B6t injector loom wiring? what wires go where?

[AmmoJammo]

So I'm in the process of Megasquirting my B6t engine.
I can't figure out what all the wires in the injector loom do...



The four yellow wires to the right splice into two wires, and run back to the ecu... I assume these are the injector signals.

The four blue wires taped in a bunch run to the resistor pack (positive feed for the injectors)

The green wire runs in the direction of the ECU, where it finds a relay, which I had spliced a wire into, and was running the fuel pump from this.. I assume this is a wire that only has +12volts on it when the engine is running.. as this is what I was using it for? Is this what its meant to be?!

The two blue wire/yellow trace wires splice together, then go to the TPS... on their way back to the ecu, the wire is then spliced again, and runs to the air flow meter... This appears to be one end of the temperature sensor...

blue/red trace splice together as well, and run straight back to the ecu.. I believe the other end of the temp sensor...

And finally, the black wire, splices into a hand full of other black wires (I assume its a ground... it connects to the shield on a few shielded wires too)

BUT!
In the loom on the engine itself, there's a two conductor loom that runs down somewhere behind the engine... I thought this was the IAC valve... but what wires go to it?

On another note, why would there be a ground, and +12volt feed to the injector loom anyway? I measure 40ohms across these two wires (black and green in the picture)

Across the two wires that I concluded where the temp sensor, I measured 2.7k (which is in spec for the thermo sensor, at the current ambient temperature)

Any help would be fantastic!

Thanks!

[Rocketman]

The injectors get +12v on one side and this stays constant. The ECU grounds the two injector legs intermittently to fire them.
There's going to be a vref on the TPS, and then a signal wire. Vref might be +5v im not exactly sure but the VAF also uses a vref.

Theres also the Idle valve wiring, and then the ECU temp sensor in the bottom of the intake manifold.

What donor did your loom come from? Dont think the B6T used resistor packs.

[AmmoJammo]

Its a jap spec early version B6t... however, the old ecu was from a newer 4wd engine..
And its a mess! and half the reason I'm megasquirting it...

It has the resistor packs as mentioned, as they are low impedance injectors, and the ecu shouldn't/couldn't directly drive them

Someone said this loom should include the idle valve wiring... but I just don't see it...

[AmmoJammo]

14 wires..
As far as I can tell..

black - ground (to where? I don't know..)

green/red - 12v (to where? I don't know..)

blue/yellow x2 - thermo sensor (joined together)

blue/red x 2 - thermo sensor (joined together)

yellow/black x 2 - injector bank1 (joined together)

yellow x2 - injector bank2 (joined together)

blue/black - injector 1 12volt

blue/yellow - injector 2 12volt

blue/red - injector 3 12volt

blue/white - injector 4 12volt

[AmmoJammo]

Here's the wires I have, looking from the back of the plug (that used to be connected to the engine loom)

black - ground
yellow/black - injector A from ecu (joined to the other yellow/black)
yellow - injector B from ecu (joined to the other yellow)
blue/black - injector 1 12volt
blue/yellow - injector 2 12volt
blue/red - injector 3 12volt
blue/white - injector 4 12volt
lightblue/yellow - thermo sensor (joined to the other LB/Y)
lightblue/red - thermo sensor (joined to the other LB/R)
green/red - 12volts when engine running

I'm lost?

[Rocketman]

Are you not using the rest of the loom?

[AmmoJammo]

The original loom is completely hacked up.

I'm replacing the stock ecu, with a Megasquirt, and making a new engine loom from scratch.
The only connector I need to use from the original loom, is the connector for the injector harness.

[AmmoJammo]

Does anyone have an injector loom (preferably off an engine) that they can check where the idle control valve connections go in the injector harness plug? Or even what colours they are?

I just can't figure this out :/

Oh, and this webpage with someone elses pics that has come in handy for me in the past

http://www.werbatfik.com/jdmintake.htm

[Rocketman]

Is it possible to forgo that connector? and get a universal one? There seems to be a lot of redundant wiring running through it.

I never was able to get MS to work with the stock idle valve either, but then again I didn't really put a ton of effort into it.

Ya, that's my page & pictures there. I have the manifold still but I have no idea where the harness is. I think I ended up using a USDM injector harness on that manifold. Glad they've been helpful.

[AmmoJammo]

In my situation, there isn't really any redundant wiring

I want to run the eight wires total for the injectors, as I'm using fairly thin wire, so don't want to splice them together.

Also, I plan to use the thermo sensor for the Megasquirt, assuming its suitable?

What idle valve did you end up using? I liked the fact that the wiring for it was in the same connector!

[Rocketman]

I ended up using the mechanical/coolant fast idle valve portion, I didn't run any electronic idle control. Didn't really have any issues but if I did it again I'd just use a GM or other PWM idle valve.

The Mazda/Ford thermo sensor works but the GM one available, IIRC, has a higher resolution so you get a more accurate temp reading in the ECU.
You could run one large power wire for the injectors, and then the individual grounds to the injector drivers. Even the stock ECU bundled the power and grounds together, they're batch fire, two fire at a time.

If you're really hell bent on using that there, try matching up with the ECU pinout

[AmmoJammo]

Where does the idle valve connect at the ECU?

I actually had a 4wd, newer model ecu, on a 2wd, older engine, running a switch type tps, rather than a variable (and it probably explains why my afrs would randomly go wack)

[AmmoJammo]

Is the idle valve on this diagram? or is this diagram not applicable...

[Rocketman]

Yeah it's there, still off pin 2Q. Shows up as "Idle Up" solenoid. The JDM valve might just be an on/off fast idle valve which isn't really what you want

[AmmoJammo]

Yeah it's there, still off pin 2Q. Shows up as "Idle Up" solenoid. The JDM valve might just be an on/off fast idle valve which isn't really what you want

But that isn't shown as going through the B22 connector (the injector loom connector)