Feeding Fuel Pump

[johniban 59 1 Cars]

hey everyone, going to look at a 205 in a bit, it doesnt start i think maybe there is something wrong with the fuel pump or the wiring,

just to rule out a couple of things im going to take my gti working pump with me,

just wanted to know if i could take the switched live fuel pump feed from the brown multiplugs near the clutch pedal and wire it straight to the pump bypassing the fuel pump relay, if it would be ok and work

also anyone know what pin on the fuel pump is the live?

[welshpug 1,737]

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also anyone know what pin on the fuel pump is the live?

 

 

yeah, not the green and yellow stripey one...

 

 

 

the wire in the brown plugs is the fuel pump feed from the relay, so taking it from there directly to the pump will do jack if the relay is at fault, as there will not be any power down it, all you will be doing is bypassing the fuse in the fusebox and several feet of wiring.

 

 

that is, IF it actually has those two brown plugs that a gti does, being originally a Carb engine I doubt it does unless its had a gti dash loom fitted.

 

 

what you need is a power probe or a multimeter, and a wiring diagram for the S2 rallye engine management

[johniban 59 1 Cars]

thanks for the reply, i got it started in the end just chucked a fuel pump in it and away it went,

 

regards to the brown mulit plug, the fuel pump feed in the 6 pin brown multi plug comes out of the plug and into the fuel pump relay. not from the relay i dont think.

 

if thats true what your saying then ive wired up my 205 gti6 on carbs wrong, i took the fuel pump feed straight from the brown multiplug to the silver top low pressure fuel pump. apparently that was the correct way to do it when i asked on here a while ago.

 

ive completely removed the original engine loom witch has the fuel pump relay attached to it.

[welshpug 1,737]

you've probably used the switched live which is in the same plugs.

[johniban 59 1 Cars]

No I used the fuel pump wire as advised, I've not tried to see if it works yet im guessing its not going to

[Anthony 1,003]

It's not immediately clear, but if you've removed the old 8v loom, what have you put in place to power the fuel pump?

 

The fuel pump wire on the brown multiplug (white #76) receives power from the tachymetric relay on the 8v loom, and goes through the fuse box to the fuel pump. Simply plugging the silver top pump in with nothing to supply it with power when the engine is running won't get you very far.

[johniban 59 1 Cars]

ahhh that makes complete sence now! ive wired it up wrong then oops, i was told it went to the fuel pump.

 

The complete 8v engine loom is now removed just the dash loom with the brown multiplugs left,

ill have to use the switched live from that 6 pin plug to power the pump

[Anthony 1,003]

That'll do for initial testing, but it's not ideal either from a safety point of view, or from pulling that much extra current through the switched ignition feed.

 

At the very least if you're going to do that, have some sort of inertia switch to kill power to the pump in a crash - I don't like them and they can occasionally falsely trigger if you hit a large pothole or similar, but a fuel feed that carries on running after a crash is a fire waiting to happen that you potentially won't be in a position to escape from.

[johniban 59 1 Cars]

that is really good advice,

any advice on where to get a feed from for the pump?

 

After the car is up and running and runs good i will fit a roll over valve into the fuel lines,

 

also im thinking of relocating the fuel pump and filter to the boot, i didnt want to as its not a stripped out track car i want it looking standard as possible from the interior and outside, so a pump in the boot would look a bit out of place,

although i have seen them mounted the under side of the boot floor witch seems a good place to mount them just incase of an accident so i may rethink me design.

[johniban 59 1 Cars]

just read the instuctions :/ says run the positive straight to the battery with a fuse, and the negative to the oil pressure switch, so in an impact it will cut the fuel.