Fass II Pump Install

This article is a guide to assist in the install of a Fass II pump for either the 98.5-02 (VP-44) models or the 03 and up (CP-3) vintages.The instructions that come with the pump have good detail and should be used as the main source of information or contact the vendor that supplied you with the product for technical assistance.

Here is the Fass II pump kit as received from your favorite BOMB support center, the kit is very complete with most everything you will need for the task at hand, the only thing additional you will need is about 15 or 20 zip ties for securing the new fuel line and the wiring harness. This Fass II kit is of good quality and is put together with quality materials and longevity in mind.



The first step in this process is to disconnect the existing fuel line connected to the fuel tank pickup tube; this can be a challenge if you have never done it before as most of the work is done by feel since you cannot see the actual tank module, I have found 2 different ways to get to the feed line pickup, first is to lay under the truck and reach up and on top of the tank you will feel it or if your truck isn’t equipped with wheel well liners then you can go in from inside the wheel well, if you choose this method it will be easier to remove the left rear wheel and support the truck with a rated jack stand for safety. The line you are after is the one toward the rear of the truck as you can see in this picture, notice how the blue retention clip is inside the plastic fuel line connector. The trick here is to squeeze the two tabs together as to release the clip from the shoulders of the pickup tube inlet, squeeze and pull the connector off, the blue retention clip will stay with the pickup tube inlet , then you simply pull the retention clip one side at a time towards you till it actually inverts itself, do this to both halves of the clip and it will slide right off. Don’t worry about ruining it as it won’t be needed for the Fass install.





OK step two is a good one and you will appreciate it later on. Get a 2 foot piece of old garden hose and slip it over the drain tube from your fuel filter housing and place a catch bucket under the hose, now open the filter drain valve, use you air compressor and a blow nozzle at the line you removed from the pickup tube and with only a few psi blow into the fuel line to force all fuel from the old line as well as the filter housing, this step will help you from being soaked in fuel while under the truck.

Step three is to remove the fuel line and OEM lift pump going into the fuel filter,

For a 03 and up truck you must actually remove the OEM pump from the back side of the fuel filter housing. , the old pump is held in position by 4 Allen bolts, save the bolts as you will need 2 of them later.

You are now ready to install the pump on the front bed support cross beam, temporarily mate the pump to the mounting bracket so you can fit it in place and mark the holes for drilling.

Once you have the holes drilled out to ¼” go ahead and mount the bracket only to the bed support beam.

Now with pump in hand you need to install the fittings to it, I used a couple rounds of Teflon tape on the fittings before screwing them in, stay a thread back so you don’t end up with some Teflon tape inside the fuel system using a 7/8” wrench tighten the two pushlock fittings into the inlet and outlet of the pump.

Before mounting the Fass II pump to its bracket take a good look at the markings on the pump, you will find a letter “T” for the fitting that needs to point toward the tank and a letter “E” to the fitting pointing towards the engine, using the 4 bolts provided in the kit secure the Fass pump to the mounting bracket.

Very Important--- Remember the position of the "T" port there is a small hole in the base directly next to the electric motor, this hole must aim directly toward the ground! Impropper installation of the pump can cause premature wear and void manufactures warrenty

Now with the pump installed we need to get the fuel lines going, notice I taped off the running end of the new fuel line, this is to keep any dirt out of the system, I mounted the new connector to the other end of the line, take this end and click it onto the pickup tube nozzle where you removed the OEM line from. Now stretch out the line and head towards the inlet side of the Fass pump, cut the line accordingly and be sure to mount the fuel pre filter between the tank and the pump, install it in a convenient place for future maintenance of the filter.




Now connect the supplied fuel line to the discharge side of the Fass pump and route the line towards the Mighty Cummins.


If your truck is a 98.5 -02 then mount the fuel line up to the fuel filter housing inlet with the new connector provided.

For a 03 and up truck install the filter block adapter with fuel line fitting on the back side of the fuel filter housing using two of the original Allen bolts from the OEM pump. Before mounting up the filter block adapter use your finger to ensure that the OEM O-ring is still in place inside the filter housing inlet hole. Use a small dab of oil on the o-ring to help prevent it from rolling. Using 2 of the original mounting bolts apply some thread lock provided with the kit and tighten the adaptor in place. Now secure the fuel line to the filter housing and we are looking good

OK the pump and fuel lines are complete so let’s move on and get the wiring harness installed

Find the end of the harness that connects to the Fass pump and route it down thru the engine compartment and head it toward the pump, slide the connector together at the pump and use some tie wraps to secure the wiring harness as well as the fuel line from the pump clear up to the fuel filter housing.

Now up in the engine compartment find the other end of the harness that clips into the original wiring connection from the ECM to the OEM lift pump, route it properly and clip it together and secure it with tie wraps.

The relay provided with the new harness can be mounted just about anywhere just keep it away from hot spots, I mounted mine on the firewall along with the inline fuse

Route the power and ground feed wires around the firewall and connect them up to the positive and negative battery terminal connections. You may have some extra wiring here so trim it accordingly to your application, the wire loom is nice.

OK at this point just go over everything you messed with to insure it is complete and you will be ready for a test fire.

Now remember you still have the catch bucket and hose extension attached to the filter housing drain? Good......... since the drain valve is in the open position give the truck a bump start but don’t start the motor, jump out of the truck and run around to the engine bay and as soon as fuel comes gushing out the drain tube close the drain valve, Now turn the key off and then do the key bump one more time to purge the system of any air in the system, if there is still air in the lines the new Fass will easily pump it thru and back via the return line to the tank.

A pic of the pump installed



Start the truck and check for leaks……….have fun dudes the job is complete, no more worries of fueling issues !!! You will now find that you won’t watch your fuel pressure gauge like you used to, but when you do look at your gauge it will look something like this hehehehehe, feels good huh





Cheers, Kevin