alright. . . does anybody have any clues as to how i could add one fuel injector to the wiring on my FD successfully? the ecu has to read "x" amount of ohms for all the injectors. . . so i need to add one while still being within that limit. . . lemme know if you have any ideas.


thanks,
paul

 

Sorry, I've never heard of anyone successfully adding another injector to the stock harness and getting the stock ECU to fire it along with the others.

All the conversions I've seen either added 2 additional injectors in the intake elbow (GReddy), or welded additional injector bungs into the dip in the top of the upper intake manifold, and were controlled by an additional injector controller (HKS AIC) or a stand-alone engine management system (Motec, etc.).

Here's a picture of Kevin Wyum's setup driven by a (at that time, anyway) Motec M4...

 

jim. . . im happy to hear from "you". . . im not talking about adding the injector in the stock location or anything. . . just had to clear that up. im really wanting to do "this" w/o having an additional injector controller. i know the ecu has to read a certain amount of resistance in order for its calculations to be correct. i was thinking about upgrading to 1680s and instead of using restrictors i would use the additional injector to bring the "total" resistance up. . . the problem is that i dont really wanna mess re-doing my fuel system at the moment. . . just got this thing running. i had heard that the power fc (using datalogit) had the ability to control the resistance. . . is this true? . . . and am i spelling resistance wrong?. . . maybe its resistence. . . whateva!!! haha. . . thanks a lot, jim.

paul

 

Part # Part Description Price (US$)
FL3700F5 Haltech F5 Fuel Computer $360
FL370008 GReddy Rebic III $702
FL375009 GReddy Rebic Simulator $315
FL370512 GReddy Additional Injector Harness $16.36
FL370011 GReddy Additional Injector Driver Harness $198


from rx7.com

you need an additional controler for it

 

thanks skunks. . . i guess. . . you sure are a big help. . . DUUUUUUUUUUUUUUDE. . . . sarcasm. . . maybe i need an additional controller for that.

paul

 

Really, a resistor in-line with the low impedance injectors is the best way to approach the problem. If you add an additional fuel injector to get the resistance to where the ECU wants to see it, even if that's possible you won't have any clean way of controlling it.

The early 2nd gens all had resistor packs - the ECU was designed to drive high impedance injectors, they put in low and had a resistor pack to up the resistance the ECU sees. It's not like this is a hack - this is really common on numerous vehicles, I think even some Hondas use resistor packs.

Anyhow, truck down to Radio Shack and buy some 10 ohm 10 watt resistors. Splice it into one of the wires going into a low impedance injector (do it for each low impedance injector you've got) and you're done. Doesn't matter which wire you tap it into, either.

I've run a number of high output 2nd gens like this for YEARS with no problems. Just make sure the electrical connection is good!

I seriously doubt you can alter the resistance the PowerFC works with - that's a pretty low-level hardware thing. You've got the best situation - if you had an ECU that only worked with low impedance injectors, you couldn't run high impedance. A high impedance ECU can work with either.

Dale

 

thanks dale!!!! the computer will be controlling the injector. the injector is gonna be "tied" into the secondary injector harness and therefore controlled by that existing setup. so having three injectors in that circuit might be a problem. . . actually with the 10 ohm resister inline with the additional fuel injector it might work. . . it shouldnt mess with what the other injectors read as far as resistance unless the stockers read under 10 ohm. . . . which we know isnt true. guess ill be trying this here soon. . . ill let you guys know how this works when i get it done.

paul

 

You could probably poor-boy and control your additional injector with a MegaSquirt running piggyback.


http://www.bgsoflex.com/megasquirt.html