How will I install Denso 720cc secondaries on S5 Turbo II?
 

I bought new injectors cause my old ones were bad.
2x 550cc RC Eng for primaries and 2x 720cc Denso secondaries from RX-7.com.
With the 720's I also got 2 connectors and 2 resistors.
What is the installing procedure?

-Fanis

Remove upper intake, remove old secondaries, install new secondaries.

You got the resistors because these are high impedance injectors. If you were installing into an '86-'87.5, you would need the resistors. Since you car is already set up for high impedance, you don't need the resistors.

Also, you're going to need something to tune those injectors (like an S-AFC).

You got it backwards, Aaron. The 720's are most likely LOW impedance injectors, and will need the resistor on the car in question.

550's are about as big as they commonly make high impedance injectors.

Dale

***IF using LI injectors on a HI harness, you must splice into the harness, at each injector lead (for a total of 4) 10 ohm/10watt resistors available at radio shack for a couple of bucks. Doesn't matter which wire of the 2 per injector you splice to, polarity isn't an issue here. This bumps the LI resistance up to acceptable load for the ECU to see.

The invoice said the 720's were low impedance injectors...
Thanks to MrFuzzy I found my answer here.
http://www.rotaryresurrection.com/ro.../injector.html


-Fanis

Where could i find a how-to with images for this modification?

-Fanis

where is the best or easiest place to splice in the resistors?..JET

Oops... :) Well, if it counts for anything, I had it right in my head...Translation between brain and hands not working... :)

Put them in the plugs just before the injectors. There is a wire (I think black w/yellow) that is constant 12V. That's the best place.

.

Here is a quote for Jahoo88 that i found while searching the forum.
Well which one is it? Black w/yellow or green wire?
(Thank God we are not disarming a bomb!!!)

-Fanis

bump
Please people I need an aswer on this.

I could use a pic have 2 of them thing on my desk =P

It doesn't matter what wire you use. Injectors are non-polar. They're just a solenoid. I just like to keep it consistant.

2 resistors on one wire per plug?

i thought all s4 's were low impedence ...

when i had to replace one of my injectors oh my 88TII i got it from victoria british, and they sent me a Low Impedence, and i havent had any problems

if it was of the wrong impedence ... what symptoms would i notice?

you would notice :)

rough idle? fried ecu?

There was a change in injector impedance by Mazda around the midlife of the FC. Early FC's have LI but late FC's have HI.

So when I cut the old connector out to install the new connector it doesn't matter how I connect the wires, as long as they are connected well.
O.k. So how do I connect the resistors?

-Fanis

IMO the best place is at the ECU. No engine heat, no engine vibration. :)

No offense, but if you don't know how to install a resistor into a wire, then you should get someone with a bit of automotive electrical experience to do this for you. This needs to be done right.

No offence taken.
The RX-7 is not a playground so I PLAY the stupid guy in order to get a complete and right answer. Automotive electrical is not what I do for a living but I no beginner and a fast learner. I am getting different answers on what colour the constant 12V is.(you can read this in the earlier posts) Aaron Cake thinks its the black w/yellow and Yahoo88 the green wire.
Could someone that has experience on this, give me a straightforward answer? Can u help me NZConvertible? I liked the near the ecu idea.

I doesn't matter WHAT wire you put the resistor in. Electrically, it is equivelant. The injectors are non-polar. Connect them any way you feel like.

So the conclusion is that it doesn't matter how you connect the connectors and it doesn't matter how you connect the resistors.
If the above stands, the process is not something really difficult.

Correct.

Bless you my son!!!
I'll try to take some photos of the installation and post it here when I'll do it.

-Fanis

It may be, but then you may have more work if you also have to change the injector conncector from the later oval style to the rectangular bosch style. In that case it's just easier to add the resistor along with the connector change.

Have a look at the ECU wiring diagram and it will all become clearer. One wire from the main relay splits into four seperate wires to feed 12V to each injector. The other wire from each injector goes to the ECU.

If you install the resistors at the injectors, you can install them into either of the injector's two wires for the same effect. Alternatively locate the four injector wires at the ECU (using the wiring diagram) and install the resistors there. :)