Easy to identify, there is no mechanical connection to the pump from the accelerator pedal, and very small cast flange to which the high pressure delivery lines attach. It is a compact and very capable pump when working correctly, often being used in very large applications such as buses and lorries, as well as Ford Focus to name but one!.
The VP44 is a fully electronic controlled pump. Early units had two ECU 's one internal to the pump and an external engine or vehicle mounted unit. Later pumps combine both ECU's in the pump case.
Being still relatively new, and untill recently, no service information or spare parts has been available, little is known as to its capability for use on Vegetable oils. Issues of pump problems associated with Biodiesel have been reported, where the methanol content attacks internal position sensors.
What is known, of failures on Diesel fuel, suggest a lubrication issue of the distributor rotor similar to the Lucas/CAV series. In common with the Lucas pumps, Fuel and hence lubrication is cut off to the rotorhead during conditions of overrun (engine braking)
Research also suggests any restriction in fuel supply to the pump, for instance a partial filter blockage could also cause damage to the pump, through lubrication starvation.
Early models were quite prone to failing on Diesel, and the distributor rotor assy, has been through three different updates since the pump was first made. Later pumps are therefore more reliable in this respect, but care must be excersised if attempting the use of Vegetable oils with these pumps.
-Ive just received a VP44, that Ive recently won on Ebay for the huge sum of 99p! It is intended for a Volvo FL250 Tractor Unit, and was manufactured late February 03, but I have other plans for it, such as a full strip-down and assessment for Vegetable oil use!
A preliminary inspection has been carried out, and found that the distributor rotor is of a similar size to the Lucas/CAV series, and as such, will probably cause trouble with cold oils
There appears to be a similarity in construction to both the Lucas/CAV, DPC and the Stanadyne DB 2 series
The Position Sensor appears to be a Hall-Effect device, similar to that used in Video Recorders, where they are used as reel-table rotation sensors. It is connected to the main FPCU ( fuel pump control unit, mounted at the top of the pump) by a rather delicate ribbon cable, of the type commonly used in Domestic Electronic equipment At present it is not understood what effect Methanol has on this sensor. If anyone has a VP44 position sensor thats failed on BioDiesel, --Please contact me so as I can compare it with a known good sensor to find its failure mode.
Sensor update, The Position sensor appears to be a set up of three coils, and not a Hall effect device as previously thought. The Average DC resistance of these is around 77-85 ohms.
A suspect dead VP44 pump can be tested before removal from the engine by first disconnecting the main plug, and locating pins 6 and 7. These are at the right hand side of the socket on the pump when looking at the socket with the pump top uppermost. The pins are numbered in the socket.
Connect a lead from a good earth or Batt - to pin 6
Connect a lead from Batt + to pin 7, Make sure the lead has a good contact, and capable of passing up to 30A, also, make sure it wont come loose when the engine starts, Dont allow it to come into contact with any other pin, or earth while connected to the battery!
tie back the plug that normally goes to the pump, to prevent shorts.
Operate engine starter, If engine starts and idles correctly, then there is a good chance the pump is fine.
Most problems are associated with bad connections, as some pass high currents which are prone to trouble. The contacts in the pump plug can work loose, but can be tightened carefully with a very small screw-driver.