UP95G - Heavy Duty Lift Pump for Cummins ISB / ISC / ISL CAPS Fuel System

UP95G - Heavy Duty Lift Pump for Cummins ISB / ISC / ISL CAPS Fuel System


Order Shipment Notice: 

Most orders are shipped within 24 hours from the order date. Orders placed on the weekend or after cutoff on Friday, and orders placed on select holidays are processed on the next business day. Please see our shipping terms for more information.

Made in America

Verified to have been manufactured in the USA

Part# UP95G - Heavy Duty Lift Pump for Cummins ISC & ISL CAPS Fuel System

***Our price includes technical assistance for installation***

Note: This pump will not have the correct fittings or fuel hose in it for an RV application since they are all different, you will need to source fittings and hose locally. Included is the wiring harness, pump and mounting bracket.


  • 1998.5-2003 Cummins 5.9L ISB (275/300HP) VP Fuel System
  • 1998.5-2005 Cummins 8.3L ISC (315/330/350HP) CAPS Fuel System
  • 1998.5-2003 Cummins 8.9L ISL (380/400HP) CAPS Fuel System

This heavy duty adjustable fuel pump is designed to meet the demands of the added strain of a performance module on the CAPS fuel system. The CAPS fuel system is known to be a weak fuel system as the factory lift pump only engages for the first 30-45 seconds after the key-switch is engaged. After this, the CAPS pump "pulls" the fuel and acts as the only pump in the system. By adding this heavy duty pump, not only are you taking away a lot of stress on the CAPS pump but you are also providing a steady flow of fuel that will help cool and lubricate the pump to increase the reliability and longevity of the CAPS pump. This adjustable pump is rated at 95 gallons of diesel fuel per hour and come preset at 15 PSI. Using a 1/8" Allen plug, you can make a quick clockwise adjustment to increase pressure or counter  clockwise to decrease pressure.

I have an ISL CM554 in a Newmar Mountain Aire
There is only one fuel filter in the system and it is between the lift pump and the low-pressure gear pump.
Do you disconnect the harness at the OEM lift pump and connect it to the new harness and connect the other end to the new pump?
Can the new pump’s inlet line be teed to the OEM lift pump’s tank supply line, and the new pump’s output line be teed to the OEM lift pump’s output line?
( Kenneth Brooks, 02/06/2023 )
This kit replaces the factory lift pump function, and runs constantly when the ignition is on. It has a separate stand alone harness to operate the new pump. The factory lift pump is left in place and the engine still uses the factory return lines. The fuel feed ports on the factory pump are no longer used and plugged. The new pump would then be plumbed in place of the old pump for the fuel feed. ( Support )
If this pump fails will this cause a restriction in flow or would motor home continue to run as normal? You mention factory lift pump could be left install. Would it be disconnected electrically, possibly could be hooked back up if new pump failed? ( Ricky, 12/08/2021 )
This pump does not have a bypass check valve integrated into it so it would create a restriction. You would be using the electrical connection from the old lift pump for the new, so I suppose you could plug the old back in but you'd still have to plumb it back into the system. If this is a worry for you, a simple bypass hose with check valve that goes around the pump could be installed. ( Support )
I purchased UP95G for my 2000 cummins 8.3 ISC , what is the optimum fuel pressure for the FASS pump to be set at? ( CHRIS RIDDLE, 04/20/2021 )
16-18 PSI is optimal. ( Support )
cummins ISC caps pump
you said it replaces the factory lift pump and factory pump only runs for 30 seconds. with that said how are you making it run all the time. if cutting into factory harness how hard is it to do. where at in the harness are you cutting at?
( KENLEY CARSON, 04/17/2020 )
The wiring harness we provide has the provisions built into it to demand the pump to run all the time and it does not require you to cut any wires.  ( Support )
does this replace the factory lift pump or a addition to factory lift pump? ( KENLEY CARSON, 03/26/2020 )
This replaces the stock lift pump. ( Support )
1999 Country Coach 8.3L ISC. Just checking for clarity, this pump is to be installed between the factory filters, with the factory Carter lift pump still in the circuit? No additional return hose needed etc...? Thanks! ( Johnny k , 12/28/2019 )
Yes, that is correct. We like to plumb them between the primary and secondary fuel filters and leave the OEM lift pump in place to utilize the fuel return line. ( Support )
How many amps does UP95G - Heavy Duty Lift Pump pull thanks ( Barry, 08/15/2019 )
This pump is pretty low amperage, between 3-7 amps is the specification. ( Support )
Do you place pump after primary filter even though fuel tank is 30 ft away thanks ( Bob, 08/14/2019 )
We prefer to install between the primary and secondary filters. The distance from the tank is no issue for this pump. ( Support )
2004 H R Endeavor 8.3 isc engine serial number is 46307911, Cummins saysThe OEN Pump transfer P/N 4935013 would not support a different pump for your Engine are they incorrect or talking about something different ( Barry Howard, 08/12/2019 )
The OEM pump is the only option that Cummins will say is compatible. The FASS pump that we offer is aftermarket so they would not recognize this part as correct even though it will work. ( Support )
Will this lift pump work with my 2004 8.3 isc engine serial number is 46307911 ( Barry, 08/12/2019 )
Yes, you have a CAPS fuel pump system so this would work. ( Support )
Motorhome VIN number 1RF32365221017223

E.S.N # 46147880
ISC CM554 8.3L 2001 Cummins

Hi I was looking at one of your lift pump it's rated at 15 psi I've been looking everywhere for my engines PSI range and I can't find it.

I even called coming and they told me it can't fall below five PSI but they couldn't find a maximum range.

If I buy this pump is the pre setting of 15 psi okay or do I turn it up or down?

If somehow you can find a way to find my range of my PSI for my fuel this way I can feel comfortable up turn it up and down as I choose.


( Adelino Mercado Jr, 09/13/2018 )
We find 15 PSI to work just fine. Any extra fuel will just be sent back through the return line to the tank. ( Support )
2002 Monaco ISC 350

Please correct me if the assumptions below are incorrect:

1. This is NOT intended to replace the existing electric "prime" pump but rather ensure that there is sufficient fuel supply by running at all times.
2. Other than installing this into the system and providing it with Key-on power no other modifications are required to the fuel system.
( Eric Lang, 04/06/2018 )
The UP95G lift pump does replace the existing electric "prime" pump but you don't have to remove the existing pump. There are modifications that we make to the electrical harness but other than installing the pump into the fuel system, no other modifications are required.  ( Support )
Is this a "kit" or is it just the pump? My motorhome is a 04 Country Coach with a ISL 400 engine with a Caps system. ( Norman , 07/26/2016 )


This is the pump and harness plus some miscellaneous fittings. For most applications you will need to purchase bulk fuel line and fittings from a local hydraulic shop.

( Support )
2000 Monaco Dynasty Cummins ISC 350 manufactured June 1999. Fuel and Water separator filters mounted on frame crossbeam in rear of engine compartment.

How does this pump integrate into the fuel system. Should it go between, before or after the filters.
( Ed Miller, 07/14/2016 )


We prefer to install the pump so that it is in between the two filters. Every coach is different so installations can vary widely but that is the preferred way to do it.

( Support )

Ask a question

Note: HTML is not translated!

Write a review

Please login or register to review

 The state of California requires that this warning be posted for people purchasing products that reside in California.

WARNING: Products may contain one or more chemicals known in the State of California to cause cancer and/or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov

Shipping Insurance Notice

NOTICE: For orders outside of United States

If you are placing an order to ship outside the United States, Shipping Insurance will be required and added automatically at checkout.


  • Views: 42001
  • Brand: FASS
  • Product Code: UP95G
  • Availability: In Stock
  • $808.65
  • $629.00

Available Options