[JohnB]

Hello.

I have the Speeduino 0.4.3c board and i'm experiencing a little confusion which would look like a rookie question.

I have a Delco ITMS-6F ECU and i'm trying to tap speeduino injector output into the stock harness and i have a question as unfortunately i can only get ahold of generic wiring documentation for Speeduino and not v0.4 board specific.

So the question is:

I have 8 pins on the Speeduino harness i've made:
Injector 1,2,3,4 and all are 1/2 and 2/2 of each output.

I plan to use paired high Z injectors, Inj 1 with 4 and 2 with 3 for a 4 cylinder setup.

A) What is the polarity of the pins 1/2 and 2/2 of Speeduino 0.4v board?

Since i see Speeduino injectors normally wired one side permanently to fused +12v as per the manual, should i assume one of the 1/2 or 2/2 output +12v within the board? Or are just extra outputs of the same channel?

B) For a 4 Injector setup with 2 pairs, what is the wiring on 0.4.3c?

Do i use it as:
-Inj1 1/2 -----> Injector 1&4 pin 1

-Inj1 2/2------> Paralleled with Inj2 2/2 and to Injector 1&4 + 2&3 pin 2

-Inj2 1/2------> Injector 2&3 pin 1

-Inj2 2/2------> Paralleled with Inj1 2/2 and Injector 2&3 + 1&4 pin 2
The above with whatever polarity is correct as i have absolutely no idea.

Or do i use it as:
Taking Inj1 1/2 and Inj2 1/2 and using them for each injector pair's pin 1 and wire pin 2 to fused +12v?

One of the above combinations is wrong and obviously releases blue smoke so i need to figure out what's going on.

Thanks in advance.

[jonbill]

The generic wiring diagrams apply to 0.4.3.
The injector outputs are grounding and there are two pins per channel just to carry higher load than a single trace can handle.
So you wire both pins of the channel to -ve of both injectors and the the other side of the injectors to ign switched +ve.
Apols for brevity

[JohnB]

Short and simple reply, that's what i needed! Thank you very much.

So i'll continue as following:

Inj1
1/2 + 2/2 ----> Injector 1&4 Pin 1

Inj2
1/2 + 2/2 -----> Injector 2&3 Pin 1

Pin 2 of all Injectors ----> +12v fused Ign as usually.

Btw things can get complicated with using stock harnesses as mine sends positive pulse from the stock ECU to injector pairs and the other pin is grounded through an internal current limiting circuit, so i'll break the ground connection and use the wires as +12v and have the ex-stock-positive wires as -ve for Speeduino's injector outputs.

[jonbill]

yes - assuming firing order is 1,3,4,2

[JohnB]

Yes exactly, it's a GM Family 1 engine, the A13SMS - C14SE variant with 1-3-4-2, so that works.

Thank you very much for your input.