Ignition and fuelling for an engine with no ECU

[Sam_C]

OK.....I need some help here from you clued-up gents! I have an engine from a winter project I'm messing around with which is complete but I have no ECU for it. It is from a specialist vehicle, which was produced in very small numbers in Italy. The company is long gone, and I don't have much information about the engine.

Apart from -it's an all aluminium 350cc two cylinder four stroke with multi-point fuel injection.
All the sensors appear to be there, I have the coil packs and the injectors are on the manifold.
The ignition pick-up appears to be a circular item on the end of the crank, no external trigger wheel visible.

Now , bearing in mind that I know the square root of FA about how all this electrickery engine management works, what would be my best course of action to get it running? I could replace the injection with a pair of motorcycle carbs, but I guess that I will have to run some sort of ECU for ignition at least, so it might be easier (all relative...!) to run spark and fuel from it.

So first question....is there a very basic ECU available that would be suitable? Would it even be possible to use an ECU from a similar configuration modern motorcycle or skidoo or something like that. (if they actually have them).

All suggestions welcome. I thank you

 

[jonbills]

I don't think you'll find an ecu you can just buy and plug in and it'll work.
But - Most aftermarket ecus I'm sure could control that engine, perhaps with a new crank sensor and other sensors changed or at least with all sensors, igniters and injectors understood. Oh and custom mapping.
So around £750 for the ecu, same again to sort the sensors and injectors etc and then same again to actually map it.
Or if your able to learn how they work, you could get a Speeduino or a Megaquirt and DIY for maybe £750 all in.

 

[Sam_C]

I don't think you'll find an ecu you can just buy and plug in and it'll work.
But - Most aftermarket ecus I'm sure could control that engine, perhaps with a new crank sensor and other sensors changed or at least with all sensors, igniters and injectors understood. Oh and custom mapping.
So around £750 for the ecu, same again to sort the sensors and injectors etc and then same again to actually map it.
Or if your able to learn how they work, you could get a Speeduino or a Megaquirt and DIY for maybe £750 all in.

Cheers Jon. I see you are building a Speeduino, that seems more of a sensible option than a couple of grand’s worth of kit for what is just a bit of fun. Couple of questions mate, bearing in mind my complete ignorance on this subject

Can you buy a “basic” pre-built Speeduino or are they DIY only?

Are there specific sensors for Speeduino or are they all basically the same, electrically speaking? Eg could I use my existing ones?
.
If I don’t know the timing data for the engine, would it be possible to set a “rough estimate” (say 7 btdc) that would at least get it started?

And on the same note...I have a crank sensor (not trigger wheel). I assume that the engine was running when removed. Is the purpose of the sensor to indicate tdc to the ecu (rather than firing point) which then determines spark timing? Or....

Sorry to tell you that you are now my “go to guy” for this, purely as nobody else has replied. Bit surprising really given the apparant interest in these systems on this forum.

cheers Sam

 

[jonbills]

Cheers Jon. I see you are building a Speeduino, that seems more of a sensible option than a couple of grand’s worth of kit for what is just a bit of fun. Couple of questions mate, bearing in mind my complete ignorance on this subject

Can you buy a “basic” pre-built Speeduino or are they DIY only?

Are there specific sensors for Speeduino or are they all basically the same, electrically speaking? Eg could I use my existing ones?
.
If I don’t know the timing data for the engine, would it be possible to set a “rough estimate” (say 7 btdc) that would at least get it started?

And on the same note...I have a crank sensor (not trigger wheel). I assume that the engine was running when removed. Is the purpose of the sensor to indicate tdc to the ecu (rather than firing point) which then determines spark timing? Or....

Sorry to tell you that you are now my “go to guy” for this, purely as nobody else has replied. Bit surprising really given the apparant interest in these systems on this forum.

cheers Sam

Yes, you can buy pre built Speeduino, this is the guy a bought my kit from
https://diy-efi.co.uk/product/speeduino_0-4-4_assembled although I'm sure there are cheaper on ebay etc.
It can work with lots of different sensors, but it wants sensors of the types it uses - it wants air temp, coolant temp, wideband o2, map, 3 wire throttle position sensor. It doesn't mind what brand of them, but it won't use a maf, won't use narrowband o2 well, won't use lots of other things.
In terms of crank sensor, it has quite a library of trigger patterns but it will need better than one signal per revolution. Best to have a look in the wiki and see what you can find
https://speeduino.com/wiki/index.php/Speeduino
Once you've got a decent crank signal, setting up an ignition curve is no problem. As you say, make a guess like 7 btdc at 500 rpm and take it from there.

 

[jonbills]

Here's the Speeduino crank signal decoder reference docs :
https://speeduino.com/wiki/index.php/Decoders

 

[Sam_C]

Here's the Speeduino crank signal decoder reference docs :
https://speeduino.com/wiki/index.php/Decoders

Sorry Jon, just seen this. Many thanks for posting. I've got the engine home now and started poking about with it and checking what it comes with, sensor-wise. Getting the engine running might be the least of my problems, given the amount of sensors, motors, solenoids and pipes sticking out of the auto flappy-paddle gearbox (and I don't have the electrics to control that either)

 

[jonbills]

I've seen a couple of threads on the speeduino forum for autobox controllers too, and I believe there are autobox controllers associated with megasquirt, so I reckon there are options.
Have you got some pics?

 

[Sam_C]

I've seen a couple of threads on the speeduino forum for autobox controllers too, and I believe there are autobox controllers associated with megasquirt, so I reckon there are options.
Have you got some pics?

I’ll get some and post them up, see what you think