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mpbarrett

basic MS3 wasted spark ignition question?

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I have started to fit a Megasquirt MS3 to a 1500 Herald. At the moment I am aiming to get the ignition working before fitting the injection system.

I am driving  ford wasted spark coil, driving directly from the MS3. I am using the IGN output and the SPR4 outputs. The IGN output works fine drives the coil and give a nice spark, the SPR4 is connected to a Bifet and the Bifet driven from pin8 (PM4) from the processor socket. There is no spark from the coil when driven from this output (SPR4). Checking with a scope and going back to the pin 8 on the processor there is no pulse coming out of the processor to drive the Bifet. I realise that maybe I have to somehow define the output or is it done automatically in the TunerStudio settings?

I have it set under Ignition options to "Wasted spark", "MS3X spark". the timing wheel stuff is 36 teeth with a missing tooth, that all works as I have tested it.

If I have to set the output up how do I do it?

I have read a lots of Megasquirt forum posts and manuals (there is a lot of information out there)  but just cant see the answer...

regards

mike

 

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Hi Mike,

Have you really not been on here before or do you have an old account you can't get to work anymore? Welcome anyway :-) 

I've not got as far as MS3 myself but if it fits the pattern of earlier versions you are going to need to define what the SPR4 is being used for.  There will be a dropdown in Tuner Studio called something like "extras" or "additional outputs" but difficult to be precise as these can vary with firmware version and are not always very logical.....

Nick

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2 hours ago, Nick Jones said:

 

Hi Mike,

Have you really not been on here before or do you have an old account you can't get to work anymore? Welcome anyway :-) 

I've not got as far as MS3 myself but if it fits the pattern of earlier versions you are going to need to define what the SPR4 is being used for.  There will be a dropdown in Tuner Studio called something like "extras" or "additional outputs" but difficult to be precise as these can vary with firmware version and are not always very logical.....

Nick

Hi Nick

been a listener for awhile. The Herald EFI has been a long slow burning project, spent too much time playing with my TR6 and Lucas injection and the alps (no easy solution).... The TR6 has gone and now I only have the Herald and have come back to playing with it. Done all the difficult bits (wiring and setting all the sensors up) now trying to get the software working at least starting with the ignition and then moving onto the injection.

Will see if I can sort out the options. Its a great system but almost too much information.

cheers

mike

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There is too much information.  Plus it's got so big that the people who know are bored with answering questions.  The information will be out there but finding it...... :huh:  Was alot easier when I started (12+ years ago :o)

Doing one part first is a good idea and ignition is probably the easier one set-up wise.

 

Nick

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Bit of progress. :)
Realised the firmware was very out of date so have loaded the latest version (from 1.1.2 to 1.5.1).

Set the Spark hardware to use to LEDS spark  and that makes it use the PM4 to drive the second coil driver Bifet. Now outputting pulses on both coil outputs (using a pullup resistor to simulate the coil and viewing the output on a scope). So at least its working with the Sim board in the office! Will do some more basic checking and then put it back in the car.
Once I have got some sparks I want to check the timing as I am not convinced I have got it right yet... and then see if I can start it!

cheers

mike

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Sounds promising.

Basic timing should be right if you've got the trigger wheel in the right place and if it's just few degrees out than it should be possible to apply an offset in software to correct it.  I guess you'll also need to set dwell - something I've not had to do as I'm still using EDIS.

All you have to do then is to get the plug leads in the right order (and fire the coils in the right order).  I always find this a challenge for some reason, though in my defence I'm usually working on sixes.......

Nick

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Finally got it running today. I have run the Ms3 on the simulator, hooked up my scope to all the signal, drunk far too much coffee and obsessed about the sparks and the timing.. But forgot you need petrol to make it run....

Lots of cranking to get fuel (still on the mechanical pump and it hasn't run for about 5 weeks) into the carbs and it started. Have added a big pipe to get the fumes of  the garage and tomorrow will start to play with the settings. Time for wine :) 

Mike

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This is an interesting journey... It would run but started to misfire when the rpm was increased. Lots more analysis with the 'scope. One of the problems was that the timing wheel was not running true on the pulley, so the mark space ratio from the wheel was varying.

Put it in the lathe and trued it up but noticed that there is some damage on a couple of teeth, so have ordered a new wheel (this one was a used one from a friend). After trueing it up and refitting it was much better but wont go above 3000 rpm before it starts to loose the pulses, the RPM drops (well the MS3 thinks it has) and starts to misfire. I am using a industrial hall effect device (just happened to have it available) so is more sensitive to gap between the teeth and sensor. At tick over the stability of the timing is amazing after the standard distributor.

Will fit the new wheel when it arrives and check that the Hall effect sensor has a large enough bandwidth, if not might change it for VR one. Getting the timing working seems to key to the MS3.

Lots of work but learning a lot about the MS3 and its capabilities, it is very impressive, the diagnostic capabilities are good once you understand them but glad I understand electronics and have the tools to sort the sensors.
 

mike

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I've not had to dig into that as the EDIS unit takes care of it.  Doesn't seem to be very fussy about air gap.  EDIS uses VR sensors.

Something else that EDIS takes care of which seems to create problems is coil dwell/charge time, which can be another cause of misfire at higher rpms.

Sounds like you are having a good learning experience though and building up useful knowledge!

I remember being amazed when I first ran the Vitesse on EDIS (it had already been on injection for about a year, triggered by the points!) as it idled like a clock for the first time ever - I knew before I put the timing gun on it the marks would be rock steady - and they were.

Nick

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time to update this.

New trigger wheel fitted to pulley and trued in the lathe, new VR sensor. Reset timing and tuned carbs again and its running very very well. Staring is much easier and car pulls in all gears, very impressed.

Now put it back in garage ready to start on the fuel injection. I think I have everything I need (lots of Ebay purchases paid for by selling my TR6 bits). The plan is to put a banjo connection into the drain plug of the tank to get a second pipe into the tank, I don't think I can get it out without breaking the tank so will drill and tap it in situ. I have a pump and everything else ready to go. I have got the throttle bodies ready and sorted the vacuum pipes and idle setup.

cheers

mike

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