If I put in the correct relay 18, and take the proper pins out of the fuel pump plug at the rear of the CE2 fusebox , will an electric pump work as it would in a Gti ? As in, prime with key on, then run continuously with engine running? Or do I need to add any more wiring? All in a CE2 carburettor mk2 .
18 relay isnt correct for fuel pump, it will just run the pump all the time ignition on. assuming its a basic carb mk2 without an aftermarket spark ecu what you want is a kjet 8v type fuel relay, which are triggered from rev counter signal. For CE2 its a little more tricky as you have to tap another wire into the rev counter pin G1/12 or from the over-run control relay if you got one (its clipped on top of the fusebox and has a wire tapped to G1/12) then run it to fusebox pin G2/7 or you could mount your fuel relay above the fusebox, if you want to use factory pins in the rear loom for the fuel pump run pin 87 of your external fuel relay to Z/1 and it'll back feed the fuel pump fuse to power up the pump
Thanks Jon. The pump in this case is 'bay mounted . By relay 18, I meant in location 18 on the fusebox. I might just get an inertia switch from a newer car, for safety , and loop the relay for the pump into it.
ah, well its slot 12 for the fuel pump if your pump is in the bay find somewhere dry for your k-jet fuel relay or a waterproof box and put it in the bay as well. wire like so: 30 - battery via 10a fuse 15 or 86 - ignition live (coil has spare spade you could use, or various feeds on carb) 87 - to fuel pump 31 or 85 - earth 31b or 1 - to coil negative/rev counter wire
It's industry standard to use 31 as earth even though it'll work both ways . And sorry , yes, I said 18, when it's the Fuse is 18, not the relay, my bad. Thanks again RJ
Just finished plumbing my mk2 rally car for carbs. Left the GTI lift pump + wiring in, removed the pump/accum/filter assembly ran the lines through the car to a 1L swirl pot on the right hand chassis leg behing the headlight. LP facet pump takes fuel from the swirl pot bottom outlet to the carbs. Oh, and a course and fine filter in line obviously Jon Swirl pot has a siteglass (clear tube) up the side and the return to tank is T ed off the top
I know, but in vehicle wiring systems , to.DIN standards according to when I did my training , it's industry standard to use 31 as Ground. Not just on relays, in General . It's not a problem usually on relays unless you are unlucky enough to pick up one with a diode in it by accident . https://en.wikipedia.org/wiki/DIN_72552 Knowing some of the numbers makes reading wiring diagrams a bit easier and faster . .
think you're mixing pin 85 trigger earth with 86 trigger live? the earth trigger on relays can either be labelled 85 or 31. I forgot to say the live trigger can be labelled 15 or 86 on them as well though!
I know where the confusion is now . Sorry . I was talking about 31 as the number for automotive Ground, not as the number on the relay , which you are correct in saying should be 85, on the relay itself. While we're talking about the wiring , the supply to the carb heater "hedgehog", is that only live when the car is cold? It'd make a nice, fused, heavy duty supply to the pump.
Yeah that's right, certain relays have the terminals labelled 15 & 31 rather than the usual 85/86 that's the only reason I mentioned both Seems to be some Aftermaketet makes which are labelled this way. The hedgehog power is triggered by the red thermoswitch in the front flange and is only active while engine is cold, you could disconnect the red thermoswitch and see how the car drives in the winter without it (assuming car is actually drivable now) This wire goes back to z/1 on the fusebox but isn't fused, though if you were to put 12v up it this will put power to fuse 18 and switch on the fuel pump if you wired it to plug M like factory. On that note I totally forgot to mention if you use slot 12 for your fuel pump then you'll have to loose the hedgehog heater! The mk3 golf spi models get round this by moving the hedgehog relay to a holder above the fusebox, so that's a workaround if you find your carby won't run well without it
