Power FC FD3S fuel resistor relay.
06-29-16, 01:48 PM
#1
Full Member
Thread Starter
FD3S fuel resistor relay.
Guys is it ok to unplug this and leave it unplugged if your running a power FC, and you've done the 12v relay mod to the fuel pump? Or do the wires still need to be grounded/bypassed etc
07-01-16, 06:17 AM
#4
Full Member
Thread Starter
07-03-16, 10:15 AM
#6
Full Member
Thread Starter
When we mod for power this isn't our friend as lower voltage to the pump under harsh loads (if anything went wrong) could lean out the system.
My query was if running a power FC and the pump off its own 12v source would this resistor relay be able to be left unplugged as technically it shouldn't work if not running factory Ecu. I might unplug it and see what happens. If it runs crappy I'll jump it like banzai boys said.
07-03-16, 11:13 AM
#7
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,854
Received 2,616 Likes
on
1,853 Posts
From what I understand it was added by Mazda to try save fuel to make the rotary a little more economical. So at idle the the resistor relay will limit the voltage sent to the pump on idle for example so it doesn't flow at max (which would be 12v) to save on fuel. As engine load increases so would the voltage to the pump supplying fuel faster.
When we mod for power this isn't our friend as lower voltage to the pump under harsh loads (if anything went wrong) could lean out the system.
My query was if running a power FC and the pump off its own 12v source would this resistor relay be able to be left unplugged as technically it shouldn't work if not running factory Ecu. I might unplug it and see what happens. If it runs crappy I'll jump it like banzai boys said.
When we mod for power this isn't our friend as lower voltage to the pump under harsh loads (if anything went wrong) could lean out the system.
My query was if running a power FC and the pump off its own 12v source would this resistor relay be able to be left unplugged as technically it shouldn't work if not running factory Ecu. I might unplug it and see what happens. If it runs crappy I'll jump it like banzai boys said.
Mazda has this system set up so that under 1psi of boost, the fuel pump is running on ~9v. since fuel demand is low, this has no effect on fuel economy, as fuel pressure stays the same. what it does do, is make the fuel pump quieter, they say it lasts longer, but more importantly is that you're not heating up the fuel by pumping it around the car at full stream all the time.
secondly the default for this system in the FD is 12V to the pump, the relay has to switch ON to go through the resistor.
if you do a little searching a lot of the high HP guys are actually putting this back on their cars...
Trending Topics
07-04-16, 01:54 PM
#8
Full Member
Thread Starter
couple of minor corrections.
Mazda has this system set up so that under 1psi of boost, the fuel pump is running on ~9v. since fuel demand is low, this has no effect on fuel economy, as fuel pressure stays the same. what it does do, is make the fuel pump quieter, they say it lasts longer, but more importantly is that you're not heating up the fuel by pumping it around the car at full stream all the time.
secondly the default for this system in the FD is 12V to the pump, the relay has to switch ON to go through the resistor.
if you do a little searching a lot of the high HP guys are actually putting this back on their cars...
Mazda has this system set up so that under 1psi of boost, the fuel pump is running on ~9v. since fuel demand is low, this has no effect on fuel economy, as fuel pressure stays the same. what it does do, is make the fuel pump quieter, they say it lasts longer, but more importantly is that you're not heating up the fuel by pumping it around the car at full stream all the time.
secondly the default for this system in the FD is 12V to the pump, the relay has to switch ON to go through the resistor.
if you do a little searching a lot of the high HP guys are actually putting this back on their cars...
Thread
Thread Starter
Forum
Replies
Last Post
TimWilbers
1st Generation Specific (1979-1985)
20
04-10-16 06:42 PM