I am working on a 87 RX-7 using a home built (not plug n play) MS1 V3 Board. The box was built to run using a single VR sensor. The Wheel Decoder, Codebase, and Outputs are setup according to he MS1 guide stickied on this board.

I have the box powered and grounded to the chassis. I am getting a volt reading of 12.0. The only other wires hooked up at the moment are Pin 24(ignition) to the RED CAS wire (NE+) and Pin 7 to WHITE CAS wire (NE-). The CAS is not installed in the car, I am manualy spinning the gear checking for RPM.

The Wheel Decoder is setup as following -


Can anyone tell me what I am doing wrong?
Thank you very much,
Chris

 

I run an S4 modded CAS as well and those setting match mine. You do have the right code type selected in "code base and output functions" right?

 

It is set to Wheel Decoder (ON).


The engine is not grounded at the moment but I did not figure that mattered as long as the ECU had good power and the CAS was plugged in.

 

Are the jumpers on the board configured correctly and the pots fully counterclockwise?

 

Thank you for chiming in. I will be at the garage tomorrow. I will check the pots (blue box's) and set them correctly. Where should I look for the correct jumper configuration?

 

From the Megamanual:

-Jumper VRIN to TACHSELECT on the bottom side of the PCB (near the DB37, opposite the heat sink.)
-Jumper TSEL to VROUT (Or VROUTINV if you want the VR input to be inverted) on the bottom side of the PCB, near the center.

 

Thank you very much Aaron Cake and Craiger for your input. I am going to work on the car right now, 6 port turbo build

 

Jumpers are correct, VR pots are set just before the clutch click counter clock wise.
TSEL is set to the VROUTINV, what is the difference? I will go look for the answer in in the manual but if you do not mind answering the question before I can find it then GREAT

Once again, Thank you very much for your help. We are really excited to get this car running.
Just in case you are curious it is

6 port turbo
700cc injectors x4
255 Walbro
50mm wastegate
Full 3 inch to duels
MS1 V3



Thank you again, I will be trying to get tach signal for the rest of today, checking the thread frequently.

 

VROUTINV inverts the VR signal, which is the correct setting for an MS1.

Do you have access to a scope?

 

I do not believe I have access to a scope. I will find out soon if I do.

 

It sounds as though you aren't getting a VR signal, which I would suggest tracing through the circuit with a scope if you can get access to one.

 

Ok, if I do not have access to one would you have any idea of what my options are? What would you be willing to charge to look the board over for me if that is an option.

Thank you again very much.


Chris and Jon

 

Do you know anyone who does an electronics work, like TV repair or such? They can probably troubleshoot the circuit fairly easily.

I'm not willing to do it, sorry. I don't involve myself in other people's projects as it turns into nothing but a huge time hole for me.

 

Check the VR sensor to tooth clearance. This often gets opened up a bit big during the CAS modding. Also, try spinning the CAS a little faster: punch out the roll pin, pull off the helical gear, and throw the CAS shaft into a drill chuck.

 

Today I adjusted the VR sensor tooth clearance, spun the CAS faster and took the box to a TV repair shop.

The TV repair shop did not have a scope but used a multimeter to tell me that transistors Q22 and Q23 were not functioning due to a short somewhere on the board.
So I need to go over the board, new transistors were ordered to replace the bad ones (Q22 and Q23)

 

What kind of TV repair shop doesn't have a scope?!

 

Dude, I have no idea.

AN fitting was welded to the oil pan. Down pipe is getting fabbed this week. All that is left if the intake pipework and Megasquirt to function properly. Waiting on the new transistors to come in.


Thank you for the assistance Mr. Cake.