Step 10 ? Replace the Fuel Injectors:
A new set of Fuel Injectors come with the Super Charger kit. They are larger then the stock injectors and therefore capable of flowing more fuel, in the same amount of time, then the stock units can.
The extra fuel is needed to maintain the correct Air Fuel ratios given the Blower will be pumping a lot more air into the engine.
What size injectors are they? (Why did I know you would ask that question? Cause everyone does! )
I believe but do not know that they are 28# Ford units. When Jack gets back from Moab I will call and find out.
WARNING Potential to Blow yourself Up! You are going to be opening up the fuel system of your Jeep. Take all necessary precautions so that you DO NOT blow yourself up by igniting the gas vapors in your shop!
- Open the doors for ventilation in your shop
If you smoke, stop during this step
Shut off all open flame heaters and any spark generated electrical devices
Etc.
Gas fumes explode folks, and if they explode on you, you won?t be able to read the rest of my boring write-up! (Read that; Don?t let this happen to you!)
Here are the tasks I did in the order I did them..
Make sure the battery is disconnected.
Find some high quality tape and an indelible ink (Sharpie) marking pen and label each of the fuel injector wiring harness plugs.
Start at the front of the engine with #1 and finish up in the back with #8.
(Just seeing if you are really reading this and paying attention, or if you need more sleep at night! There are only 6 injectors on the 4.0L engine and four injectors on the 2.5L)
Once you have all the injector harness plugs labeled, unplug all the injectors.
Relieve the fuel system pressure;
- Remove the gas tank filler cap
Remove the plastic cap from the Fuel Rail Pressure Test Port
Put a shop towel under the Test Port
Connect your Fuel Pressure Gauge to the Test Port
Put a ?catch? can under the gauge exhaust port
Press the relief button on the gauge and catch the gas
Here?s a picture.
You will probably get about 3 ounces of gas in the catch can. Please do something with it now. Don?t leave it in the shop to evaporate and increase the odds of a big bang!
- Remove the Pressure Gauge from the Test Port
Put the Plastic cap back on the Test Port
Put the Gas Tank Cap back on.
Disconnect the Fuel Line at the Fuel Rail:
Using compressed air blow away any dirt from around the Fuel Line to Fuel Rail fitting.
While you?re at it do the same around each of the Fuel Injectors where they enter the Intake Manifold.
Put a shop towel under the Fuel Line to Fuel Rail fitting.
This Fuel Fitting is called a ?Latch Clip Fitting?.
You will need a 5/16-inch (or 8mm) Fuel Line Disconnect Tool (NAPA $5) to release it.
DO NOT attempt to release this fitting with a screwdriver! (I promise you, you will be replacing fuel line if you do!)
This is a two-part fitting. The outer clip can be pried off with a screwdriver!
Save the clip, you will need it later to put this fitting back together.
Place the 5/16-inch (8mm) Fuel Line Disconnect Tool around the fuel line and push it into the fitting. This will release the plastic clips inside the fitting and allow you to separate the Fuel Line from the Fuel Rail.
Sorry I know this picture is very poor.
Please be prepared. Some gas will dribble out when the fitting is released.
Do something with the shop rag that just became soaked with gas, preferably outdoors.
Remove the Fuel Rail and Injector Assembly:
The injectors are held in place, sandwiched, between the Intake Manifold and the Fuel Rail.
The Fuel Rail is held in place with four (4) 10mm bolts, which you need to remove now.
Once these four bolts are out, remove the fuel rail, with injectors attached by ?gently? rocking it back and forth while pulling up on the assembly.
It will come out, but do not force things. Be gentle but firm!
You might want to be prepared with an outdoor work area prior to removing the fuel rail and injectors assemble from the engine to keep gas fumes in your shop as low as possible.
Here is what the Fuel Rail / Injector Assembly looks like sitting on a cardboard box outdoors because I wasn?t prepared with a work surface.
Remove the Fuel Injectors:
The Fuel Injectors are held to the Fuel Rail with small metal clips.
Remove the clip from each injector with a plier, then gently wiggle the injectors while you pull each one out.
Here is a picture showing two injectors de-coupled from the fuel rail and the clips.
Do not loose the metal clips. You will need them for the new injectors.
Where in the World are the ?O-Rings?:
Each injector has two ?O-rings?, one on the fuel rail end and one on the intake manifold end.
It is not uncommon for an ?O-ring? to remain in the Manifold or the Fuel Rail when you remove the injectors.
You have to find and account for all of them. If you don?t they will find you later when you go to put things back together.
Clean Intake Manifold and Fuel Rail Ports:
Take a good look inside the ports (holes) where the Fuel Injectors mount. If your Jeep has any significant mileage like mine, you will probably find a ?gummy varnish buildup? in there.
While I don?t know for sure, I believe this is caused by a dab of grease that is put on the Injector O-rings during assembly to help seat them in place. (You will be doing this too later to seat the new injectors.
I think this grease bakes in place over time forming the gummy stuff.
You need to clean this out to ensure the new injector ?o-rings? will seat and seal without any leaks.
Go raid your bathroom medicine chest for some ?Q-tips?. (If they are not in the medicine chest try the cabinet under the sink or the hall closet.)
Soak the end of a Q-tip with Carburetor Cleaner and work this gummy deposit out of each port in the fuel rail and the intake manifold.
(Don?t get ?cheap? on me now. When the q-tip starts to get dirty or the cotton end starts to come loose throw it away and grab a new one. Heck they give you about 4-gazillion ?Q-tips? per package for about 2 bucks at Wal-mart.
Install the New Injectors in the Fuel Rail:
There is a grove cut around one end of the injectors to fit the metal locking clips. This is the end that goes into the Fuel Rail.
Put a small dab of grease, or clean motor oil in the O-ring on the injector and slowly push a new injector into the fuel rail. DO NOT twist and turn the injector as you do, or you run the risk of nicking the O-ring and this WILL cause a leak.
Note: If you do nick an o-ring DO NOT use one off the old injectors, it will leak. Run over to NAPA and for 15 cents buy a new one. Heck for 15 cents and your proven ability to nick an o-ring already maybe you should be like me and buy 4 or 5 of them.
Just lubricate the O-ring and push it straight in.
Once seated, install the metal locking clip to the fuel rail and injector and move on to the next injector till they are all installed and secured to the fuel rail.
See that o-ring and the little black mark at 5 o?clock to the o-ring? That?s what a nicked o-ring looks like!
Make sure all the injector plugs are facing up so they can be plugged into the wiring harness once installed.
Install the Fuel Rail / Injector Assembly:
Place a small dab of grease around the o-ring on each injector and then press the injectors into the Intake Manifold as an assemble.
Do this carefully. Gently rock it back and forth while applying pressure downward. It will pop in place.
Make sure all injectors are seated all the way into the Intake Manifold..
Bolt the Fuel Rail down to the Intake Manifold using the four 10mm bolts and torque them down to
100 In/Lbsof torque.
Be Careful, that is INCH Pounds, NOT Foot Pounds of torque!
Reconnect the Fuel Line to the Fuel Rail by sliding the Fuel Line Fitting over the nipple on the Fuel Rail. It will give you a positive ?Click? when fully engaged.
Re-install the ?safety clip? on this fitting.
Plug the 6 injector wiring harness plugs onto the correct injectors. (Read your labels.)
The new injectors are installed and all that is left it to check for leaks.
Check for Leaks:
Reconnect your battery and pressurize the fuel system by turning the Ignition Key On and OFF several times. Each time you do this the fuel pump will run for bout 2 seconds. This will pressurize the fuel system.
Carefully check the Fuel Line to Fuel Rail fitting for leaks.
Also check the Fuel Rail to Injector Ports for leaks.
All should be fine, but if you find a leak now is the time to resolve the issue, not later.
The new, larger Fuel Injectors are now installed and ready to go. Check this task off your To-Do list.
Frank