Mk1 Mk1a Petrol pumps reserve

[aust62]

FUEL RESERVE UNIT SWITCH

Just joined this site and dont know where to post a question so I will start here.

I have Rover P5 Mk 1A which I rescued in 2007 which has only 1 fuel pump connected to what appears to be the single out of tank line.

The hoses have been re-routed so.

This is for cars where there are 2 separate electric fuel pumps - main and reserve.

The Workshop Manual (Section Q  p18) refers to a "fuel reserve unit" in the fuel tank area which changes the fuel flow from main to reserve pump and presumably also activates the reserve fuel pump as same time when the dash reserve fuel switch is thrown. BUT there is no sketch of what this unit looks like (aka = in-line hose switch).

I presume its a 2 way solenoid switch ?

The circuit diagram in another section doesnt shed much light on it either.

Can anyone shed any light on this or show a photo of their unit and know where I can get one or something that does the same ?

And what is the circuit configuration of this switch relative to the reserve pump ?

I need to add one back and know the circuit.

A photo of a MK1A fuel tank, hoses and pump arrangement would be helpful.

My dad's Mk1 has the double type single pump so the configuration is different - there is no in-line switch as it is contained internally in the pump.

Thanks

[Phil Nottingham]

May 6, 2022 14:46:18 GMT aust62 said:

FUEL RESERVE UNIT SWITCH

Just joined this site and dont know where to post a question so I will start here.

I have Rover P5 Mk 1A which I rescued in 2007 which has only 1 fuel pump connected to what appears to be the single out of tank line.

The hoses have been re-routed so.

This is for cars where there are 2 separate electric fuel pumps - main and reserve.

The Workshop Manual (Section Q  p18) refers to a "fuel reserve unit" in the fuel tank area which changes the fuel flow from main to reserve pump and presumably also activates the reserve fuel pump as same time when the dash reserve fuel switch is thrown. BUT there is no sketch of what this unit looks like (aka = in-line hose switch).

I presume its a 2 way solenoid switch ?

The circuit diagram in another section doesnt shed much light on it either.

Can anyone shed any light on this or show a photo of their unit and know where I can get one or something that does the same ?

And what is the circuit configuration of this switch relative to the reserve pump ?

I need to add one back and know the circuit.

A photo of a MK1A fuel tank, hoses and pump arrangement would be helpful.

My dad's Mk1 has the double type single pump so the configuration is different - there is no in-line switch as it is contained internally in the pump.

Thanks

I will check the parts list tomorrow but I think the Mk1 and Mk1a had the old P2-P4 solenoid drop twin pipe that closed off the shorter main drop tube when the reserve switch was operated. This was designed for single pump set up but supply issues meant that P4s used with the twin and double pumps fitted to P4 95/110s from 1962-1964. There is no separate tank or reserve unit as such. Later P5s and P5Bs used a concentric drop tube with no solenoid 

[Phil Nottingham]

I have checked up on this with the parts list and it is the interim P4 twin pumps that should be fitted to Mk1a P5s - Mk1 should have 1 pump. Both Mk1 and Mk1a have a solenoid operated Reserve valve with twin drop pipes and a single outlet which branches on Mk1a to feed the extra reserve pump. The reserve solenoid is operated by a simple on/off switch on the dash for the Mk1 and a C/o switch on the Mk1a. This switch also switches off the main pump and activates the reserve one. The wiring diagram as with many Rover mods does not reflect the interim twin pump solenoid set up.  Mk2 Mk3 had the same C/o switch to swap over the Dual ended pumps but had a single outlet pickup with concentric drop pipes in the tank but no solenoid as it served no purpose and and pipework was simpler with the Dual ended pump.   The solenoid can be seen at the end of the pickup connection on the tank. They do stick and burn out and the drop/dip pipes can leak air. They can be reconditioned with care sometimes as new one are scarce and the drop pipes differ from P2 P3 and P4 models.  

What is your problem you wish resolving? 


I have no photo  of one of these solenoids for a P5 setup but this diagram may help