Fuel Pump - GRAUPNER JetCat P60 Instructions D'utilisation

[Seite 12]

Fuel pump

Once the turbine has ignited on propane gas, engine speed continues to increase due to the action of the
starter motor. At 4800 rpm the ECU switches on the fuel pump at minimum power. Starting from this initial
voltage, the pump is fed a slowly increasing voltage, causing the turbine to increase speed steadily. The
voltage which is supplied to the pump immediately after ignition is pre-set at the factory before shipping.
However, if you replace the fuel pump or the ECU it may be necessary to adjust the initial pump voltage.
The ECU includes a special function for adjusting the initial pump voltage; it can be called up as follows
(software version 2.01d and later).
1. Cut off the fuel supply to the turbine (one method is to run the fuel feed line back into the tank overflow).
If you don't cut off the fuel supply, the adjustment process will flood the turbine with fuel, and this
inevitably leads to a "hot start" next time you attempt to start the engine!!!
2. Switch off the electronics and connect the GSU (RC transmitter not required).
3. Press and hold the "Change Value/Item" button on the GSU.
4. Switch on the electronics.
5. Wait until the GSU screen shows the following message, then release the button.
Pump start volt.
Uaccelr1:
The pump can now be started and tested by pressing and holding the "RUN" button.
Press the "INFO" button to increase the initial voltage by one increment.
Press the "Min/Max" button to decrease the initial voltage by one increment.
The initial voltage should be set in such a way that the pump runs reliably at every setting, and the fuel is
metered "drop by drop" (you may need to press the RUN button repeatedly).
The proven range of values for the initial voltage is 0.1 to 0.25 V (default value: 0.2 Volt).
Press the "Manual" button to store the newly established setting once you have completed the adjustment
process; you are then returned to normal operation.
The following general rule applies:
Initial voltage too low:
If the initial voltage is set too low, a voltage will be supplied to the pump, but it may be too low to start
the pump running (-> red "pump running" LED lights up, but pump does not rotate). The likely result of
this situation is that the turbine will ignite, but may run for a very long time on the propane gas. It will
not pick up speed, as no fuel is being pumped into it. If the propane run period is excessive (> 10s) the
electronics will terminate the start process with the following error message "AccTimOut" (=
acceleration time-out - excessive time for speed rise process), or "Acc. Slow" (= acceleration too
slow).
Initial voltage too high:
If the initial voltage is set too high, too much fuel is injected into the engine at start-up, and this may
cause dangerous flames at the turbine efflux during the initial start-up phase. This is caused by
inadequate turbine speed relative to the amount of fuel being injected.
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