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Used MS2 V3.0 identification

James M

James M

Unknown Member
Joined
May 2, 2017
Location
Davis CA
I picked up a used Ms2 v3.0 today, out of an unknown car that the previous owner never used (fingers crossed it's not messed up).

It's set up for VR out and VR in but that's easy enough to change for my install. I'm more interested if anyone knows what the chip circled in blue (TC44276) is/does.
It's connected to both SPR3 & SPR4 along with R26 and R29. Worst case I'll just remove it but finding any other changes I may have to revert that are connected to this would be great.

Seems like SPR3&4 may be soldered into the bottom of the MAP sensor (MXP450ap). Although it doesn't look to me like that is possible?

D1 and D2 are also jumped (although there is a diode in the top of D1)

If anyone sees anything else out of the ordinary let me know

Here is an image so big you could lift my fingerprints off it
<a href="https://ibb.co/z2SXZNQ"><img src="https://i.ibb.co/rpZxHvF/MS2-V3.png" alt="MS2-V3" border="0"></a>
 
It is a FET driver for a logic level coil like a VW wasted spark smart coil.

See 5.3.1.3 Logic spark outputs - FET driver method in the MSExtra Hardware manual
(the only manual you should be using)
http://www.msextra.com/doc/pdf/MS2V30_Hardware-3.4.pdf

Jumpering D1& D2 is part of the old method of hall sensor config, the new method uses the VR conditioner circuit with R56 set to 2.5v.
 
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As Dirty Rick states, TC4427 is a driver IC and appears to be connected to the spark A and B outputs. Presumably it is set up to drive logic level coils in a 4 cylinder wasted spark configuration. Presumably you have the MS Extra firmware loaded on the board rather than the original B&G firmware.

By-passing D1 and D2 is standard practise when using the optical input with a Hall or Opto sensor. Your board may be set up to accept a missing tooth crank trigger wheel using a Hall / Opto sensor or a Vr sensor.

Perhaps best to power up the board and connect to Tuner Studio to confirm which version of the firmware is loaded and what the various settings are.

As an observation, the mounting of the TC4427 chip on that add-on board in the proto area and the connections to the board look a little cobbled. You can purchase nice surface mount adapter boards from Sparkfun, Adafruit, Proto advantage and probably others. If you plan on keeping that arrangement for wasted spark, I would consider coming up with a more secure arrangement - something that is less likely to fail in the middle of the night at a bad time. When using the spark A and B outputs, you don't need those resistors (or the LEDs or transistors). Remove the resistor and solder the jumper wire directly into the hole which makes for a much more secure connection. Tacking the wire onto the resistor lead is poor practise.
 
I'll add a couple other comments.

For the TC4427 wasted spark driver, you can also get the IC in a through-hole DIP 8-pin package. I'm guessing someone ordered the part in the wrong package (surface mount) and adapted it with the small bare-copper PCB, instead of re-ordering the right package.

On the top heatsink row, Q9 and Q12 should be fastened down using a mica insulator. Currently, if they touch the aluminum heatsink bar, it will short +12volts to ground. Search for "TO-220 Mica insulator kit" at DIYautotune. Alternately, you can just remove Q9 and Q12 -- they're only used for Low-Z injectors in PWM mode, and Low-Z has other problems so you don't want to use it.

If you want to control a LH2.2 or LH2.4 idle valve, you'll need a DIY "PWM IAC Valve Control Mod-Kit" with another power transistor (goes in the empty position on the far right of the heatsink bar).
 
Thanks for all the information, cleared up a lot of stuff. I'll try powering it up today and taking a look at the firmware it's running and settings applied. Awesome tip on the Q9 and Q12 as I probably would have used bolts to mount them and shorted it. I've been reading threw an older version of the MS2V3.0 hardware PDF but the updated one will be my gospel now. Seems like my best bet is to "restore it to stock" and work from there setting it up.

This is my first time around with megasquirt and getting a "project ECU" was substantially cheaper($100 for the ECU, half a harness, some ebay turbo and header for a honda or miata or something). In all likelihood this will end up on my datsun as I'm much more happy with how LH2.4 and M4.4 are preforming on my Volvos then L-Jetatronic is doing on my Z. Not going to even try Datsun forums as most are dead or full of people that know even less then I do
 
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