Fuel pump electrics
Discussion
Just had the classic engine stop, then no fuel pump noise when turning the ignition on. Back home thanks to a nice man with a big trailer and the flashing lights...
Diagnostics using a Digital Voltmeter gave 12v at the pump but the pump wpuld not run and a 5w bulb would not light. Wired pump direct to 12v and it ran ok drawing about 7 Amps. Confusing, but plodded through all the relays, connectors etc and eventually found the fault to be the contacts in the Inertia Switch with very high resistance. Removed the switch, tripped and reset it a few times with some Electrolube contact cleaner sprayed into it and all was well. (Good for fuses & connectors too).
1. The BITSbox is very useful for proving that the ECU is powered via the black base relay (red led) and ok (no fault codes) www.bespokeintelligentsystems.co.u
2. Bosch electronic relays (P/No. 0332 014 112) can be obtained from Camberley Auto factors for just £4.50 each BUT there will be a £7 carriage charge from Bosch (even to their own agents!) for small value orders if you want them next day. Still worth it though.
Ian.
Diagnostics using a Digital Voltmeter gave 12v at the pump but the pump wpuld not run and a 5w bulb would not light. Wired pump direct to 12v and it ran ok drawing about 7 Amps. Confusing, but plodded through all the relays, connectors etc and eventually found the fault to be the contacts in the Inertia Switch with very high resistance. Removed the switch, tripped and reset it a few times with some Electrolube contact cleaner sprayed into it and all was well. (Good for fuses & connectors too).
1. The BITSbox is very useful for proving that the ECU is powered via the black base relay (red led) and ok (no fault codes) www.bespokeintelligentsystems.co.u
2. Bosch electronic relays (P/No. 0332 014 112) can be obtained from Camberley Auto factors for just £4.50 each BUT there will be a £7 carriage charge from Bosch (even to their own agents!) for small value orders if you want them next day. Still worth it though.
Ian.
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