'88 RX7 N/A
I'm just reviewing the assembly to make sure I didn't miss anything I need, and these are some things I was not sure about.


PWM flyback damping circuit: I don't have to install this step?

High current ignition driver circuit: Again, there is no need for this to be installed? I can skip #65 and go straight toi #66 for assembly?

 

You only need the PWM flyback damping circuit if you're using low-impedance injectors without a resistor pack.

You don't need the high-current ignition driver unless you're driving the coil directly (and not using the built-in ignitor).

 

Thats what I thought, thank you for the confirm. One more question if you will: Trying to get the RPM to register with the stim, it will come on (however very erratic but slightly adjustable) for no more then 10 seconds, then drop to zero. It doesn't seem to matter where I turn the R56. While the RPM is registering, D15 lights tends to light continuously, while D16 lights rarely and D14 flashes like it should. On the stim, the fuel pump lights, as does IDL. When the RPM stops, IDL stays on while the PMP shuts off and the Squirt LEDS all light continuously. Just soldering error?

 

what settings do you have? What firmware?

 

I have a V3.0 board with MS I using the latest msns-extra firmware (029q,s,t modified with easytherm for the 47K AIT resistor). As per the FAQ, the changes I've made were the pull up resistors on the LED's, the 47K resistor as mentioned above, and the 510ohm resistor for the BAC valve. However I did not change out Q4 yet, as I can't get a hold of a ztx688B transistor without paying $100.00.

Which settings did you want to know about? The tuning settings in Megatune?

 

well for the transistor, you can go to radioshack and pick up a tip120 as well for pretty cheap too. Then you can get some mica insulator (like the TIP125 flyback transistors already on the board), and attach it to the heatsink, and run wires to the through holes where the normal fast idle transistor would go. You should be able to find anything in the tip120 series for less than $5-10. (depends on how much ratshack wants to rip you off).

If you're going to use a ztx transistor, I recommend the ztx689 instead of the 688 since it's rated to 20v instead of 12v.

For the settings: yes, I mean the tuning settings in megatune. If you have done all your mods correctly, then these settings are the only thing that will change the MS's behavior.

For the potentiometers, you must turn them both all the way counterclockwise, and for the tach circuit, you must be sure to wire TSEL to VROUTINV.


Here is a link to where you can buy a ztx689 for $1.21. Digikey will charge you a $5 handling fee, and will charge you for shipping, so it might end up costing almost $10.
http://www.digikey.com/scripts/DkSea...823089&Site=US

Hopefully something here helps.

Ken

 

There are no radioshacks in Canada anymore I will try some of the other electronic stores however. And what are you talking about the heatsink for? Q4 is one of those moon shaped PN2222A transistors in the middle of the board.

I will post a modified screenshot showing all of the settings.

Yep, got that part.

Thanks.

 

the TIP120 is a TO-220 package... just like the other transistors on the heatsink. you could put it in place of the ignition driver, but don't bend the pins, and run wires to where the pn2222a would've gone.

 

Ahh, that makes sense. Thanks. I couldn't find one anyways, but I've ordered the ztx 689.

My MSQ as it stands:

http://www.sharebigfile.com/getfile....captcha=393630

 

I can use BDX53C to control the BAC idle valve?

 

No idea, I'll have to look that up and get back to you.

 

Datasheet BDX53C
http://www.fairchildsemi.com/ds/BD/BDX53.pdf

 

Give it a go. Looks fine to me.

 

yep, as renns says, looks fine.

 

Thanks

 

PWM flyback damping circuit: step 69 So ur saying that if u have a 86-87 s4 and are going to use a oem stock harness (wire in to it) with the oem integrated injector resistor pack in the harness wired inline between the ECU and injectors (under stock air box) w/the 86 low impedance (2-3 ohm) injectors skip to step 70
(No r30-r31-r34-r35-r32-r36-q9-q2-q10-q13) and u can’t use it at all if ur using high impedance injectors 88-91 right?

I need to clarify this because I have to do some reverse engineering lol
And the PWM flyback damping circuit is already in there i got the ms1 v3 assembled I have an 86s4 Na that I will be trying this out on then I will be installing an s5t2!
thanks

 

you don't have to remove the PWM flyback circuit if it's already there, you can just set the settings so that it doesn't use that circuit.

You can leave it out if you want though if you're building your own MS.