils which have their own built in drivers. VW Part number 06A905104 has 4 coils, takes 12v ground and a 5v signal (I think it's 5v, could be 12 !) for each coil. You'd only need two coils in this case and would drive the coil directly from the MegaSquirt. Using the EDIS style coils is also possible but you'd need to build the MS with a coil driver which is not really a problem but not as neat as the VW coil. There are also some coil on/near plug units which have built in drivers (like the ones on the LS1) and have built in drivers, triggered from 5 volts. If the engine is "odd fire" and has the pistons offset so they don't reach TDC at the same time then you can fire them at different times.

All you need is a toothed wheel on the crank and a VR sensor, whatever you can fit as you're not limited to 36-1 although that's a good option if you can fit one. You don't need a cam sensor if you run wasted spark.

Also if you use MegaSquirt you could consider adding fuel injection at a later stage...

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Thanks, yes the Citroen does indeed run wssted spark system so options are good open there, I was primarily just looking at MJ as easiest and cheapest way of giving it electronic ignition.

Hmmm, an Efi 2CV :o might give me some horse power over the shetland pony power of srandard :D

will look for the VW coils and see what they come up like and then try and price it up, whole thing is on limited budget but this could be good for fits and giggles.

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Are you sure you haven't got other problems such as a carburettor fault or old/dirty petrol?

It is a long time since I worked on these, and yes, they are a bit different from a conventional set up because they have no distributor, just a points box which switches the double ended coil which fires both spark plugs at the same time.

Have you checked that the centrifugal advance mechanism behind the points box is not seized/sticky?

Have you used the static method of setting the timing using a 6mm diameter rod through the engine case into the flywheel timing hole?

Although a bit of a pain having to take the fan off to get at the points box, I always found setting the timing as per the manual worked fine for me.

Which is why I am wondering if you have a different underlying problem causing the poor starting/running.

I always found the engines utterly bulletproof and very well designed and engineered (albeit low powered). They can be ragged all day long and still capable of 60 to 70mph all day on the motorway (hills and noise/wind not withstanding!).

From memory the 2cv 602cc is 29 BHP and the Dyane 602cc is 31 BHP!

I would suggest that megajolt would be an waste of time and money unless you are planning to race it.

Good luck, hope you sort it.



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