I'm wondering what the poliarity is on the seconday injectors wires. Anybody know what wire is + and -??

 

 

One wire is solid black with yellow strip
The other wire is solid green with black stripe.

 

http://www.iluvmyrx7.com/3rd_gen_manuals.htm

Look through service manuals; (good idea to download them if you have space or print what you need) you will find schematics and other diagrams

BLK/Yellow is common
Green/BLK is injector specific

Thats from memory when I did mine. So look at manuals to make sure.

Blk/Yellow are on all injectors; ( I believe that actually all spliced into one wire in the harness) then the other wire is different colors and receives ECU signal.

Hope that helps.

Also, I put the resistors on the inside of the car near the ECU plug. It was easier and cleaner cause I had wire harness was out the car.

 

I have the manual, I'm going to look for it.

 

I'm still confused. I have a black and red wire comming off the 1600 injector. What wolour would I hook it up to on the injector clip?

 

As long as you have the wires paired correctly coming from the ECU, I don't think it matters as to which of the two wires gets connected to which lead on a single injector.

 

The common wire is probably + (connect red injector wire to BLK/yellow). But I don't think it matters so long as you hook both wires up. Anyone know for sure if the polarity matters?

-Max

 

I am assuming that you are installing new clips correct?
If you are, it is easier than you think.

Just match up the clips. There is a notch inside the clip so you cannot install it upside down. Look at the stock clip see where the notch is, take new clip line it the same way and youll see where the wires go.

Thats it.

It does matter, you can install them backwards ( I learned the hard way and I am not going there)

I will rephrase what I said earlier:

BLK/Yellow is a ground. All four injectors have this color coded wire. All four of which come together (spliced) and go to a ground through the ECU.

Each injector then has a different colored wire that goes all the way to the ECU.

I will look through the manuals to find the schematics to show you this.

 

I don't think polarity matters...or I just got real lucky.

 

OK here we go

Page F-225
http://www.iluvmyrx7.com/3rd_gen_manuals.htm

In this diagram in the upper left that each BLK/Yellow wire is spliced together and go to EGI Main Relay. (Just a ground)
Also if you follow the injector "colored" wires, each goes to the ECU plug #4
At the bottom of the diagram shows each injector clip. Labeled B15-B18

Now notice that all 4 have the BLK/Yellow on the same side. Use you other injectors as a reference. The new clip should have same notch along with new injector.

Hopefully that answers some questions.

 

That was awesome, you deserve a trophy for that!
And thanks to everyone else who help too.

 

Polarity on a single injector is irrelevant. They are solenoids. When there's current through them, they open.

 

I think the common wire is +12v, not ground. But I still suspect that you could swap the wires on an injector and it wouldn't affect its operation, so I don't think it matters.

-Max

 

fwiw the b/y is the 12v source and the lg/r, lg/b,lg/w,lg are the ground ecu controlled side

 

Polarity does not matter

 

Well I find out real soon

 

1sicsol,

I hate to invade your thread with my problems, but is there anyway you could do me a huge favor? I am treading a similiar path as you, not upgrading injectors but understanding how they are to recieve power. And since, or if you still have your Im off, is there any way you could test power supply to your injectors for me?

I'm needing to know if your secondary injectors both front and rear are recieving power when the ignition is on from the colored wire that comes from the ecu (not the b/y wire). And if your primary injectors are recieving 0v from the colored wires that come from your ecu as well. If not I can understand, and thank you anyways.

 

Well I unpluged my secondary injectors once when the car was idling and it did nothing.

The car runs off the primary injectors at idle then uses secondary after 4000rpm and or when in boost (i believe)

Also I cannot start the car with out the UIM on so it would be hard to test that way.

So to try and answer you the secondary injectors recieve no power at idle and the primarys are recieving power at idle.

 

pimpin7, the injectors get +12v when the key is on. I'm not precisely sure what key positions give +12v, but I hope you get the idea that the +12v is constantly available. The ECU controls the "ground" side of the circuit. To fire the injector, the ECU grounds the colored injector wire. That makes a circuit and current flows through the injector, causing it to open.

This is somewhat unituitive, since it is natural to think of the ground being common, and the +12v being "switched". But that isn't how they work -- it is the ground side that is "switched".

Electrical current in general is somewhat counter-intuitive, since the electrons flow from the negative to the positive, and not the other way around.

-Max

 

Max:

Your right, that is my problem the way the grounding work is backwards of what I think when I think of how positive and negative work to power a source.

1sicsol:

Sorry for the confusion. I was referring to when the ignition is turned to the "ON" position. Not cranked over to start the car or when the car is running. I am confused with the injectors because it seems well at least mine anyways is that the secondaries recieve their power differntly from the primaries.

When I did testing of my injectors the Secondaries are always recieving power whether in the "ON" position or cranked over at both the b/y wire and also the wire that connects to the ecu. The primaries apperantly recieve power different in that the b/y is always powered, but the wire that runs from the ecu reads 0v in the "ON" position, but when I tested it with the B+ while cranking it over the volts changed it didn't stay at 0v and it worked its way up from 0v to the 12v. Is that right? Mad7ist told me that this was supposed to happen when I cranked the engine and testbut why doesn't the secondaries work like this, if they run off the same system.

That is what I'm trying to figure out if those readings are correct, when the key is the in the "ON" position.

 

So in my backwardsness it would be that my injectors are recieving voltage properly.

So the primaries are being grounded to let the injectors open. But the secondaries are recieving two + at the wires to keep the injectors closed????????? Until at a precise rpm or boost it well then ground those injectors so they will open?

 

The injector stays closed until you run current through it. It has a spring or something that keeps it closed. Electricity doesn't do anything (for the most part) without a circuit. Having +12v on one injector terminal and no signal on the other terminal is essentially the same as having nothing connected to it. The injector will stay closed until you make a circuit, and the constant +12v doesn't have anything to do with them staying closed (it doesn't "hold" the injector closed).

The ECU uses only the primary injectors at idle and at low RPMs and light loads. At some point, it phases the secondaries in. After the phase-in, both the primary and secondary injectors are firing (i.e. it doesn't stop firing the primaries after the secondaries are phased in). There is no fixed RPM at which this phase-in occurs. I think it technically happens when the duty cycle on the primary injectors reaches 40% or so. The duty cycle of the primary injectors depends on air temp, RPM, manifold pressure, fuel maps, etc. -- all the stuff the ECU uses to decide how much fuel to deliver. So you can't nail it down to a single variable like "when manifold pressure goes positive" or "at 3800 RPM". This variability is the reason you can run large secondaries with the stock ECU and a piggyback computer (e.g. the S-AFC).

Also, the ECU doesn't just switch on the injectors by providing a constant ground. It switches the injectors on and off for a very specific amount of time for each rotation of the eccentric shaft. If you need 5 milliseconds of fuel from the primary injectors at idle, the ECU will provide a ground for the primary injectors for only 5 milliseconds to deliver just the right amount of fuel. It will leave the injectors closed for the rest of the time by not providing a ground.

-Max

 

Boy they make cars so darn complicated these days, I remember when on my grandpa's car all we had to do was crank the engine.

 

Max, seriously thanks for the information I am slowly getting the big picture of how the injectors work on our cars, that is some good stuff, can't thank you enough for the enlightenment.