Relay Board wiring MS3X w/ Relay Board

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craigibc
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Relay Board wiring MS3X w/ Relay Board

Post by craigibc »

I want to start with some background first so you can assist me with these issues. I did not assemble the megaquirt or relay board it was installed in the car when I got it. I just rewired the car (62 Ford Falcon) and I wanted to put a weatherpack connector in the firewall and make sure this is wired correctly since the car has not been driven since it was installed. It has run but never enough to drive it any distance.

I went through the engine bay and traced every wire and labeled in accordingly and also the same under the dash to the relay board and megasquirt.

My first issue is I am hung up on a few wires going into the relay board and underdash.

I have certainly printed and reference the online documentation but I am still confused about a few wires.

2 TPS wires coming from the engine bay.
cam sensor wire from the engine bay.
cam sensor wire coming from the megasquirt plug
IAT wire from engine bay.
IAC wire from engine bay.
yellow red and black from the LC1

If you could point me in the right direct where I install these wires it would be amazing.

http://www.bgsoflex.com/mspower/mspower.html

This is the latest reference point for the wiring I was using today.

If I am posting in the wrong place can the moderator please move it to the correct forum.

Craig
Matt Cramer
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Re: Relay Board wiring MS3X w/ Relay Board

Post by Matt Cramer »

craigibc wrote:I want to start with some background first so you can assist me with these issues. I did not assemble the megaquirt or relay board it was installed in the car when I got it. I just rewired the car (62 Ford Falcon) and I wanted to put a weatherpack connector in the firewall and make sure this is wired correctly since the car has not been driven since it was installed. It has run but never enough to drive it any distance.

I went through the engine bay and traced every wire and labeled in accordingly and also the same under the dash to the relay board and megasquirt.

My first issue is I am hung up on a few wires going into the relay board and underdash.

I have certainly printed and reference the online documentation but I am still confused about a few wires.

2 TPS wires coming from the engine bay.
The easiest way to check a TPS is to unplug it and put an ohmmeter on its pins. Observe the resistance as the throttle opens and closes. Each pair of pins will behave differently:

The resistance between the VREF and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the VREF and signal pins will be high with the throttle closed and low with the throttle wide open.
cam sensor wire from the engine bay.
cam sensor wire coming from the megasquirt plug
Cam sensor normally goes to the MS3X and does not tie into the relay board.
IAT wire from engine bay.
To the MAT terminal on the relay board.
IAC wire from engine bay.
If that's a two wire IAC, it could go to the FIDLE terminal with the idle relay jumpered, or to IDLE on the MS3X.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
craigibc
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Re: Relay Board wiring MS3X w/ Relay Board

Post by craigibc »

Matt,

Thanks for the reply I will try and knock these off one wire at a time.

So looking at the list:

The easiest way to check a TPS is to unplug it and put an ohmmeter on its pins. Observe the resistance as the throttle opens and closes. Each pair of pins will behave differently:

The resistance between the VREF and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the VREF and signal pins will be high with the throttle closed and low with the throttle wide open.

I will test this after work today. Once I determine the wires does one go to vref and the other to tps on the relay board?

Cam sensor normally goes to the MS3X and does not tie into the relay board. Done figured that out thank you!
To the MAT terminal on the relay board. excellent thanks again!

If that's a two wire IAC, it could go to the FIDLE terminal with the idle relay jumpered, or to IDLE on the MS3X.

It is a 3 wire IAC 1 is signal and 2nd 12v power and the 3rd is ground So I am going to assume I am going to plug the signal wire into FIDLE on the relay board.

Now I am down to the wires on the LC-1.

Right now blue and white around going to ground. Brown is going to O2 on the relay board, red to switch 12v, still do not know where to plug in the black and yellow.

Thanks again for your help!
Matt Cramer
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Re: Relay Board wiring MS3X w/ Relay Board

Post by Matt Cramer »

Correct on the TPS.

Black is the calibration wire and yellow is for a gauge (if used).
Matt Cramer -1966 Dodge Dart slant six running on MS3X
craigibc
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Re: Relay Board wiring MS3X w/ Relay Board

Post by craigibc »

So I do not have a a gauge for the LC-1 but I do have a light that flashes as the O2 sensor warms up and also a reset button to reset the O2 sensor when needed.

So how do I wire the the calibration with the reset switch and also the light?

Craig
craigibc
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Re: Relay Board wiring MS3X w/ Relay Board

Post by craigibc »

Got the TPS figured out thanks!

Once I get through the LC-1 wiring I am close to putting it all back together.

Craig
Matt Cramer
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Re: Relay Board wiring MS3X w/ Relay Board

Post by Matt Cramer »

Personally, I usually just tape off the calibration wire. But if you want to use it, see the LC-1 manual: http://www.innovatemotorsports.com/supp ... Manual.pdf
Matt Cramer -1966 Dodge Dart slant six running on MS3X
craigibc
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Re: Relay Board wiring MS3X w/ Relay Board

Post by craigibc »

Thanks Matt this is the answer from the manual!

Connect the LED and momentary pushbutton between the LC-1’s
BLACK calibration wire and ground. Connect the red wire (Anode)
of the included LED AND one side of the push button to the
calibration wire (black) of the LC-1. Connect the black wire
(Cathode) of the LED AND the other side of the push button to
ground (preferably to the same ground point as the blue and white
wires.) Refer to the schematic below.
Note: The LED will fit a 5/32” (0.155” - 0.158”) hole size and a
panel thickness of 28–16gauge (0.031” - 0.062”).

Almost got the wiring all back together and ready to install!

Craig
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