Confusion about mpguino pinout

[gone.st]

I just purchased a mpguino to install in my 2005 Toyota Echo.

A couple days ago, I installed the approrpriate wiring for the car. Some decently heavy gauge wire (16 gauge I think). Two wires go through the firewall. These two wires are the ground and injector wire. The ground wire was stripped and attached to the engine using a bolt from the injector manifold. The injector wire runs to the 0V injector lead on cylinder 1.

The 12V power is t-connected off the radio lead behind my aftermarket Panasonic head unit.

When I attached the wiring to the mpguino as per the printing on the board, the mpguino lit up appropriately with the ignition in. Problem was, there was no instant economy data and the idle on the engine was off. The idle hunted up and down and the car behaved as if a cylinder was randomly misfiring. And checking with a code reader on the obd port, sure enough, there was a random cylinder misfire. And the screen flickered at a very high rate of speed, but I thought this was the design.

Upon unplugging the mpguino, the engine returned to normal.

I think the issue is a miswiring of the mpguino. I had double checked there was no shorting of the injector lead and it was behaving fine.

The printing on the board lists this from top to bottom (with the buttons to the upper left, facing the back)

12V
I
(blank)
-

This I figured to be 12V, injector , VSS, -ve

On the official mpguino website (the opengauge one, apparently I don't have enough posts to post links!)

The wiring diagram is different, showing (VSS, 12V, INJ, GND). Is this correct? The version there is 1.1.

Thanks!!

PS, I have v1.3 of mpguino

[dcb]

The pinout shown here is the same for 1.1 and 1.3. Also note that thick wire isn't necessary, and I can appreciate how much the crimp plug is a pain in the butt, been wanting to do something about that for a while. They are tested before being shipped though, so it is likely something about the wiring.

[gone.st]

Thanks for the reply!

Just before you posted, I decided to bite the bullet since the tracings seemed to match between v1.1 and v1.3. I guess force of habit I trust the PCB printing of labels more than the instructions online (had a bad experience once before!)

Anyways, wired it up properly stealing a floppy plug from an old PSU, found the VSS (btws, for 2004-2005 [maybe more] Toyota Echo drivers, it's Plug 3 from the left on the ECU, Violet/White wire)

Lit up perfectly this time! Had fun testing it out. Calibration to come.

I chose the heavier gauge wire for mechanical strength and the wire I was using had solid insulation which I wanted to use since it was going to take a fair bit of hot/cold in the engine compartment. I would hate for the insulation to fail, shorting the injector lead to ground and misfiring the cylinder

[dcb]

That's good news, thanks for the followup!