how to wire in a second pump

[Howard Coleman]

i have completed my install of the Radium fuel tank sump which requires wiring in a second lift pump. 

i decided to tie into the B Plug Ign 7 wire for my lift pump as it was providing the signal to my primary fuel pump relay.

i would have preferred to tie into another pin, as you suggested, but decided i wouldn't have been able to set up the proper commands such as the Pre Crank Prime etc.  

the motor starts and seems to run fine... just for a brief log. 

i observe 2 problems:

when i turn on my master electrical switch, with the key off, i hear one or more of my relays vibrating.. cycling on and off at a fairly high rate. 

when i then turn on the key the fuel pumps Pre Crank Prime does not stop.

the only thing that has changed re the primary assemblage of relays is the tie in to another relay controlling the lift pump.

if there is some sort of problem using the tie in to the signal wire i would assume i would have to use, as you suggested, a GP Output.

i would greatly appreciate learning how to specifically set up that particular window. should i need to add the GP Output i will need a pin. what pin fits the plug? 

map in drive:

https://drive.google.com/file/d/1C0CTkNrQyMQ7n4j-7Izpb3D9oEjqLcv-/view?usp=share_link

log in drive:

https://drive.google.com/file/d/1zSpJJG6CriZYG5g5ly1fUEcRFPGpm7HU/view?usp=share_link

 

thank you

     

[Adamw]

If the relay is clicking when the ignition is off then that means you have constant 12V on one of the relay coils, it needs to be an ignition switched source if connected to an aux.  I dont think the ignition outputs can back feed so Im suspicious it may not be your new pump relay that is the problem.  Unplug all the relays and find out which on has 12V on pin 86 with ign sw off.  Im not sure why it would not turn off after priming but fix the live feed first then we can diagnose that if still present.

[Howard Coleman]

i should have entitled my post, "How not to wire a fuel pump."

thanks Adam for posting the most fundamental diagram. it has been ten years since i wired my V88 and i had forgotten that the ECU presents GROUND to the signal wire not V. after playing w numerous relays etc in desperation i revisited your post and actually looked carefully at it. 

all is super well w my Radium surge tank install now. tieing in to the original fuel pump signal wire for the lift pump appears to work well.