The Garage - Injectors
Injectors & Aluminum Fuel Rails for a starving Magnum!

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Last Updated: 12/3/2013
Fuel Injectors & Rails

Summit Racing Equipment
Address: P.O. Box 909
Akron, OH 44398-6177
Phone: 800-230-3030
Fax: 330-630-5333
The Order Line is open 24 hours
a day, 7 days a week.
Click here to visit their website.
Address:1138 W. Ewing Street
Seattle, WA 98119
Phone: (800) 704-2157 - Toll Free
(206) 285-7836
Click here to visit their website.

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As soon as I hit the pedal I feel a bit of decreased throttle response and a big dead spot when I nail the gas at low RPMs especially in 1st or 2nd gear, simply said, I can feel that the engine wants to go but it doesn't!

I turned to Skype and forums for answers and after some lengthy chats with a few guys which really do know their stuff about engines (one of the guys is a repeat contender in the Engine Masters Challenge) concluded that this seems to be an injector problem. One or some injectors could be bad or I just simply need larger ones as the engine is not getting enough fuel.

With my engine producing close to 500 HP on the crank it could be a good idea to look into an upgrade from the OEM injectors.

The stock OEM 19 lbs. injectors are good to about 350-400HP (on the crank) and I am so beyond of that number, I now know that bigger sized injectors are no longer a waste of money but could bring the wanted improvement. I have made so many upgrades to my Magnum engine and totally neglected that it could be starving for fuel.

The 5.9l Magnum runs from the factory on 49.2 psi (+/- 2 psi) of fuel pressure and I have measured a pretty constant 50 psi on my Durango using a certified fuel pressure tester, keeping that in mind vs. the standard 43.5 psi fuel pressure they are measured under, it gives the OEM 19 lbs injector a approx. flow capacity of a 21 lbs injector due to the higher amount of pressure as mentioned before. Stepping up to the 24 lbs injectors should be perfect for my needs.

A 19 lb/hr injector size at 43.5 psi with a fuel pressure of 50 psi will have a flow capacity of 20.37 while a 24 lb/hr injector will have a flow capacity of 25.73.

Some people report that their Durango uses injectors made by Siemens (this company is owned by Chrysler to my knowledge) but the ones on my engine are made by Bosch and orange in color.

Bosch Injector colors:
Orange 19lbs
Light Blue 24lbs
Red 30lbs
Medium Blue 36lbs
A new set of Bosch or Accel injectors which are commonly used in the Magnums sell for around 300 bucks in most online stores such as Summit Racing Equipment.

Many engine experts suggesting to use Ford Racing injectors because they are sold as a matched (flow) set and can be found cheaper. The 24 lbs Ford Racing injectors are made by Bosch, too.

I was able to acquire a genuine set of 8 Ford Racing 24 lb fuel injectors (Bosch style Design III top feed injector, 260cc/min flow rate) from an ebay seller for about 90 bucks shipped which is a third of the price compared to a new set. The seller states that they have been tested, ultrasonically cleaned, rebuilt with new filters, O-rings and the proper Design III pintle caps, not yellow Design II caps that have been cut down with a razor blade.
The Design III Bosch Ford Racing injectors have a plastic body that doesn't absorb heat, keeping the fuel cooler than the previous generation with the metal body of the Design II injectors which heat up, in turn increasing the temperature of the fuel.
The Ford Racing Design III injectors also have the four-hole spray disk fuel delivery system (see picture to the right) in comparison to the single pintle of the Bosch & Denso Design II's for a much more efficient fuel-atomization. This all results in more horsepower and better fuel economy.

In any case, installing larger injectors causes the engine calibration needing to be changed to match the pulse width issued to the engines needs by the PCM. I can't go 50% up in injector size and expect the PCM to have any hope on controlling them.
That means I have to deal again with a new flash of the PCM as well.

What's involved to get this job done?
The 24 lbs Ford Racing injectors are a direct drop-in, no modifications to the fuel rail are needed as they are the Bosch (or Denso) Design III type injectors, but the wiring harness to connect the injectors calls for a set of new connectors to be soldered into the harness of the 2003 Magnum of my Durango.

That's pretty much what is needed, but I am not done just yet. I want for quite some time to exchange the OEM rails out for billet aluminum fuel rails. For a little under 100 bucks the Edelbrock Fuel Injection Kit (Part# Edelbrock 3641) which is a Fuel Rail Kit designed for the Mopar EFI Small Block 340/360 cid Engines and sold through Summit Racing Equipment seems to fit the bill with only minor modifications needed. For the fuel plumbing I decided to use the -AN (Army/Navy) fittings as found on high performance engines in funny cars, dragsters, etc. I purchased all of the fittings from Summit and 5 feet of -8 AN hose from ebay but I listed only 2" in the below shopping list because the rest is intended for a different project.

I also wanted to install a liquid dampened fuel pressure gauge under the hood close to the fuel rails. Well it all added up to quite a hefty price tag but see for yourself as you find my entire shopping list below:
Shopping List
Everything works as it should and I am very happy with the replacement as it is an OEM part and absolutely identical to what was installed when

Part Description
Price / Purchased at
24 LB Bosch Ford Racing Fuel Injectors Design III The 24 lbs All injectors have been tested, ultrasonically cleaned, re-tested and rebuilt with new filters, O-rings and the proper Design III pintle caps. (1 set of 8) $79.99 each
$79.99 + $10.00 s&h
@ smokestackj (ebay)
A set of pigtail connectors for the wiring harness to plug in the different type of injectors are needed for the 2003 Magnum. These can be found on ebay for a reasonable amount. ((8) NEW Fuel Injector Connectors Ford GM Chevy vette V8). (1) $16.00 each
$16.00 + $3.75 s&h
@ f0rrest (ebay)
Fuel Rails
Edelbrock Fuel Injection Kit (Part# Edelbrock 3641) Fuel Rail Kit; Mopar, EFI Small Block 340/360 cid Engine. (1 set of 2) $97.95 each
@ Summit Racing
Summit Racing SUM-220887B - Summit Racing® Hose EndsFitting, Hose End, 90 Degree, -8 AN Hose to Female -8 AN, Aluminum, Black Anodized, (2) $14.95 each
@ Summit Racing
Summit Racing SUM-220856B - Summit Racing® Fuel Pressure Gauge Fittings. Fitting, Pressure Gauge, Straight, Male -8 AN to Male 3/8 in. NPT, Aluminum, Black Anodized, (1) $8.99 each
@ Summit Racing
Trick Flow Specialties TFS-22388 - Trick Flow® TFX™ AN to NPT Adapter Fittings. Fitting, Adapter, Straight, Male -8 AN to Male 3/8 in. NPT, Aluminum, Black Anodized (1) $3.95 each
@ Summit Racing
-8 AN Braided Stainless Steel Fuel Line Hose 1500 PSI -0.43 Inside Dia., 0.64 Outside Dia.,1500 Max PSI, CPE synthetic rubber tube bonded with a woven Nylon Braid, 308 Stainless Steel outer braid. Op temps: -40 Degree F to +350 Degree F. Use w/ racing fuel, pump gas, fuels w/ethanol, alcohol based fuels, motor oil & coolant. (2') $5.19 each foot
$10.38 w/FREE s&h
@ Performance Dynamics Speed Shop (ebay)
Silicone Filled Fuel Pressure Gauge 0-100 PSI, Limited Edition CWB001001-1/2". Custom ordered gauge with limited supply. Stainless Steel Case / Brass Internals, 1/8" NPT center back connection, Silicone filled for vibration dampening, Accuracy: 2% of span at middle half of the scale. (1) $18.50 each
$18.50 + $8.00 s&h
@ y2llc (ebay)

The entire cost for this project at this point comes out to approximately $300.00 which also includes the s&h charges from Summit Racing. In addition I have ordered some brass stock for the planned machining of the fuel intake from, my favorite supplier for brass, aluminum, metal, and other material in small quantities. As usually, I order a bit more then needed at the moment just in case I make a mistake or want to have some extra material for use on a later project.

I already own Koul Tools 681 AN fitting assembly tools, a AN Braided Stainless Steel Hose Cutter, and assembly lubricant & anti-seize sealant from Russell (Russell Performance 671570). I keep a small sortiment of bolts & nuts on hand in my garage for just such a project and thus I didn't had to spend any additional money on this stuff.

However, not an inexpensive project by any means and I certainly didn't expect this to become this big of a wallet buster! Although I ordered the parts stretched out over a few month and thus it didn't hurt this much all at once, it's still a lot of money for a fuel rail setup. In hindsight, do I have regrets,...nah man, it's cool and I love this kind of stuff!

The basic procedure of this project is to take the currently running 19lbs injectors out and exchanging them for 24 lbs Ford Racing injectors, swap the OEM Fuel Rails for modified new aluminum rails and mount them by reusing but altering the existing brackets.
Machining a fuel intake from brass to connect the existing fuel supply line and install AN fittings to bridge both fuel rails. Furthermore I will install a fuel pressure gauge in the engine bay and add a second 1/8" NPT port for an electrical pressure sensor which leads later to an in-cab fuel pressure gauge.

Preparation & Setup:
I am getting started by thoroughly cleaning the entire engine bay (especially around the injector bosses) and blowing it afterwards out with compressed air in the hope to eliminate any dirt which could enter the interior of the engine.

Next is an important safety precaution for this type of project.
Relieving the high pressure fuel from the fuel system!

Here is a pic before I got started.

WARNING - DO NOT skip any steps!
If you think to skip the steps 1-4 to avoid DTC's, think again! If you don't relieve the high pressure first, excessive fuel will be forced into one cylinder chamber which can damage your engine and guaranteed will ruin your day! Again, DO NOT skip any steps!

Here is the standard procedure and it is the same procedure regardless if the fuel rail has a fuel pressure test valve or not!
(1) Remove fuel fill cap.
(2) Remove the fuel pump relay from thePower Distribution Center (PDC). The PDC is the main fusebox under the hood. For the correct relay refer to the diagram in the lid.
(3) Start and run the engine until it stalls. This should only take a few seconds.
(4) Attemt on restarting the engine until it will no longer run.
(5) Turn the ignition key to the OFF position.
(6) Unplug the connector from any fuel injector,
(7) Attach one end of a jumper wire with alligator clips (18 gauge or smaller) to either injector terminal.
(8) Connect the other end of the jumper wire to the positive side of the main battery.
(9) Connect one end of a second jumper wire to the remaining injector terminal,

CAUTION: Powering an injector for more than a few seconds will permanently damage the injector!

(10) Momentarily touch the other end of the jumper wire to the negative battery terminal for no more than two seconds.
(11) Place a rag or towel below the fuel line quick-connect fitting at the fuel rail.
(12) Disconnect the quick-connect fitting at the fuel rail.
(13) Return the fuel pump relay to the correct socket within the PDC (Main Fusebox).
(14) One or more Diagnostic Trouble Codes (DTC's) may have been stored in the PCM due to the removal of the fuel pump relay. Erase the DTC's with your Programmer or scan tool.

I go ahead and remove the air cleaner assembly (which includes to disconnect the IAT sensor because I did the IAT mod), any electrical connectors from the trottle body (TB) are next, and followed by unplugging all of the injector connectors.

Transmission Line Disconnect Tools
I then remove the quick-disconnect fuel line with the 5/16" (red) tool from my fuel line removal tool set (Performance Tool W89330).

This is a great tool set and for the 40 bucks it costs there is really no excuse not to have one handy in the garage.

I then put a rag under the disconnected fuel line and plugged the fuel supply end on the injector rail up with a plastic cap. I then proceeded to unbolt the brackets from the Hughes Intake manifold and removed the entire rail and injector assembly.

I emptied the fuel (and there was more than I thought) from the rails into a spare gas can I have in the shop.
I stuff pieces of clean shop towels in all of the injector bosses on the intake manifold to avoid any contamination.

The new Aluminum Fuel Rails
I could have prepped the aluminum fuel rails beforehand but I am in no rush. I start with preparing the new aluminum fuel rails to perfectly accept my NPT to -8AN fittings by re-chasing all threads. I am holding the rails in my vise with two pieces of 1x2" scrap wood which prevents marring of the new rails while I am working with them.

I use AlumTap which is great for cutting or chasing threads. I got this canister from Victor Machinery and usually I don't machine a lot and therfore it does last me quite a while. Alongside I am using compressed air. This works quite well to do this type of

I need to drill a hole into the aluminum fuel rail for the electrical pressure sensor to screw into. Again, some AlumTap on the drill bit will prevent it from seizing up in the hole, keeps it cool, and makes for a pretty clean cut.

Leveling the fuel rail in the drill vise is of upmost importance to achieve a perfect vertical hole.

With this step done, I am tapping the hole for the electrical pressure gauge sensor with a 1/8" NPT. This sensor is connected to a fuel pressure gauge installed within the cab.

With the use of Loctite thread sealant the electrical fuel pressure sensor is installed into the rail. Then I am wiring it up to a connector, one contact is for ground (negative), the other wire lead (sender) is connected to the in cab gauge .

Next on my to-do-list is modifying the brackets which came with the Hughes intake manifold and until now have been used to hold the OEM fuel rails in place.

I must say that the brackets didn't do a very good job at the original setup, it was almost impossible to properly align the OEM rails. In my new setup, although used for the same purpose, they will work perfectly!

To get this done , starting with the passenger (right) side, I simply lined up the fuel rail by pushing it onto the old injectors, aligning it properly, and marking the fuel rail where the brackets need to be positioned. Then marking the brackets where they need to be cut.

The brackets are cut off at the marked positions using my hack saw and working the cut and edges with a metal file.

Now I am drilling mounting holes into the rail where they need to be fastened to, I make sure to give room between the injector bores and the hole for fastening the bracket with a bolt. All brackets for the passenger side have been now cut and temporary installed.

The rail is placed again onto the injectors and I am marking the brackets with a drill bit (the same bit which I used to drill the mounting holes). I then drill the brackets and tab them for the mounting bolts I am using.

The mounting bolts are hex bolts I already had in my parts bin. I chamfered and countersink the holes for a nice look. I then reinstall the rail and use nuts and washers until they are perfect aligned with the mounting holes in the intake. A bit of hammering and bending of the brackets was all what was needed to get this done. I used LocTite blue to prevent the bolts from rattling loose.

I am now cleaning the rail as good as it can get using degreaser, brake cleaner, and fuel. I stuff small pieces of shop towels into the rails and use a long bit extension to push it back and forward in it.

I finish the job by using my shotgun cleaning kit, which worked awesome for this purpose. When this was accomplished, I was ready to install a 3/8" NPT plug on the one end of the rail......and a -8 AN to 3/8" NPT fitting on one end of the rail as the below picture to the left shows.

To assure a perfect fit I had to grind down the edges of the throttle body adapter from the intake manifold a bit.
I used a simple sanding bit and a Dremel to do this. I covered all injectors and other open holes to avoid any particles from the grind to enter the intake.

After that was done I used a few drops of black engine enamel which I sprayed into a cup and then brushed on to it to protect the exposed metal from the grind and to hide this modification.

I proceeded with the install of the new injectors and the fuel rail. I used engine oil to keep the injector O-rings well lubricated which helped a lot with constantly putting on and taking off the rails for test fitting.

Everything did work out as intended and I was very happy with the progress made. Day one was now over and I was looking forward to a fresh start on the next day. It was just plain fun to work in my new extended garage/shop!

The driver side fuel rail was next. I repeated everything I did on the opposite side including modding and tapping the brackets for an identical setup on this side. I also drilled and tapped a hole into the side of the rail to accept the fuel intake nozzle I will be machining from brass.

I installed the Summit Racing Fuel Pressure Gauge Fitting which has a 1/8" NPT tapped hole to accept the mechanical fuel pressure gauge and mounted the new aluminum fuel rail finally to the brackets for good. I then proceed to get prepared for the -8 AN fitting connecting both fuel rails together.

The large AN Braided Stainless Steel Hose Cutter is a must have to cut this type of line. I have seen this done with cut-off wheels, hack saws, and other tools, but take my word for it, nothing beats this cutter. It produces a very clean cut and only takes a second.

My Koul Tools 681 AN fitting assembly tool finishes the rest, and a bit of assembly lubricant & anti-seize sealant from Russell (Russell Performance 671570) makes this job a smooth one.

After I completed the line I installed it between the rails and tightened everything up very well to avoid any leaks.

Machining the Fuel Intake Nozzle
It is always difficult to duplicate something if there are no drawings or specs available for.
Point in case, the Fuel Intake Nozzle which accepts the Dodge Quick-Connect fuel line assembly.

The picture to the right shows the fuel intake nozzle as found on the OEM rail. This was the part to be duplicated and it also needed to have a 1/8 NPT threaded end to be mounted or bolted into the new fuel rail which I already have prepped for it. Meassuring and creating a rough drawing was followed by finding a solid piece of round brass stock for the piece to be machined from in my parts bin.

After a cup of coffee to get ready for the job, the brass was mounted into the chuck of my Harbor Freight Tools Desktop Lathe and the party started.

It did took a quite a bit of machining and several trials but finally the new fuel intake nozzle was finished and was looking good. Flattening the top and bottom of the nozzle rear threaded rim to accept a 13mm open end wrench which will not only make the install possible but would also be helpful if the nozzle needs to be removed or replaced at a later point in time.

After the new fuel supply nosle has been installed and the fuel line connected the sensors are plugged back in too.
Re-installing the air filter assembly finishes up the project.

Extensive leak testing was next, the mechanical fuel pressure gauge was indeed very helpful in that. I had one small leak on the passenger side raill but was solved by tightening the plug on the front end of the rail a bit more. That's also one of the reasons I declined offers to build a setup for someone else, you just have to have the vehicle there and do this on location. Everything checked out after that and the system held the pressure..

The engine started up without a single hiccup. At first I had a small issue with a rough idle, but the problem was solved after resetting the PCM. The gap in the RPM band is gone, in addition the engine seems to respond better to the pedal

Before and after!


AFTER - Driver side.

AFTER - Passenger Side.

I now have the 24lbs injectors in for a week and the only negative side of this project seems to be that I lost 2 mpg on average which may isn't a big deal for most but I already pay for high octane on the pump and I kinda miss to get the decent milage on my performance engine.

I decided to try the yellow 19 lbs Ford Racing injectors with the new multi (4 hole) spray pattern and can state that those work just as fine with the same pedal response as the blue top 24 lbs injectors but to my surprise I can happily report that my low mpg's are not only back but improved by about a half mpg. I am glad I gave it another shot! It never hurts to try something different and if I truly feel the need to swap in the 24 lbs injectors back in I have them waiting on the parts shelf ready for action.

This Project was completed on 04-30-2011

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