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Technical Megasquirt

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Technical Megasquirt

That's the one!! Correct me if i'm wrong about the seven pins, but that's what i'm looking at. 6 of them are actual metal pins, one is a dummy (missing) pin so you don't get the connector upside down.

Any idea on the pinout of that thing?
 
Nope...but!

The stepper is made of two coils. Check for continuity between all the pins. That way you can find the two windings...

then the last three pins, put the meter on resistance, and check that resistance changes when you turn where the spindle goes.

the TPS can be wired either way round.

The only issue is which coil pair is which, but thats going to tak two second to test in reality and will do no damage if wired wrong

:)

//edit. the last remaining pin will be 5v
 
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Use a multimeter on the buzzer mode and try to find if the above mentioned pins end to the 7 pin plug.
 
All common sense fails here - or i have a broken unit. One coil works, but i can't find the other one (tried all combinations, resistances are all over the place). The TPS seems to be malfunctioning as well, the only wire combination where i do get some sort of resistance change is in the range between 1.5kohm and 1.8kohm.

I'll try finding a different throttle body and IAC/TPS combination, see if that works...
 
kritip said:
Cheers for that :)

I presume on the MS PCB you have:

Code: 
1A/JS0 --> IAC1A
1B/JS1 --> IAC1B
2A/JS2 --> IAC2A
2B/JS3 --> IAC2B

Kristian
Click to expand...

Yep those jumpers are all installed. Think ive got the stepper figured out now. However onto the coils. Have mounted the second coil driver to the MS case. With the BIP373 i have a 330ohm resistor from R26 to IGBTIN for the first and then the second coil driver i have left leg to R27 and right leg to ground on right leg of R37. For the spark output it says if using a stepper not to use IGN, IAC2B, IAC2A or IAC1B, but doesnt say where to connect it to. Any ideas?
 
done some reading and tweaking.

I found a thread on ms forums about calculating injector opening times

I cant find the thread at the moment but basically you double the number of squirts required and if the AFR stays the same then the injector opening time is right.

I tried this with my open time at 1.1ms (iirc) I doubled the squirts per cycle and the engine ran super rich. So I then decreased the opening time until i got closer to the real AFR.

After a couple of switching and changing injector time I ended up with 0.940ms opening time.

I am shocked at the effect this has had, the car runs so much better. the engine used to start reving higher when stuck in traffic for a long time... now it stays perfect.

after a hot start it used to run a bit funny for a few seconds and now its spot on.

when doing datalogs and running them through megatune I used to get quite a large map drift where nearly the whole map will move up or down a few points from day to day... I did 3 large logs(wehey!) and each time there was almost no changes to the mapping!


From the megasquirt thread it was discussed that the injector opening time is just that, The time it takes the injector to go from fully closed to fully open. The maths within megasquirt assumes this is time where NO fuel is injected... but in the real world fuel is starting to flow as soon as the needle in the injector moves.
 
I also have to find some time to do that. I remember reading about it, but until recently the weather in Greece was a bit cold and had no problems with the VE table. Since some days now, that we get 20+ oC, car started to act erratic from day to day and had that problem of VE drifting every time i used to auto-tune.

I'll do the 1-2-4 squirts test asap...
 
Ms Build pretty much finished at last. :p

Have installed the PWM flyback circuit by accident. Guessing its fine to leave it.

The centre leg from BIP373 is the output signal, so that will be the one that connects directly to the coil pack? I now know why craig recommended mounting it in the Relay box but confused me at the time. So what pin on the DB37 should i use to run a wire to the relay board that will not affect anything else on the MS board Same for the Relay board itself?

Pretty excited now. Really appreciate the help through the build. :worship: Prob due another donation.
 
flyback is fine.

Coil driver mounting has different schools of thought. Ie :

http://www.diyautotune.com/tech_articles/using_bosch_bip373s_with_megasquirt.htm

or

http://www.msextra.com/doc/ms1extra/MS_Extra_Ignition_Hardware_Manual.htm#mulitcoil

If you have a relay board, I'd remove the drivers from the main case, and modify the pcb to run the ouput to two drivers on any spare output...SPR1-4 or the IAC outputs.

Personally, I'd ditch the BIP's altogether and do something like this:

http://www.microsquirt.info/Bosch_211.htm

but using a 2 channel version (see attached pdf)....it keeps noise out the way, and is designed for the engine bay :)
 

Attachments

  • ignitionmodules.pdf
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  • Thanks
Reactions: Dan
So, one 0 227 100 200 for wasted spark and two of them for COP is a direct replacement of VB921/BIP373 ? Do we keep the same resistors on the input?
 
Just when i thought i was getting somewhere. :p

I am using the DIYautotune method, but for the output (centre leg) it says use the IAC connections. Im already using them for the stepper motor. So i could just run a wire all the way into the engine bay from the centre leg?

Dont really want to complicate things more than i need to yet as its already a steep learning curve. Could follow step by step, but creating a new way to wire things up i think im stuffed. haha
 
You can route wires to engine bay mounted drivers, through pins 3,4,5,6 (spare pins, solder cable directly to the pin from the inside), or through an extra connector which you will have to mount below the D37 one.
 
Asteris said:
So, one 0 227 100 200 for wasted spark and two of them for COP is a direct replacement of VB921/BIP373 ? Do we keep the same resistors on the input?
Click to expand...

Yes, all you need is a 0 227 100 200 and then a simple mod to trigger each coil driver inside the 0 227 100 200 with a 5v signal. The mod is like this

http://www.msextra.com/doc/ms2extra/MS2-Extra_Ignition.htm#groundpull

That way the only signal coming out of the MS is a low power 5v. The drivers in the 0 227 100 200 are triggered by this signal and the supply and grounds are then kept well away from the megasquirt.

Note I haven't done this mod yet, but will be so i can run sequential coil on plug.



@D4NS -- Your method is fine, but instead of the IAC pins, do you not have the SPR pins available to use rather than run a wire directly?

I would recommended bridging from the DB37 solder point to the driver rather than using a solder trace on the PCB.
 
Did some tuning about injector opening times and battery correction (yeah, it needs fine tuning too, so you can avoid AFR drifting during fan/lights opening). I now don't have map drifting from VEAL session to session.

I also found some time to fine tune ignition map. Engine sounds healthier, pulls better and gained 3-7% better fuel economy (EGO correction was at 93-97% after ignition tuning and before one more VEAL session).

In case someone needs it, here is the ignition map (CR about 8.0:1).
 

Attachments

  • Ignition Punto75 CR 8.0.zip
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