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[Rattlebattle]

Thanks for that Thack; very informative. Proper analysis beats uninformed opinion hands down. It seems that the EFI system is not as basic as first thought. I thought that the injection timing had to have something to do with the MAP sensor because none of the others is relevant. Thanks once again.

[PeteF]

Am I the only one who doesn't understand a word of this and is thankful I have CB points and a carburettor?

[Beezabryan]

You are not alone Peter

[papasmurf]

[Thack]

I've been thinking some more about this, and I have a suspicion about these multiple pulses I've been measuring.



I cannot think of a single reason why it would be an advantage to spread the injection of fuel over two or three separate pulses. So I think it's not quite as I first thought.



Some modern injectors are designed to operate very quickly (reduced dead time) and they have a lower resistance so that more current flows in them, increasing the magnetic force on the solenoid. However, if the current were to continue for any length of time they would overheat and burn out. To avoid this, after the solenoid has actuated the ECU pulses the current in the injector, reducing the average current and the heating effect, but still maintaining enough magnetic force to keep the injector open.



It looks a bit like this:







The injector gets one strong pulse, and then it is held open for the rest of the time by a series of brief pulses. When these finish, the injector closes.



I thought this system was only used on high performance engines, but if it is used on our Bullet then I think I'm picking up these "holding" pulses and counting them. In other words, if I am correct in my suspicion, it is really only one injection pulse per cycle, but it includes some holding pulses within it.



I'm going to investigate further exactly what is happening and will report back in due course.

[Rattlebattle]

I look forward to that. For my part though I have just ordered the carb conversion kit from our host. This followed a recent thread on the same, the OP to which I am indebted as I had not realised that the latest version dispenses with the need to replace the generator, making it both considerably cheaper and easier to instal (he said hopefully). I admire those like Thack who have the tenacity and ability to understand fully and resolve the fuelling on these bikes and I do take an interst in the EFI system. For me though the cost involved in getting decent fulling throughout the range including tickover is not worth the benefit when compared to a carb, especially if, as Jefrs has indicated a PCV in itself is not sufficient. Also, having recently bought a new old style Triumph Thruxton, I would rather play around with the EFI on that, as it is a system that is fully understood and can easily be flashed with a suitable map according to mods made like exhaust systems, using free software (TuneEcu) and a cheap OBDII cable. No need for a PCV and a degree in automotive electronics engineering. Each to his own, but I do sincerely hope that someone fully cracks the EFI on these bikes before too long.

[Dennis C]

Rattlebattle TuneEcu is a brilliant bit of kit, be a bit careful buying the lead, also read the info on their website re setting the lead up before use or you may end up with the wrong spec lead or drivers, if in doubt email Alain for advice he is a very helpful guy.

[jefrs]

Does TuneECU work with the RE ECU? TuneECU say, "TuneECU is a software for reprogramming, diagnosis and testing of the Engine Control Unit (ECU) fitted to Electronic Fuel Injected (EFI) modells from Triumph, KTM, Aprilia Benelli, Ducati, Moto Guzzi,
Gilera & Moto Morini." So whilst compatible with Triumph, it may not be compatible with Royal Enfield; it is pretty easy to make an ecu go all buggerup.



Please confirm if you know for sure that TuneECU will work with the Royal Enfield ECU ???



I believe but cannot confirm that the Royal Enfield is similar in protocol to that on Harley-Davidson because of the way it interacts with the Dynojet Power Commander in a very similar manner.

[jefrs]

TuneECU goes on to say, for Windows, "For ECM Sagem and Keihin models: USB/OBDII cable with FTDI chip set and associated CDM (D2XX) ver. 2.06.00 drivers or higher. Note: for Windows 8 & Windows 8.1 from driver vers. 2.08.28, select here the driver package
for manual installation. From driver version 2_08_30, works with WIN 8 & 8.1, the automatic installation via Windows driver update."



The Royal Enfield ECU is a Keihin type and is (or should be) supplied with an appropriate USB cable*, but do we have the FTDI chipset (whatever that is). Window 10-&up tends to install correct drivers automatically.



* the ECU mini-USB (OBDII?) socket is the same as on many cameras.

[jefrs]

-> -> -> I've had a car ECU fried by a professional. I don't want that to happen to you.



It was an expensive mistake, very expensive. Fortunately his company paid for the replacement.