Lucas fuel pump

[Pezza]

Hi all, I'm not getting 12volts at the pump, I know I am losing it between the ignition and the fuel cut off. I intend to run via a relay/battery and an in line fuse a new wire to the pump. Anyone advise on ampage of wire I need ? 

 

Ta

 

[Waldi]

A Lucas pump draws little current, and 12V is not that bad. How much was the battery voltage when you did the measurement? If the engine was not running it will not be much over 12.5V when ignition is on and the pump is running.

In case you still want a by-pass (for the car-pump:) )

For the main wire 2.5mm2 should be ok. Do not forget to make a good earth with the same dia.

Regards,

Waldi

[Pezza]

Thanks the battery was 12.5v. The feed to the cut off from the ignition was 11.5v when I put a wire direct to the pump feed wire under the bonnet the car starts first time every time. And thank again for the info.

[Waldi]

Hi Pezza (what’s your name?),

I did not read your first post, correct, I now see you have not 12V but less then 12V at the pump. If the pump changes tone with the by-pass wire additionally connected (runs higher revs) I would clean or replace the inertia switch first, and check for corroded contacts etc.

I have a relays + inertia switch and heavier wiring, but with a Bosch pump which draws much more current.

Good luck,

Waldi

[Pezza]

Thanks it’s Perry but I’m called Pezza, the cut of is ok cause when I put the wire direct through the cut out I get battery voltage at the pump. Plus the resistance across the cut out is ok. 

I think I will end up with a pump kit and wiring kit from TRGB  

 

thanks for your your helpful advice have a great weekend. 

[iani]

14 minutes ago, Pezza said:

Thanks it’s Perry but I’m called Pezza, the cut of is ok cause when I put the wire direct through the cut out I get battery voltage at the pump. Plus the resistance across the cut out is ok. 

I think I will end up with a pump kit and wiring kit from TRGB  

 

thanks for your your helpful advice have a great weekend. 

I wouldn't recommend the TRGB wiring kit, it retains a lot of the original pump wiring, the kit you want is the Revington one, it completely replaces the original pump wiring, the TRGB pump kit is fine.

Edited May 17, 2019 by iani

[Pezza]

Thanks for that 

[astontr6]

16 hours ago, Pezza said:

Hi all, I'm not getting 12volts at the pump, I know I am losing it between the ignition and the fuel cut off. I intend to run via a relay/battery and an in line fuse a new wire to the pump. Anyone advise on ampage of wire I need ? 

 

Ta

 

Hi Pezza!

The key issue is to guard against volt drop when the ignition key is turned. The wire size was increased in size sometime in 1972 to 2mm sq. I changed mine to 3mmsq rated at 33 amps when I went over to a Bosch pump in the 1980's. Make sure the inertia switch contacts are clean as these can cause a problem. A good earth is a must.

Bruce.