alright, i am at the point where i have to setup the MS unit for different things. The unit is being used for just fuel at this time, but i would like to leave the ignition circuits in anyway for later use if i want.

With that...

1. Imput Section (step 50 in the manual)
Hall/optical/etc input circuit vs. VR circuit.

i am assuming by what i have read on here, that i want the VR circuit for the tach signal? But if i am using MSD boxes, i would be using the tach out from the MSD box then. So what is an MSD 6a then? VR or the other?


2. about step 63 there is talk of the output circuit. Not sure if i need the high current driver or not.

3. what is the PWM flyback circuit? Do i need it?

 

1. If you're using the tach-out from an aftermarket ignition, I believe that you would use the Hall/optical/etc input, although I'm not certain on this having never played with one of those boxes. Build both the Hall and the VR circuits though, since if you are ever going to use the stock CAS, you'll need it and its much easier to switch the jumpers. What does the MSD 6a use for its timing signal?

2. The high current driver refers to a circuit that can be used to directly switch ground to a single coil. You need this if you are directly controlling a coil. Again, I dont know about the MSD 6a, but for the stock ignition you dont need it, although it never hurts to have it there if you ever decide to go a different route

3. The PWM flyback circuit is there for protection against the higher current of low-impedance injectors. If you're running high-imp injectors, you dont need it, but again it doesnt hurt to have it, epsecially since many of the larger injectors that can be used as secondaries for FC's only come as low-imp.

 

so basically if i just build everything onto the board, it will be fine?

what about that one diode? D52 i think? I've heard it called the "wing" diode

 

For 1, 2 and 3, just build it. You can select between your ignition input circuit with jumpers. You will need the opto/coil input to stimulate, and the VR input to read the FC CAS. Hence, make both. You don't really need the high current ignition driver but you might as well include it. You'll want the flyback circuit if you are running low impedance injectors. Might as well include it as well even if you are running high impedance.

You only need the wing diode if you are triggering from the negative side of the coil.

Also decide whether you want BAC control. If you do, there are a few differences during the build and it's a LOT easier to do it now then having to unsolder parts later.

 

i do not need BAC control. But that was mentioned earlier in the manual correct?

i believe that we are using the MSD box output for triggering so i can leave out the D52 diode correct?

I have a good de-soldering iron (thankfully)

 

For MSD-derived ignition input just use whatever you'd use for points input, or otherwise reading off of the negative lead of a coil on a generic distributor car. Only you will not have to worry about noise, because the MSD delivers an awesome noise-free signal. (Which is another reason MSD rocks)

 

Skip step 50 all together and start on step 51! This is where it gets confusing for some people because right off the bat it says as we noted in step 50??? They just told us to skip it!

Just skip step 50 and go to step 51, do step a through k, now on step 52 set the jumpers on the bottom side of the board to VRIN to TACHSELECT with a left over wire from a resistor leg cut off, and the other to TSEL to vrout with a piece of wire.

Step 54, change the resistor R4 to that 49K resistor you got from radio shack for the temp sensor.

After you finnish you will have to do the pull-up resistor mod and add in the second VR circuit to run the stock CAS and coil packs.

Let us know if you got that far and need help, i'm sure one of us can come up with pics and diagrams!

 

Correct, you set the 'Squirt up to trigger from the coil when triggering from the MSD output. I've recently done this with a (yuck) V8 car and the signal was fantastic.

 

what is R4 used for? Mazda sensors?

Also do i need the pull up resistor is i am not using the ignition?

 

It's the bias resistor for the Mazda manifold air temperature sensor. It has a weird range of resistances, which makes it necessary to change the bias resistor.


You don't need the pullups if you're not controlling ignition.

Ken

 

thanks for all the help, i should be able to finish everything tonight

 

FWIW, I'm just using a GM intake sensor and the Mazda coolant sensor with no recalibration. The coolant reads 10 degrees off, which is close enough when you're doing the tuning anyway.

The GM CTS is super cheap, and I think the turbo Dodge stuff is the same part anyway.

 

i may just leave off the resistor and just use GM stuff since i am not using Mazda manifolds anyway.