Pump Electrical Controls; Resistive Check; Pump Absorption Control - PIAGGIO 500 cc Service Manual

Pump electrical controls

Resistive check

Disconnect the pump support connector. Using a tester
measure the resistance of the pump windings.
Connect the tester prods to the pump support pins as
shown in the figure.
Resistance = ~1.5 Ω
On meeting with infinite resistance replace the pump.
With infinite resistance, the pump will not turn.
With resistance close to 0 W the pump absorbs exces-
sively with the possibility that the 10 A fuse n° 2 will burn
out. Proceed with controls as below.

Pump absorption control

Pump absorption may vary depending on:
- feed tension
- running-in of the pump
- adjusting pressure
- cleanliness of the delivery filter
To carry out a control of the current absorbed, proceed
as follows:
- disconnect the pump command electromagnetic
switch connector
- with the ignition key set to "OFF", jump 30-87 to the
connector using the tester prods in amperometer
function (see figure).
- check the pump revolution and its absorption
Current absorbed = ~ 3.5 - 4.2 A
NOTE: this absorption refers when:
- feed tension = ~ 12 V
- pump run-in
- system pressure = 300 KPa (3 BAR)
- clean fuel filter
A dirty filter causes absorption increase.
If the overpressure valve is opened the pump absorbs
~ 6-7 A
If excessive absorptions are revealed (> 5A) proceed
with replacement of the filter. See page 9-54 overhaul
of the support pump.
If the anomaly persists replace the pump.
Fuel injection
9
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