Damn! What Can It Be? The Pfc?
Thread Starter
Senior Member
Joined: Feb 2002
Posts: 6,331
From: Frederick MD
Originally Posted by rxrotary2_7' date='Mar 4 2004, 06:31 AM
i understand "how" an injector works, what i dont (and obviously none of us here do) understand is WHY it works when the grounds are *jumped* together...
what i was getting at and now that i look at his diagram again is that the two injectors would complete a circut IF the grounds past the jumper were broken somewhere. something along these lines...
would the ecu complete the circut and fire them? this is where the individual drivers came into play in my mind... dont know if it is right or not, but i was just throwing it out there. that is also why i said that the he should find out the duty (like you said, and like i said you said) of the injector to see if they are at 100% or not....
best of luck figuring this out. i am to stupid to also.
what i was getting at and now that i look at his diagram again is that the two injectors would complete a circut IF the grounds past the jumper were broken somewhere. something along these lines...
would the ecu complete the circut and fire them? this is where the individual drivers came into play in my mind... dont know if it is right or not, but i was just throwing it out there. that is also why i said that the he should find out the duty (like you said, and like i said you said) of the injector to see if they are at 100% or not....
best of luck figuring this out. i am to stupid to also.
I just with the damn injectors didn't work at all.. cause I'm so baffled as to how that stupid jumper makes them work
You guys are great. I REALLY appreciate the time put in to helping me! Soon as I get off work, I'll start putting stuff back together so I can get you those duty numbers.. My roommate came home from Iraq last night, so I took some time away from the car.
So, my custom license plate will say: POS-13B
whaddya think? LOL
Thread Starter
Senior Member
Joined: Feb 2002
Posts: 6,331
From: Frederick MD
Originally Posted by FikseRxSeven' date='Mar 4 2004, 09:03 AM
POS-13B sounds about right..... lol
by jumping it...... wont each injector use the other as the ground? or it doesnt work that way?
by jumping it...... wont each injector use the other as the ground? or it doesnt work that way?
Senior Member
Joined: Sep 2003
Posts: 276
batch fire fuel injection setups will fire all the injectors off the same ground for the same duty cycle. mitsuis the ecu actually switches the batt voltage for a lot of sensors and stuff. on topic by running all the grounds together you will increase the voltage/amperage by reducing the resistance, vr6 mentioned this a while ago, even though the injectors ohm ok the need more juice than they are getting to fire. the ohm test mesures the resitance across the windings in the injector not the power required to move the injector pintle. jeff you are right about how the injector cycle and stuff works but rotary was saying that unlike the stock ecu, where each injector has a seperate pulsed and individualy controlled ground the pfc has one ground for all 4 that it pulses.
Senior Member
Joined: Nov 2002
Posts: 127
Originally Posted by tampaFD' date='Mar 4 2004, 07:10 AM
jeff you are right about how the injector cycle and stuff works but rotary was saying that unlike the stock ecu, where each injector has a seperate pulsed and individualy controlled ground the pfc has one ground for all 4 that it pulses.
I must be missing something.
Thread Starter
Senior Member
Joined: Feb 2002
Posts: 6,331
From: Frederick MD
Originally Posted by tampaFD' date='Mar 4 2004, 09:10 AM
unlike the stock ecu, where each injector has a seperate pulsed and individualy controlled ground the pfc has one ground for all 4 that it pulses.
I'm confused
Senior Member
Joined: Nov 2002
Posts: 127
Originally Posted by 9BASE3' date='Mar 4 2004, 07:56 AM
My only question is if there is one ground for all 4, how does it fire them at different times and not all at once? What determines the timing difference between the 2 primaries?
I'm confused
I'm confused
Here's a GUESS based on my basic understanding of the injector technology.
In batch fire modes, (multiport boingers most commonly) all the injectors have the same firing point (usually TDC compression). Bank fire systems split the firing points between banks (pairs, triplets or quads) and open one set of injectors at TDC of the compression stroke of piston 1 and the other set of injectors at TDC of the exhaust stroke of piston 1. These mixtures remains in the port until the intake valve opens.
If the RX7/PFC system is a batch fire or bank fire system there would be no need to have separate wires going to the separate connectors on the PFC. Since the intake ports on the front and rear chambers open at different times it would be almost impossible for a batch fire system to be at all efficient since you would be losing unburned fuel somewhere. So I gues we are left with either a sequential or batch fire system.
I will do some research and get back to you.
Thread Starter
Senior Member
Joined: Feb 2002
Posts: 6,331
From: Frederick MD
Originally Posted by jeff48920' date='Mar 4 2004, 10:33 AM
If the RX7/PFC system is a batch fire or bank fire system there would be no need to have separate wires going to the separate connectors on the PFC. Since the intake ports on the front and rear chambers open at different times it would be almost impossible for a batch fire system to be at all efficient since you would be losing unburned fuel somewhere. So I gues we are left with either a sequential or batch fire system.
I wonder though, at idle, would you even be able to tell if this situation was present? It didn't appear to be, however I'm not sure.
Senior Member
Joined: Nov 2002
Posts: 127
Since even in the stock ecu the secondaries don't begin to input until around 2750 RPM it would appear to me that only the primaries would fire. Therefore, if theis is the case with the PFC then only sequential or banked configurations are possible.
To add more confusion to the fire, try this link to a Haltech thread on the OTHER Forum
http://www.rx7club.com/showthread.php?s=&t...+fuel+injection
To add more confusion to the fire, try this link to a Haltech thread on the OTHER Forum
http://www.rx7club.com/showthread.php?s=&t...+fuel+injection