I'm ordering the v3.0 board tomorrow from Glen's Garage. I'll also be ordering extra parts from Digi-key. Since I plan on using the stock CAS, i will use the VR on board sensor and build the second.

Here's the parts list i have so far:
1. Megasquirt v3.0 kit from Glen's Garage.
2. (VR Circuit)
A. 1-lm1815
B. 1-4.7K resistor
C. 1-82K resistor
D. 1-18K resistor
E. 1-0.33µF capacitor
F. 1-.01µF capacitor
G. 1-330pF capacitor
3. 3-4.7Kohm resistors

I'm still a little confused on what to use for the BAC. As i've read it, the transitor that comes with the 3.0 kit tends to burn up. I have Muy's instructions:
1) First, remove Q20 and R39. Replace Just jumper R39 instead.
2) Replace R19 with a 510 ohm resistor.
3) Replace Q4 with a ztx688 (orient it with the flatter side the same direction as the flat spot on the silk screen) Leave a little bit of space under the ztx688 when you solder it.
4) remove D8
5) Using a 1N4001 Diode, jumper pin 3 of the ztx688 to a +12v source. The banded end of the diode goes to the +12v source.

So i would need.
4. Idle Control
A. 1-510 ohm resistor
B. 1-ztx688
C. 1N4001 Diode.

Anything i'm missing?

 

That should all be good...

You might consider just getting the msns-extra daughterboard... even if you're not going to use everything on it, it's a lot cleaner...

Also, when you build the v3 board, be sure to use vroutinv instead of vrout when you jumper the vr conditioner to tsel. Also be sure to start out with the POT's all the way counter-clockwise.

Ken

 

Is this something new? First I've heard of it--guess it's good I havent tried the ignition yet.

Scott

 

Yeah i have to say i'm confused on that as well. I can't find information about that in the instructions. Are you talking about just for the second VR that'll build in the proto area?

 

No this is a jumper on the v3 board that is set during step 52 of the tach input circuit.

MTB, do you know if it will still read the tach (trailing coil) input if using vroutinv?

 

Why would it need to read the tach from the trailing coil if it's reading it from the CAS?

Oh and i think i understand what is meant by the jumper. I went over the instructions on the site again.

 

Cause right now I'm running without the CAS signal in a fuel only piggyback mode and just using the trailing coil for rpm. The jumper is soldered in place, that means once I change it there's no going back to the fuel piggyback mode--unless of course I unsolder and resolder but that sucks.

Of course, if the vr circuit will properly read the trailing coil for rpm in the vroutinv mode then--no problem.

 

It's not really new... I just never posted the info b/c I never thought about it until recently... it needs to be inverted b/c the MS1 chip can only trigger off the trailing edge of the pulse from the vr sensor conditioner.... and that pulse has to line up with the point where the signal from the VR sensor crosses zero volts going from positive to negative.

Ken

 

I can't think of any reason why it would read differently ... it'll just trigger off the other side of the pulse from the coil...

I find it weird that you're triggering from the trailing coils...

it seems to me that you'd want a pulse every 180 deg if configured like a 4 cylinder... which means you'd want to connect to the negative terminal of the leading coil.

Ken

 

Basically I'm triggering from the exact same wire the stock tach meter is hooked up to--it's connector F-39 on the FSM wiring schematic. I thought that was where everyone hooked up a tach to.

 

So are you talking about swapping the VR circuit on the board itself?

 

As long as it has a pulse every 180 degrees that's fine

 

No, like Rex4Life posted, there is a build option when you're building... there'll be a step where it tells you to jumper TSEL to VROUT or VROUTINV.... you just jumper TSEL to VROUTINV instead of VROUT.

 

Okay, gotcha!

 

I think most people are connecting to the leading ignition coil, either directly to the negative terminal on the coil, or that black test wire that comes out of the coil/ignitor assembly.

 

Parts are in! I'm going to start soldering today after work.
I got the stimulator together last night...it seems to be alright

 

How's it coming?

 

Well i have the power circuit wired in and working. Then i realized i didn't have the serial cable to connect to my computer so i could check as i go, and then i discovered that no one in the entire state of colorado carrys them! So now i'm waiting for one i ordered to come before i continue.

 

Anyone know which pin on the zt688 is pin 3?
Is it E, B, or C??

 

Its pin c the collector. Looking at the transistor from the flat side with the label it goes from left to right E,B,C emmitor base collector or 1 ,2 3. Check the thread v3 board idle control muy describes it in detail.

 

Cool, all i need to do is find a 12V source and use a diode to jump pin three to the 12V. I'll do that tomorrow i think when i'm building the 2nd VR sensor and other things.

BTW, the thing works at the moment! I've got all the stock wiring done and it works! I'm excited.

 

I just finished my MS1 V3 megasquirt.
I borrowed your shopping list. While I was making my 2nd VR I noticed your missing a 1Mohm resistor for the VR Circut on your list.

 

You're very right, i am missing that but did order one (several actually). Unfortunately i can't update my shopping list for others. The 1Mohm resistor is important.

I have the VR circuit build in the proto area of my V3 board. I'm going to post pictures of my build later when i get home from work. I'm not certain if the VR circuit is working, but i have plans on verifying it this weekend. (Not doing anything else for Christmas)

 

make sure you change out the bias resistor for the air temp sensor (if you're using the stock air temp sensor) as per the FAQ. I noticed that you didn't have a 30-50k 1% resistor in your shopping list...

 

Hmm...i think i forgot about this as well...
Isn't it possible to reprogram for the change in voltage? I thought i read that in the assembly instructions, but maybe it was for the MS2 only.