240 fuel pump problems

Alrighty, I'm doing a turbo conversion on my 240 and have popped a walbro 255 in the tank and bypassed the inline pump. I can get power to the pump by doing the old 4-6 fuse jump trick but otherwise nothing, and jumping the fuses makes it run constantly with or without key.
Ive just got the wires for the inline pump dangling under the car not connected to anything, i'm wondering if theres any shenanigans going on with the relays not letting the tank pump go without the inline pump or something.
Any advice fellas?

edit for more info: the car is a '79 244, swapped from a b21a to a b230fk+t and using the dash, wiring and diff from an '89 240 running lh2.4.
I went around with a test light yesterday. At the pump i've got power to the grey wire, nothing to black.

At the main relay i'm getting power to 30 and 86/1, turned to II im getting 30, 86/2, 87/1 and 85. Pump runs if I jump 30 to 87/2.
main relay looks something like this:

85 87/2 86/1
— — —
— — —
30 86/2 87/1

Im struggling to find it in any wiring diagrams but theres another little bosch relay near the main relay, I've got power to 30 but nothing else in any key position. There is also a mystery wire plugged into 85 that isnt going anywhere


I need an adult :(


  • What year 240?
    I think you need to add i was in an s80 with three wheels getting pulled backwards and was told to "hold on shit is about to get real".
  • well the body is '79, wiring is from an '89 running LH2.4
  • Cool,

    I'll post up a wiring diagram this evening,
    I believe you do need to do some things with the primary pump wiring off the top of my head
  • @Philia_Bear any luck with the wiring diagrams mate?
  • carnut222carnut222 (@carnut222) Daylesford VIC
    edited December 2018
    On your “mystery relay” if there’s a wire on terminal 85 going nowhere, the relay will not do anything. You would need power to one side of the relay coil (either 85 or 86) and ground to the other side to energise the relay. Sorry if I’m stating the obvious.
  • ahh ok, when it comes to electricity nothing is obvious for me, i've got no clue what i'm doing.
  • ahh ok, when it comes to electricity nothing is obvious for me, i've got no clue what i'm doing.
    No problem. Happy to help. Can you see where the other wires from the mystery relay go, particularly 87 as that would be feeding power to something once the relay is activated. As far as activating the relay, As I mentioned you’d need power and ground to 85 and 86 to activate it. You said 85 is going nowhere. Could that be the ground? If not, can you probe 86 and see if it is a ground or follow it and see if it goes to ground? It could be a Furphy and have nothing to do with your situation I suppose - these cars are pretty old so it may have been some old accessory or something that is no longer installed?
  • Also you said at pump you have power to grey wire, nothing to black. The pump should only have 2 wires - one will be power and one will be ground. So maybe the black wire is ground - check and see where it goes and make sure it’s not unscrewed from the body wherever it’s attached...just a thought.
  • Ahh thankyou! The relay was just wired the wrong way around, we now have fuel pumps! Car still isnt starting though 😑
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