Dodge Cummins Diesel Forum - View Single Post - Anatomy of a Lift Pump

Gary - K7GLD · 01-02-2006, 12:58 PM

(continued)

Below, we see the disassembled motor section on the left, next to the pump section on the right - as previously mentioned, the only way to disassemble the motor is to cut it open, which totally destroys it for further use. In the housing seen above the motor armature, on the left side, is the spring-loaded ball check valve used to regulate fuel pressure.

This is a VERY common failure point, when either the spring fails, or the ball beats the seat out of the housing, allowing fuel to merely circulate between the pump and motor, with none or little actually getting to the VP-44 injection pump. And as can be seen fuel actually does flow thru the motor as well as the pump inself in normal operation.

Here's a closeup shot down the inside of the motor, showing the bottom bearing and the green circuit board with electronics to eliminate static radiation in normal operation - also note the excellent condition of the brushes and other components. This pump had 110,000 miles on it when removed from service, and that only as a maintenance procedure, since it was still operating perfectly!

SO, there you have the anatomy of a LP, how it works, and some of the more common failure points!

__________________
White '02 Quad cab, NV5600, GAUGES! Comp, Walbro, DTT SS intake, Rip's 4 in. exhaust, Don M's 1.6's, DSS, Frantz oil bypass & fuel filters, Amsoil air filter, MOBILE Ham Radio-IC-706, 600 watt amp, '88 Kit 24 ft. 5er, 418 HP/978 Tq., 24 ft KIT 5er.

01-02-2006, 12:58 PM	#2 (permalink)
Gary - K7GLD Tech Specialist Join Date: Nov 2005 Location: Canyon City Oregon Posts: 1,370 Gary - K7GLD's Truck Pics	(continued) Below, we see the disassembled motor section on the left, next to the pump section on the right - as previously mentioned, the only way to disassemble the motor is to cut it open, which totally destroys it for further use. In the housing seen above the motor armature, on the left side, is the spring-loaded ball check valve used to regulate fuel pressure. This is a VERY common failure point, when either the spring fails, or the ball beats the seat out of the housing, allowing fuel to merely circulate between the pump and motor, with none or little actually getting to the VP-44 injection pump. And as can be seen fuel actually does flow thru the motor as well as the pump inself in normal operation. Here's a closeup shot down the inside of the motor, showing the bottom bearing and the green circuit board with electronics to eliminate static radiation in normal operation - also note the excellent condition of the brushes and other components. This pump had 110,000 miles on it when removed from service, and that only as a maintenance procedure, since it was still operating perfectly! SO, there you have the anatomy of a LP, how it works, and some of the more common failure points! __________________ White '02 Quad cab, NV5600, GAUGES! Comp, Walbro, DTT SS intake, Rip's 4 in. exhaust, Don M's 1.6's, DSS, Frantz oil bypass & fuel filters, Amsoil air filter, MOBILE Ham Radio-IC-706, 600 watt amp, '88 Kit 24 ft. 5er, 418 HP/978 Tq., 24 ft KIT 5er.