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MG MGB GT V8 Factory Originals Technical - EFI Pump Wiring

Does anyone know what current a Bosch EFI pump draws ? The crux of the matter is, will the existing wiring be able to handle the original pump plus the EFI one ? Or will I have to run a separate line for the EFI pump ? Thanks for any replies. Barrie E
Barrie Egerton

The EFI pump needs to be fed through the 40 amp relay that is part of the fuel injection wiring harness. The computer needs to keep control of the pump in order to control the whole system, so you can't just hook it up hot all the time, and hope for the best.


Not sure which EFI you are using. But if I rememeber you are using Rover EFI. Sounds like the SDI uses the pump to regulate pressure?? The Ford system does not do that, it has a mechanical regulator ont he fuel rail that controls it to a set pressure. That is up untill 1999 when on the Ford explorers they went to a retunless system and then modulated the pump to maintain pressure.
Larry Embrey

There is a vacuum controlled regulator on the fuel rail, but the system still stops and starts the fuel pump at various stages in the starting and stopping process. I.e. When you first turn the ignition to the on position, the injection turns on the fuel pump for 3-5 seconds to prime the system, then shuts it off till you hold the ignition on the start position. When the ecu recognizes that you've stopped cranking (no more pulse from the coil wire) it stops the fuel pump, and waits for you to attempt cranking again.


In future, I promise to do a bit more research before I ask a dumb question. Thanks, Barrie E
Barrie Egerton

Barrie - you may also want to think about accident protection - the RV8 and SD1 have a separate impact cut out in the pump circuit -

The impact switch is well worth incorporating, I've mounted mine on the side of the pedal box under the bonnet, It means I can pull the pin and switch off
the fuel supply when working on the car,(ie when the high pressure fuel system springs a leak, which it has occasinally).and I suppose it could be used as an additional security device.

Michael barnfather

This thread was discussed between 04/10/2003 and 06/10/2003

MG MGB GT V8 Factory Originals Technical index

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