PureFlow AirDog 98.5-04 Dodge 24V 5.9L Cummins (w/o Fuel Pump) FP-100-4G Fuel Air Separation System
The AirDog FP-100-4G, part A4SPBD101, is for 1998.5-2004 Dodge Ram 5.9L 24-valve Cummins trucks that still use the factory lift pump on the engine block. Owners usually come looking for it after a block pump quits, after a VP44 failure, or when a gauge shows supply pressure falling under load. This kit replaces the block pump with a frame-mounted lift pump that also filters and separates water and air.
On these trucks the factory electric lift pump sits on the side of the block and feeds the filter housing, which feeds the VP44 or CP3. The AirDog pulls fuel from the factory suction fitting at the tank. It sends that fuel through a water separator, a gerotor pump and a 2 micron filter, then delivers it straight to the injection pump. Both the block pump and the factory filter housing are bypassed. Excess fuel and air return to the tank through a tee in the filler neck. It flows 100 gallons per hour, enough for a stock or lightly modified truck.
Turn the key to run and listen for the block pump. Then put a gauge on the injection pump inlet and read it at idle and under load. If pressure falls away under load, the supply side needs attention. Before you order, confirm nobody has added an in-tank pump. If the tank has one, AirDog says this kit will not work. You need the FP-100-4G with in-tank pump, which includes a draw straw. For drivability complaints that could be the transmission instead, see 47RE harsh and delayed shifts.
AirDog lists A4SPBD101 for 1998.5, 1999, 2000, 2001, 2002, 2003 and 2004 Dodge/Ram 5.9L Cummins without an in-tank fuel pump. The instructions cover both the 1998.5-2002 VP44 trucks and the 2003-2004 CP3 trucks. It does not fit 2004.5 and later trucks or 12-valve engines. If you want the newer adjustable design, the AirDog II-5G DF-100 without pump fits the same trucks. Send us the year and VIN if you are unsure. You can find drivetrain parts for these trucks under 48RE and 47RE.
| Brand | AirDog |
| Part number | A4SPBD101 |
| Fits | PureFlow AirDog 98.5-04 Dodge 24V 5.9L Cummins (w/o Fuel Pump) FP-100-4G Fuel Air Separation System |
| Type | Fuel Air Separators |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Yes. The FP-100-4G supplies the VP44 or CP3 directly and bypasses the factory block pump and filter housing. The relay plugs into the connector the block pump used, so the ECM still switches it.
Do not use this version. AirDog says a truck with an in-tank pump needs kit A4SPBD153, or a draw straw or sump. Pulling through the in-tank pump will damage it.
On 1998.5-2002 VP44 trucks, yes. It is no longer used. On 2003-2004 CP3 trucks, you need a filter bypass because the engine return flows through that housing.
It is preset at 15 psi, plus or minus 2 psi, by a fixed ball and spring regulator. A different pressure needs a different spring from AirDog.
This is the Original AirDog design with a fixed regulator and the filter and separator mounted on the pump. The II-5G is the newer adjustable-pressure design. Both fit 1998.5-2004 5.9L 24-valve trucks without an in-tank pump.
