Reveresed fuel flow Questions - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

hockeyrules · 11-02-2012, 03:08 PM

Alright so I had a new fuel setup installed, "professionally done". Areomotive FPR, injector dynamics 725cc, tune, and a top feed rail.

So I have been having problems with idleing and various other issues I have been trying to trouble shoot.

I noticed my FPR is on the other end of my fuel rail, but the lines are still going to the correct fuel lines.

My question is would the fuel running in the opposite directions through the rail affect anything?

cotbu · 11-02-2012, 04:48 PM

This is how the fuel flows, if you were to send fuel in though the fuel pressure regulator, you will have idling problems, bucking problems, etc. I can't really tell you because I would never do that intentionally.

Now, if you mean the fuel enters the rail from the front as opposed to the rear? no that wouldn't cause problems per say.

AsleepAltima · 11-02-2012, 04:52 PM

a friend of mine that builds engines couldnt understand why we said the fpr was last in the system... he couldnt understand how it would create pressure if it was last and not first. that diagram would have been nice to show him lol.

cotbu · 11-02-2012, 05:23 PM

I got this picture from a local forum where I edited it for that thread, that's why the fpr doesn't have in and out, but they argued the same thing, so much I started to doubt myself. I'm still not sure. lol!

ultimateirving · 11-02-2012, 05:28 PM

Easiest way to explain it, the pressure builds up BEFORE the regulator, and as the regulator opens it relieves the pressure. So as long as the fuel is flowing thru the rail, and into the regulator it does not matter that the regulator is in the rear.

AsleepAltima · 11-02-2012, 05:59 PM

the easiest way to describe it as that it creates a restriction in the system. by being after the rail, it builds up the pressure in the rail and creates more pressure for the injectors. my buddy understood it after that.

AsleepAltima · 11-02-2012, 06:05 PM

which is basically what ultimate said

smartoss · 11-02-2012, 06:22 PM

Like they said above it shouldn't matter what side of the rail the FPR is on; as long as you have the Feed and return lines hooked up correctly.

Are you able to verify the Fuel pressure? I know when I first installed my Tomei FPR the pressure was set to low and the car wouldn't hold an idle. Once I got it set to 3 bar with the vacuum line off it was good to go.

11-02-2012, 03:08 PM	#1
hockeyrules Zilvia Junkie Join Date: Oct 2009 Location: Peoria, az Posts: 523 Trader Rating: (15) Feedback Score: 15 reviews	Reveresed fuel flow Questions Alright so I had a new fuel setup installed, "professionally done". Areomotive FPR, injector dynamics 725cc, tune, and a top feed rail. So I have been having problems with idleing and various other issues I have been trying to trouble shoot. I noticed my FPR is on the other end of my fuel rail, but the lines are still going to the correct fuel lines. My question is would the fuel running in the opposite directions through the rail affect anything?

11-02-2012, 04:48 PM	#2
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	This is how the fuel flows, if you were to send fuel in though the fuel pressure regulator, you will have idling problems, bucking problems, etc. I can't really tell you because I would never do that intentionally. Now, if you mean the fuel enters the rail from the front as opposed to the rear? no that wouldn't cause problems per say. __________________ LoverTechnologies "Half Broken Things!"

11-02-2012, 05:23 PM	#4
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	I got this picture from a local forum where I edited it for that thread, that's why the fpr doesn't have in and out, but they argued the same thing, so much I started to doubt myself. I'm still not sure. lol! __________________ LoverTechnologies "Half Broken Things!"

11-02-2012, 05:28 PM	#5
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 33 Posts: 1,519 Trader Rating: (1) Feedback Score: 1 reviews	Easiest way to explain it, the pressure builds up BEFORE the regulator, and as the regulator opens it relieves the pressure. So as long as the fuel is flowing thru the rail, and into the regulator it does not matter that the regulator is in the rear. __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

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11-02-2012, 04:52 PM	#3
AsleepAltima Zilvia Addict Join Date: Aug 2006 Location: Ontario, Ca Age: 48 Posts: 667 Trader Rating: (8) Feedback Score: 8 reviews	a friend of mine that builds engines couldnt understand why we said the fpr was last in the system... he couldnt understand how it would create pressure if it was last and not first. that diagram would have been nice to show him lol.

11-02-2012, 05:59 PM	#6
AsleepAltima Zilvia Addict Join Date: Aug 2006 Location: Ontario, Ca Age: 48 Posts: 667 Trader Rating: (8) Feedback Score: 8 reviews	the easiest way to describe it as that it creates a restriction in the system. by being after the rail, it builds up the pressure in the rail and creates more pressure for the injectors. my buddy understood it after that.

11-02-2012, 06:05 PM	#7
AsleepAltima Zilvia Addict Join Date: Aug 2006 Location: Ontario, Ca Age: 48 Posts: 667 Trader Rating: (8) Feedback Score: 8 reviews	which is basically what ultimate said

11-02-2012, 06:22 PM	#8
smartoss Leaky Injector Join Date: Jul 2011 Location: Brainerd MN Age: 34 Posts: 101 Trader Rating: (8) Feedback Score: 8 reviews	Like they said above it shouldn't matter what side of the rail the FPR is on; as long as you have the Feed and return lines hooked up correctly. Are you able to verify the Fuel pressure? I know when I first installed my Tomei FPR the pressure was set to low and the car wouldn't hold an idle. Once I got it set to 3 bar with the vacuum line off it was good to go.