Greetings all!
In this write-up I will guide you on how to modify the Fuel Rail on your 4.7L engine. I will discuss two different ways to do this, one which is more cost effective and the other which better achieves the goals of this modification.
What are the goals of this modification you ask? They are twofold:
1. To decrease the amount of time fuel spends in the fuel rail. This lowers the total
temperature of fuel and reduces differences of temperatures between each injector.
2. Balance the flow and pressure of fuel among all the injectors.
This modification is based off the idea of another fellow who did this to his Dakota. You can find his write-up here and I credit him for coming up with this mod:
http://www.dakota-durango.com/forum/showthread.php?t=116570&page=3
He did research on the temperature of fuel, how it affects the efficiency of the engine, and Duner's Fuel Rail cooling. He came to the conclusion that it's not entirely fuel temperature that affects the engine's efficiency therefore cooling the fuel may not be the answer. Instead the temperature of the fuel at each injector needs to be uniform to allow similar combustion efficiency in each cylinder. This should increase efficiency and take some work away from the computer as it doesn't have to try to achieve an optimal fuel/air ratio in cylinders that are all burning differently.
After completing this mod I have noticed that my throttle response is a lot quicker and my Jeep has more power as it keeps pulling hard through each gear. I am still evaluating any increase in MPG but so far it looks like 1-3 extra MPG.
I wonder if the last cylinder in bank 2 is so problem prone because it's the last cylinder in the fuel rail and therefore it burns the hottest.
The two ways to do this are:
1. With two fuel rails. The one on your engine now (or another) and another from a junk
yard or wherever. You need two passenger side rails (this side has a 4AN pressure
test port that will be used as the new fuel input).
2. Using your existing (or an extra) fuel rail only. Doesn't provide quite the cooling and
efficiency of distribution of fuel. I HIGHLY recommend buying an extra rail to do
this as you could leave your engine disabled if something goes wrong.
Tools Needed:
-8mm socket for the fuel rail bolts
-10mm socket for the spark plug coils and resonator box
-Shop towels for cleaning up spilt gas and cleaning components
-Flat Head Screwdriver OR socket for hose clamps
-Access to a Vise
-Hack saw (or Dremel) with a good blade for metal cutting
-Masking Tape for marking where to cut the fuel rail
-EFI Fuel Rail Disconnect Tool, or in my case, a strip of plastic cut off an empty milk jug
-Valve Stem Core Remover (only needed for Mod 1)
Parts needed for either mod:
-6AN Push-Loc Hose Barb to 6AN female 90° Elbow (JEGS #110071)
-6AN Push-Loc Hose Barb to 6AN female straight (JEGS #110051)
-6AN Male to 5/16 Male Push-on EFI (JEGS #640930)
-6 Fuel Injection Hose Clamps (JEGS #16047, 10-pack)
-200+ grit sand paper
Parts needed strictly for Modification 1: (Push-Loc = Push-On = Twist-Loc)
-Fuel Rail off a 4.7L engine in good shape. Can be taken off a Dodge or a Jeep, should
be identical but check to make sure. I got one from a salvage yard for $50
-1 foot of 6AN push-loc (or twist-loc) hose (make sure it's safe for gasoline) (6AN = 3/8)
-2 feet of 4AN push-loc (or twist-loc) hose (make sure it's safe for gasoline) (4AN = 1/4)
-2 3/8" x 1" barbed hose plugs for capping off the cut crossover ends
-6AN x 4AN x 4AN all male y fitting (Got off EBay for $15)
-Two 45° 4AN Push-On Hose Barb to 4AN Female fittings (SUMMIT #MRG-P454)
-Two 120° 4AN Push-On Hose Barb to 4AN Female Fittings (SUMMIT #MRG-P1204)
Parts needed strictly for Modification 2: (Push-Loc = Push-On = Twist-Loc)
-2 feet of 6AN push-loc hose (make sure it's safe for gasoline) (6AN = 3/8)
-6AN x 6AN x 6AN all male Y-fitting (Got off EBay for $18)
-EFI Fuel Rail Fitting - 6AN Male to 5/16" Hard Line (JEGS #103100)
-6AN Flare Cap (JEGS #110312)
-Two 45° 6AN Push-Loc Hose Barb to 6AN Female fittings (JEGS #110061)
Pictures of the parts are below (I got the Y-Fittings off of Ebay for about $15 each):
Parts from JEGS:
Parts from SUMMIT
Hose Plugs (Got off Ebay)
Fuel Rail:
Let's get to it!
---------Dissasembly----------
-Remove the Fuel Pump Relay switch found in the fuse box under the hood. See Picture
-Start your engine, it will die after a few seconds. Then keep cranking until the engine no longer sputters. This releases the pressure in the Fuel System.
-Disconnect the negative terminal of your battery and isolate
-Remove your intake resonator and hose. Remove more if necessary to gain easy access to the fuel rail.
-Remove the 8 ignition coils from the engine. All the coils are the same so the order in which you reinstall them really doesn't matter. The nuts are 10mm in size. Keep in mind the location of the resistors and the grounding straps mounted on 4 of the coils. See picture below, there is a resistor and strap on either side of the engine.
-Disconnect all the injectors. You DON'T want to mix these up. However, the connectors are only given enough wire length to reach their respective injectors so mixing them up shouldn't happen easily. There are red clip locks on each connector that you need to slide toward the back of to connector. After you slide the lock back , you can press the tab and slide it off the injector. I broke almost every red clip lock trying to get them off because of how dried out and brittle they were. They are not required for the connector to stay on, they just prevent the tab from being pressed.
-There any many wires and hoses/tubes that run over the fuel rail to get to their destination. Push aside/tuck away all you can to clear the area for fuel rail removal. You DON'T want to man handle the fuel rail because you can cause damage to the injectors which will still be attached. One thing to keep in mind are the EVAP/Breather hoses coming
off the driver's side of the throttle body. They are hard plastic and after a while under the hood get VERY brittle. I broke one while just trying to get it off the throttle body.
-After clearing as much as possible around the Fuel Rail, turn your attention to the Fuel Rail connection. There is a silver safety lock that you must remove first. See Picture
-Now that the safety clip is removed you have to either use a tool designed to disconnect fuel rail fittings or a little trick I found. If you have the tool...GREAT! Slide the tool underneath the connector and you will be able to pull the connector off. If you don't have the special tool you can do what I did. Cut a strip of plastic out of a store bought milk
or water jug that's about 2" long and 1/2 inch thick. See Picture
-Take the strip, wrap it around the fuel inlet tube, and then push/slide it up into the connector. This will push the 4 clips inside the connector away from the tube and allow it to separate. You may have to wiggle it a bit to get it to disengage. See Picture
-Now that the Fuel Line is disconnected from the rail, it's time to remove the rail from the engine. Ensure that the areas around the injector holes are clean and free of any debris. You don't want dirt falling into the cylinders/intake valves. Remove the 4 8mm bolts holding the fuel rail to the engine. There are two bolts on either side. See Picture
With the bolts out, you can work around the rail slowly loosening and pulling the injectors out of their ports. BE GENTLE, the tip of the injectors are easily damaged. Pull the rail completely away from the engine. All 8 injectors will come with it. Now proceed to remove each injector from the fuel rail. There is a clip that holds them to the rail and in the right orientation. See Picture
Remove the clip by spreading it apart with your thumbs and pushing it toward the outside of the fuel rail. After the clip is off, the injector can be removed by pulling it away from the rail. The injectors for me took some good pulling/twisting to get them out.
This is a good time to replace any injectors that may be malfunctioning or damaged. Inspect for damage and replace if necessary.
---------Modify Fuel Rail -----------
Now it's time to modify the Fuel Rail. Proceed the following steps using either the one you got from the junk yard or the one you just removed (AT YOUR OWN RISK!). Keep in mind that if you are doing MOD1 you only need to do the below steps for the passenger side of the rail since it's the only side that will be used.
Take your Fuel Rail and using masking tape measure up the crossover 4" at either side, this is where you will cut the crossover and separate the two sides. See Pictures
Using your sandpaper, clean the cut ends of the existing crossover tube and remove any sharp edges. Be careful not to let any dirt/debris/sandpaper grit fall into either rail. Otherwise the injectors could pick it up and get clogged.
------------Build Main Fuel Feed-------------
Proceed to build the main feed out of these parts (More details on the parts in the first thread):
-6AN Hose to 6AN Female 90° Elbow
-6AN Hose to 6AN Female straight
-6AN Male to 5/16 Male Push-on EFI
-5.5" of 6AN Hose (Measure to ensure 5.5" is correct for your application)
Assemble the parts as seen below.
Using Push-Loc (Or Push-On, Twist-Loc) Hose with matching fittings can be pretty tricky. The barbs on the fittings are larger and sharper to grab the hose strong enough as to not need clamps. One trick that I've read about is coating the fitting and inside of hose with dish soap. Then using a vise to hold the fitting (NOT too tightly!! The fittings are aluminum and will crush easily in a vise!), grasp the hose and push it onto the bard end of the fitting until the hose pushes against the hose cap included on the fitting and doesn't turn freely. See Picture
Once the Main Feed is complete you can now move on to either constructing Mod 1 OR Mod 2 depending on what you want to do and what you can afford.
I will cover both in the next steps starting with MOD 1.
In this write-up I will guide you on how to modify the Fuel Rail on your 4.7L engine. I will discuss two different ways to do this, one which is more cost effective and the other which better achieves the goals of this modification.
What are the goals of this modification you ask? They are twofold:
1. To decrease the amount of time fuel spends in the fuel rail. This lowers the total
temperature of fuel and reduces differences of temperatures between each injector.
2. Balance the flow and pressure of fuel among all the injectors.
This modification is based off the idea of another fellow who did this to his Dakota. You can find his write-up here and I credit him for coming up with this mod:
http://www.dakota-durango.com/forum/showthread.php?t=116570&page=3
He did research on the temperature of fuel, how it affects the efficiency of the engine, and Duner's Fuel Rail cooling. He came to the conclusion that it's not entirely fuel temperature that affects the engine's efficiency therefore cooling the fuel may not be the answer. Instead the temperature of the fuel at each injector needs to be uniform to allow similar combustion efficiency in each cylinder. This should increase efficiency and take some work away from the computer as it doesn't have to try to achieve an optimal fuel/air ratio in cylinders that are all burning differently.
After completing this mod I have noticed that my throttle response is a lot quicker and my Jeep has more power as it keeps pulling hard through each gear. I am still evaluating any increase in MPG but so far it looks like 1-3 extra MPG.
I wonder if the last cylinder in bank 2 is so problem prone because it's the last cylinder in the fuel rail and therefore it burns the hottest.
The two ways to do this are:
1. With two fuel rails. The one on your engine now (or another) and another from a junk
yard or wherever. You need two passenger side rails (this side has a 4AN pressure
test port that will be used as the new fuel input).
2. Using your existing (or an extra) fuel rail only. Doesn't provide quite the cooling and
efficiency of distribution of fuel. I HIGHLY recommend buying an extra rail to do
this as you could leave your engine disabled if something goes wrong.
Tools Needed:
-8mm socket for the fuel rail bolts
-10mm socket for the spark plug coils and resonator box
-Shop towels for cleaning up spilt gas and cleaning components
-Flat Head Screwdriver OR socket for hose clamps
-Access to a Vise
-Hack saw (or Dremel) with a good blade for metal cutting
-Masking Tape for marking where to cut the fuel rail
-EFI Fuel Rail Disconnect Tool, or in my case, a strip of plastic cut off an empty milk jug
-Valve Stem Core Remover (only needed for Mod 1)
Parts needed for either mod:
-6AN Push-Loc Hose Barb to 6AN female 90° Elbow (JEGS #110071)
-6AN Push-Loc Hose Barb to 6AN female straight (JEGS #110051)
-6AN Male to 5/16 Male Push-on EFI (JEGS #640930)
-6 Fuel Injection Hose Clamps (JEGS #16047, 10-pack)
-200+ grit sand paper
Parts needed strictly for Modification 1: (Push-Loc = Push-On = Twist-Loc)
-Fuel Rail off a 4.7L engine in good shape. Can be taken off a Dodge or a Jeep, should
be identical but check to make sure. I got one from a salvage yard for $50
-1 foot of 6AN push-loc (or twist-loc) hose (make sure it's safe for gasoline) (6AN = 3/8)
-2 feet of 4AN push-loc (or twist-loc) hose (make sure it's safe for gasoline) (4AN = 1/4)
-2 3/8" x 1" barbed hose plugs for capping off the cut crossover ends
-6AN x 4AN x 4AN all male y fitting (Got off EBay for $15)
-Two 45° 4AN Push-On Hose Barb to 4AN Female fittings (SUMMIT #MRG-P454)
-Two 120° 4AN Push-On Hose Barb to 4AN Female Fittings (SUMMIT #MRG-P1204)
Parts needed strictly for Modification 2: (Push-Loc = Push-On = Twist-Loc)
-2 feet of 6AN push-loc hose (make sure it's safe for gasoline) (6AN = 3/8)
-6AN x 6AN x 6AN all male Y-fitting (Got off EBay for $18)
-EFI Fuel Rail Fitting - 6AN Male to 5/16" Hard Line (JEGS #103100)
-6AN Flare Cap (JEGS #110312)
-Two 45° 6AN Push-Loc Hose Barb to 6AN Female fittings (JEGS #110061)
Pictures of the parts are below (I got the Y-Fittings off of Ebay for about $15 each):
Parts from JEGS:
Parts from SUMMIT
Hose Plugs (Got off Ebay)
Fuel Rail:
Let's get to it!
---------Dissasembly----------
-Remove the Fuel Pump Relay switch found in the fuse box under the hood. See Picture
-Start your engine, it will die after a few seconds. Then keep cranking until the engine no longer sputters. This releases the pressure in the Fuel System.
-Disconnect the negative terminal of your battery and isolate
-Remove your intake resonator and hose. Remove more if necessary to gain easy access to the fuel rail.
-Remove the 8 ignition coils from the engine. All the coils are the same so the order in which you reinstall them really doesn't matter. The nuts are 10mm in size. Keep in mind the location of the resistors and the grounding straps mounted on 4 of the coils. See picture below, there is a resistor and strap on either side of the engine.
-Disconnect all the injectors. You DON'T want to mix these up. However, the connectors are only given enough wire length to reach their respective injectors so mixing them up shouldn't happen easily. There are red clip locks on each connector that you need to slide toward the back of to connector. After you slide the lock back , you can press the tab and slide it off the injector. I broke almost every red clip lock trying to get them off because of how dried out and brittle they were. They are not required for the connector to stay on, they just prevent the tab from being pressed.
-There any many wires and hoses/tubes that run over the fuel rail to get to their destination. Push aside/tuck away all you can to clear the area for fuel rail removal. You DON'T want to man handle the fuel rail because you can cause damage to the injectors which will still be attached. One thing to keep in mind are the EVAP/Breather hoses coming
off the driver's side of the throttle body. They are hard plastic and after a while under the hood get VERY brittle. I broke one while just trying to get it off the throttle body.
-After clearing as much as possible around the Fuel Rail, turn your attention to the Fuel Rail connection. There is a silver safety lock that you must remove first. See Picture
-Now that the safety clip is removed you have to either use a tool designed to disconnect fuel rail fittings or a little trick I found. If you have the tool...GREAT! Slide the tool underneath the connector and you will be able to pull the connector off. If you don't have the special tool you can do what I did. Cut a strip of plastic out of a store bought milk
or water jug that's about 2" long and 1/2 inch thick. See Picture
-Take the strip, wrap it around the fuel inlet tube, and then push/slide it up into the connector. This will push the 4 clips inside the connector away from the tube and allow it to separate. You may have to wiggle it a bit to get it to disengage. See Picture
-Now that the Fuel Line is disconnected from the rail, it's time to remove the rail from the engine. Ensure that the areas around the injector holes are clean and free of any debris. You don't want dirt falling into the cylinders/intake valves. Remove the 4 8mm bolts holding the fuel rail to the engine. There are two bolts on either side. See Picture
With the bolts out, you can work around the rail slowly loosening and pulling the injectors out of their ports. BE GENTLE, the tip of the injectors are easily damaged. Pull the rail completely away from the engine. All 8 injectors will come with it. Now proceed to remove each injector from the fuel rail. There is a clip that holds them to the rail and in the right orientation. See Picture
Remove the clip by spreading it apart with your thumbs and pushing it toward the outside of the fuel rail. After the clip is off, the injector can be removed by pulling it away from the rail. The injectors for me took some good pulling/twisting to get them out.
This is a good time to replace any injectors that may be malfunctioning or damaged. Inspect for damage and replace if necessary.
---------Modify Fuel Rail -----------
Now it's time to modify the Fuel Rail. Proceed the following steps using either the one you got from the junk yard or the one you just removed (AT YOUR OWN RISK!). Keep in mind that if you are doing MOD1 you only need to do the below steps for the passenger side of the rail since it's the only side that will be used.
Take your Fuel Rail and using masking tape measure up the crossover 4" at either side, this is where you will cut the crossover and separate the two sides. See Pictures
Using your sandpaper, clean the cut ends of the existing crossover tube and remove any sharp edges. Be careful not to let any dirt/debris/sandpaper grit fall into either rail. Otherwise the injectors could pick it up and get clogged.
------------Build Main Fuel Feed-------------
Proceed to build the main feed out of these parts (More details on the parts in the first thread):
-6AN Hose to 6AN Female 90° Elbow
-6AN Hose to 6AN Female straight
-6AN Male to 5/16 Male Push-on EFI
-5.5" of 6AN Hose (Measure to ensure 5.5" is correct for your application)
Assemble the parts as seen below.
Using Push-Loc (Or Push-On, Twist-Loc) Hose with matching fittings can be pretty tricky. The barbs on the fittings are larger and sharper to grab the hose strong enough as to not need clamps. One trick that I've read about is coating the fitting and inside of hose with dish soap. Then using a vise to hold the fitting (NOT too tightly!! The fittings are aluminum and will crush easily in a vise!), grasp the hose and push it onto the bard end of the fitting until the hose pushes against the hose cap included on the fitting and doesn't turn freely. See Picture
Once the Main Feed is complete you can now move on to either constructing Mod 1 OR Mod 2 depending on what you want to do and what you can afford.
I will cover both in the next steps starting with MOD 1.