so i may be needing some help. ive got the wiring diagram for the ecu harness so that wont be too bad. but i have 4 high impedence injectors that i plan on running on an s4 ecu (unless someone wants to trade my highs for your lows) and i know you can do this with something but cant think of the name of them. how would i go about doing this?

plus how do i rewire an s5 afm to fit on an s4? more questions to come.

 

Why would you want to? The s5 AFM is more restrictive than the s4.... And you wire in resistors. 10 watt, 10 ohm resistors on the injector leads @ the ecu. Don't wire them under the hood, too much heat.

 

ok if somone wants to trade me an s4 afm for an s5 afm then i wont complain but i know it is more restrictive. i have a brand new nice s5 wiring harness and had an s5 t2 ecu that i was going to conver everything over to s5 under the hood but i decided not to. so i sold the s4 afm like a dumass. now i need to either 1) rewire the s5 afm to fit the s4 or get an s4. since i am kinda broke at the moment. ill do the rewire. unless somone wants to be kind

where can i get resistors? (i already have two) i need 2 more

 

radioshack sells them. They're about 2.5" long or so, ceramic. As for the AFM, I know it was done in the past, I want to say Landers (hypntyz7) was the one who did it, I'll search and see what I can find since I think I replied to that thread, or even saved the diagram.

 

woohoo more diagrams.

 

resistor correct?

 

Yes, that is a resistor. I'm not to trust of the connections (i prefer soldering them in) But whatever works I guess.

 

i didnt do that. i think a retarded money got ahold of my wiring harness. its horrible

btw i have no emissions, ac, or ps what can i cut from the ecu harness to clean up the clutter?

 

Woohoo, found it.

 

time for me to look at a new afm. thats too much stuff. thanks. i may try it out. maybe..

 

All that searching for nothing!

 

no i may use it.

 

Wait a minute- I thought you NEEDED high-impedance injectors for a S4 ECU (after 87 1/2)????
What am I missing here?

 

nope. low for 87. its the 88 up the had high.

 

My bad- thought you had an '88

 

Actually, this is all screwed up. You use resistors to increase the resistance on low impedance injectors to the 12-13ohm range. You don't need to wire in resistors for high impedance injectors, ever. If you have an older harness that came with low impedance injectors. You just loop the wires at the resistor pack that goes on the passanger strut tower. You don't need resistors.

 

Inector Information
Mazda RX-7(Gen 1 and 2) Fuel injector identification guide
(Note that some injectors carry the same part number as others but plug styles and resistances can vary. Low impedance refers to 2-3 ohms, high impedance refers to 12-13 ohms.)


Year type impedance plug style plug notch position flow rating color part number
84-85 13B NT low square center 680cc orange 195500-0900
86-87 13B NT low square center 460cc red 195500-1350
86-87 13B T low square center 550cc tan 195500-1370
88 13B NT high square offset 460cc purple 195500-1350
88 13b T high square offset 550cc purple 195500-1370
89-91 13B NT high oval center 460cc red 195500-2010
89-91 13B T high oval center 550cc purple 195500-2020


As a side note, replacement fuel injector clips(for wiring harness) can be obtained from auto parts stores to replace broken stock clips. I got the parts from autozone:
GP Sorenson part 800-9416 Fuel Injector Connector


More about injector impedances on 2nd generations:
1986 and 1987 model cars used low impedance(2-3 ohm) injectors. Low impedance injectors have a center notch on the plug. The wiring harness used with LI injectors integrates an injector resistor pack, wired inline between the ECU and injectors(under stock air box) to bump overall load seen at the ECU to 12-13 ohms.
1988 and later models used high impedance injectors. 1988 HI injectors have an offset notch on the plug, and all post 1988 injectors are HI with an oval plug(until 3rd generation side feed injectors which are totally different). The wiring harness on these models deleted the injector resistor pacl, carrying the 12-13 ohm load from the injectors directly to the computer.


When performing engine/wiring/injector swaps, the type of setup must be noted and kept together. This is easy as LI injectors will only plug into a harness meant for them(due to the position of the plug notch) and vice versa for HI injectors and harnesses. 88 and post 89 HI injectors and harnesses are not interchangeable.
A car that previously ran one type of setup can be changed to the other…keep the injectors and wiring harness together. The ECU will not know the difference.
It is also possible, but not necessarily recommended, to use HI injectors on a LI harness and vice versa:


***TO do so you must modify the injectors to fit the opposing wiring harness by taking off the notch on the plug.


***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.


***IF using HI injectors on a LI harness, you must unplug the resistor pack. Next, locate the supply wire in the center of 5 terminals. Bridge jumper wires from this terminal to each of the 4 outlying terminals, which basically completes the circuit without resistors, carrying the HI injectors' 12-13 ohm load directly to the ECU just as a HI harness would.

from kevin landers site.

 

Well, if you've got high impedance injectors, you either don't have to modify your harness at all. Or you simply have to jumper the wires at the resistor box as stated here:

***IF using HI injectors on a LI harness, you must unplug the resistor pack. Next, locate the supply wire in the center of 5 terminals. Bridge jumper wires from this terminal to each of the 4 outlying terminals, which basically completes the circuit without resistors, carrying the HI injectors' 12-13 ohm load directly to the ECU just as a HI harness would.

 

I have both the good afm and good injectors out of an '86 if you want to trade.

 

it needs to be a turbo afm and a 550 cc injectors.