MS2 V3.0 - About to begin wiring installation

[frogcow]

Hello I am back again, it has been ten years since my last brush with the Megasquirt bug.

This time I have purchased and assembled a MS2 V3.0, tested with stimulator ok.

I have read the manuals over but need a bit of clarification. Please see my signature for specifics.

My first query is ignition related. I currently have a coil (similar to a Bosch GT40) and an igniter attached to it. Does the high energy ignition circuit (BIP373 modification) replace the job of the igniter?
This particular charade engine (CB80) has a cam driven VR Sensor that I want to use, (24/3) reading from previous posts it seems that this configuration has been added to the supported list so am I right in guessing this will only be a tuning parameter selection in TunerStudio.

Secondly Fuel injectors I have three, am I right in guessing that I run all three off them off the same batch (pin 32 on the DB37). I have installed the PWM circuit . Firing sequence is 1,2,3.

Thats it for now but probably will have some more in the near future.
Thanks

[rickb794]

Yes the BIP373 is a Bosch ignition output and will directly run a coil.

Yes you can connect all 3 injectors to one channel, as long as they are not low impedance.
See section 4.10.2 of the manual.
Remember with one injection channel for 3 cylinders you will not be able to use "alternating" squirts and you will need to use a number of squirts that is divides into the number of cylinders (Probably 3).
Hopefully this motor has port injection and a long runner intake to store the fuel.

If you have any fueling issues I would look at doing sequential injection (which will need crank and cam position sensing (720°cycle) and matching injection drivers).

[frogcow]

I have updated the information in my signature, yes the injectors are low impedance.

Yes the motor has port injection and nice long runners.

Just keen to know how to wire the injectors up, so I have three low impedance injectors, one for each cylinder, firing order is 1,2,3. I have the Injector PWM circuit and flyback circuit installed. As per the hardware manual 4.10.2.3. I wire up the positive 12 volts to one side from the fuel pump relay via 15A fuse. Unsure about the negative, does it go to pin 32 and or a combination of 33,34,35 on the db37 loom. I have seen other squirters use sequential injection with this engine and this may be something to aim for in the future however I am pretty confident it will run with just the VR sensor in the distributor on the cam to begin with.

[frogcow]

Okay after some reading over manuals and installation guides, it appears 3 low impedance injectors can be wired to one driver providing it is a v3.0 board with the PWM flyback circuit installed. (Which is what I have).

I did see there is a hardware upgrade to install another pair of drivers and I think this is what would be required to run full sequential. Can anyone confirm if this is right?
Thanks

[rickb794]

If you decide to get sequential you will need 3 identical drivers. It would not be practical to try to duplicate the existing driver circuit, and i am not sure the software could do current control on a third injection channel. For low impedance injectors I prefer Peak & Hold drivers. It may be easier to switch to high impedance injectors.

[DaveEFI]

Yes the BIP373 is a Bosch ignition output and will directly run a coil.

Yes you can connect all 3 injectors to one channel, as long as they are not low impedance.
[Snip]

I have four injectors per channel on my V8.All low impedance with no series resistors.Driven PWM. What the V3 board was designed for.

[racingmini_mtl]

If you decide to get sequential you will need 3 identical drivers. It would not be practical to try to duplicate the existing driver circuit, and i am not sure the software could do current control on a third injection channel. For low impedance injectors I prefer Peak & Hold drivers. It may be easier to switch to high impedance injectors.

Not only is it not practical to duplicate the existing driver circuit, it is not possible to use the current drivers if you go to the 4 driver setup unless you do some significant board modifications and circuit modifications. And you definitely cannot use current control on any of the 4 channels.

So you either need peak&hold drivers or you need normal saturated drivers and current limiting resistors.

Jean

[rickb794]

Does the motor use some goofy type of injector that makes it impractical to switch to high impedance?

[frogcow]

rickb794, the cb80 engine comes from the factory with high impedance injectors however I have sourced some lower impedance injectors with a slightly higher flow rate that have the same physical design. The cb80 engine has a vacuum operated fuel pressure regulator that keeps manifold pressure at 2.5 bar. So by using the slightly higher flow rate of the lower impedance injectors coupled with the extra 0.5 bar of pressure they are rated for and then if I add an adjustable fuel pressure regulator and up the manifold pressure to 3.0 bar then I will achieve the extra fuelling I need to complement the improvements to the intake and turbocharger.

The reason I am getting hung up on this is partly because I have purchased a relay board and relay cable. I have looked through the wiring diagram to wire it up without the relay board but the cable I purchased doesnt have all the ground wires so I am torn on wether to modify the harness or bypass the injector wiring straight to the Ms2.

Any tips to get past this without buying another cable.

[frogcow]

I just pulled the db37 connectors off the relay cable and it seems the only difference is the location of four ground wires. So what I could do is cut the relay board end of the cable off completely and wire into a new engine loom and just remove the four ground wires from pin (8,9,10,11) and reinsert them at pins (15,16,17, 18).

[DaveEFI]

My view of the relay board is you are simply introducing more connectors where non are needed. Things like sensors are best wired direct to MS. If you wish to keep the relay board, use it for power only. Which would mean modifying its interconnect cable, or just making a new one.

[rickb794]

First I must say that is is not recommended to run low impedance injectors with a relay board.
The reason for this is both grounding as you have discovered but also the length of the parallel run of wires with high current noise on them.
The relay board is a legacy product that was designed for the v2.2 main board, and because of backwards compatibility happens to work with the v3.0 & v3.57 boards
You are totally on your own here treading into uncharted territory and you may ruin an expensive relay cable AND fail to get a clean install.
My recommendation is to return the relay board and cable for a pigtail harness and purchase a pair of relays, sockets, and fuse holders from the auto parts store and wire it up.
I have done a few relay board installs and have had problems on all but one. It was a basic system on a Ford TFI that ran great but radiated so much noise it messed with the USB interface.

You could modify the MS end of the relay cable and break out the grounds and injector wires (to eliminated the known issue), but besides bastardizing a relay cable you are defeating the whole idea of the relay board.
And there is still the possibility of problems with ground loops or some other unanticipated nuance.
Like I said you would be sailing uncharted waters and risking $185 in parts that $75 worth of parts would replace plus the headache and time.

[frogcow]

As per the general consensus the relay board has gone to a better home.

The distributor of the relay cable confirmed that the only difference with the relay cable and pigtail harness is the location of the ground wires from pins 7-19.

I have attached my wiring diagram, any chance I could get another set of eyes to look over for problems?

Also I have attached an msq and datalog, again if I could just get someone to have a look over them to see any obvious problems.

I am still waiting for the 50 Watt 40 ohm resistor for the PWM IAC valve before I will get it running again.

Thanks
David

[rickb794]

First the power for the O2 controller should be switched off the fuel Pump relay output.
This way the O2 is not powered up unless the motor is running.
The spark coil should not be powered when the fuel pump is off either.

Grounding the board (especially with low impedance injectors) is critical.
I would run pin 37 to the motor and ground the MAT CLT & TPS at pin 7.

See page 14 of the manual http://www.msextra.com/doc/pdf/MS2V30_Hardware-3.4.pdf

[frogcow]

First the power for the O2 controller should be switched off the fuel Pump relay output.
This way the O2 is not powered up unless the motor is running.
The spark coil should not be powered when the fuel pump is off either.

Grounding the board (especially with low impedance injectors) is critical.
I would run pin 37 to the motor and ground the MAT CLT & TPS at pin 7.

See page 14 of the manual http://www.msextra.com/doc/pdf/MS2V30_Hardware-3.4.pdf

Thanks I will look into that

[frogcow]

I have made some changes to the wiring, please see the attached diagram, really want to utilise the oem fuse box in the engine bay to keep it all tidy. I dont mind changing things around a little to accommodate it.

[frogcow]

I have tried to start it today with the PWM valve unplugged as I am still waiting for the 50W 40 ohm wirewound resistor.

No spark from the coil though, will have a better look tomorrow.

[LAV1000]

Looked at your diagram, have some remarks.
Like Rick sat, its best for O2 sensor to switch (LC2 relay) when fuelpump relay is on.
Same goes for injectors.
Missing the BIP373 ??

[rickb794]

Is TS showing RPM? Sync?

Also regarding the O2 sensor ground, if the O2 controller only has one ground it should go to the motor.

The sensor ground and the Heater ground are separate on many controllers.
You don't want the heater current flowing through the MS,
and the controllers have proven to be very noisy so moving that ground to the motor will keep the noise away from the MS.

[frogcow]

I have made some more changes as per recommendations. Please see updated wiring diagram below.

I also gave it another go this morning, with key turned to start the fuel pump runs, however there is no voltage across the coil hence no spark.

I also rechecked the timing and threw in a new battery for good measure. Will have another look on the weekend.

Please find a .msq and .msl file attached from this mornings start.