This blog, in addition to the usual maintenance details for classic mini cars, an attempt is made to explain the "whys" and "wherefores" of the various jobs.

Thursday, 15 October 2009

Diagnosing Pump Troubles

Symptoms of air leakage on the suction side of the pump are rapid operation of the pump and reduced fuel delivery. Apart from checking the cover plate gasket, make sure that there is no leakage at the rubber connexion on the suction line. Leaks will be revealed by the seepage of fuel when the pump is not operating.

If the pump does not operate when the ignition is switched on, first check that the connexion between the supply lead and the pump body is clean and secure. This lead is connected to the upper terminal. Also check the earth lead, connected to the lower terminal. If all appears to be in order, disconnect the supply lead and check, with a test lamp or voltmeter, whether current is reaching the end of the lead when the ignition is switched on. If no current is evident the fault must lie some¬where in the wiring between the pump and the ignition switch. The pump is not fed from the fuse that protects the other accessories which are controlled by the ignition switch.

Assuming that current is reaching the pump, remove the upper cover and clean the contact-breaker points by drawing a piece of clean paper or card between them, taking great care not to stress the contact blades.

If none of the attentions just described succeeds in restoring normal pumping action, there is, unfortunately, no alternative but to fit a replacement pump.