Electric fuel pump wiring (Novice alert!)

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nehpets13
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Electric fuel pump wiring (Novice alert!)

Post by nehpets13 »

Hi all,

Fitting an electric fuel pump to mu 2.0 Aircooled and pretty much know where to fit etc

But! Wiring says to wire to oil pressure switch which I don't have so where (in simple laymans terms lol) is the best and easiest place to wire it to?

Any info and advice greatly appreciated

Cheers

Stephen
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Mocki
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Re: Electric fuel pump wiring (Novice alert!)

Post by Mocki »

You don't have a oil light ??

Anyhow I would wire it via a relay taking its signal off the fuel cut off solenoid on the carb if it was me , fused in the main feed obviously
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bigherb
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Re: Electric fuel pump wiring (Novice alert!)

Post by bigherb »

The best and easiest way is to use a Tachometric fuel pump relay although the most expensive at about £20
Image

Or if you find the oil pressure switch.
Image

Or you can use the alternator but if the alternator stops working the fuel pump will also stop.
Image
Last edited by bigherb on 20 Jan 2015, 09:39, edited 2 times in total.
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RedGus
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Re: Electric fuel pump wiring (Novice alert!)

Post by RedGus »

Those are very useful diagrams, bigherb. I like the elegant simplicity of using the starter feed to get power for the pump while the engine is cranking, before it starts.

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Re: Electric fuel pump wiring (Novice alert!)

Post by AdrianC »

Mocki wrote:You don't have a oil light ??

Indeed. Job one, surely, is to undo whatever bodge removed the oil pressure switch.
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Re: Electric fuel pump wiring (Novice alert!)

Post by RedGus »

I can't believe that someone would actually have taken out the oil pressure sender. Don't you think that the OP meant that he didn't know where to look, or that he wasn't aware that there was a sender that worked the warning light?

Actually, on second thoughts, I can believe that some idiot previous owner would bodge everything they possibly could, because it's usually the case. But, really, why take out the sender and jam a big bolt in there? Or leave an open hole! :shock:
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bigherb
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Re: Electric fuel pump wiring (Novice alert!)

Post by bigherb »

RedGus wrote: Actually, on second thoughts, I can believe that some idiot previous owner would bodge everything they possibly could, because it's usually the case. But, really, why take out the sender and jam a big bolt in there? Or leave an open hole! :shock:
Actually it is quite common when people fit oil pressure gauges they seem to think they will notice the gauge drop to zero rather than a light come on.
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nehpets13
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Re: Electric fuel pump wiring (Novice alert!)

Post by nehpets13 »

Thanks bigherb for the diagrams

Very helpful and most useful, ta very much.
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Re: Electric fuel pump wiring (Novice alert!)

Post by waltraud »

Very helpful. Im doing similarly but for a petrol/lpg van. Can i ask if i want the pump controlled via a switch rather than starter (only need petrol some of the time) then it would just need a switched fused live instead.....to operate the relay but the main power coming from the main fused live connection?
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Re: Electric fuel pump wiring (Novice alert!)

Post by Mocki »

Just take the feed from the petrol switch off solenoid you are replacing so the LPG control switches the petrol pump on ....simples
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Re: Electric fuel pump wiring (Novice alert!)

Post by ajsimmo »

Mocki wrote:Just take the feed from the petrol switch off solenoid you are replacing so the LPG control switches the petrol pump on ....simples
Bear in mind that this set up (ie using the yellow wire to switch petrol ON) will leave you unable to run on either fuel should the lpg system fail (eg fuse blown and no power to switch).
Better to wire the petrol pump via a 5 pin relay so it defaults to normally on (centre pin), and the blue wire from lpg switch (to gas shut-off solenoids) is used to switch the relay OFF when running on gas. This way, even if you lose power to the lpg, you can get home on petrol, and if the petrol pump switch off system fails, you drive normally on gas, but with your petrol pump making the usual racket when you pull up in traffic, but not doing any harm as the petrol shut-off solenoid is doing it's job.
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waltraud
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Re: Electric fuel pump wiring (Novice alert!)

Post by waltraud »

Thanks Andrew. This sounds complicated, would another option be to have a switch on the dash? Or would you be able to explain what connections to what on the five pin relay? Ill get a five pin off ebay, have ordered a posiflow pump n bits.....
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Re: Electric fuel pump wiring (Novice alert!)

Post by mgbman »

I am looking for a tachometric fuel pump relay as bigherb advised. Part no. 321 906 059 D . Ebay new ones are £38 which is quite a lot.

Also bigherb's wiring diagram is excellent, but as a novice what is meant by Coil Pin 1 and Coil Pin 15 are they fuse box connections? or to the coil?

So, I have the correct facet pump, fuel hose, filter, clips, wire and inline fuse. Now need the relay.

A question about the correct fuel hoses for ethanol/petrol fuel I got new cotton braided hoses from A H Schofield with DIN 73379 printed on them, are these better than R9.

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bigherb
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Re: Electric fuel pump wiring (Novice alert!)

Post by bigherb »

Heritage have them cheaper on Ebay.
http://www.ebay.co.uk/itm/MK2-GOLF-Fuel ... 5403e4f92e" onclick="window.open(this.href);return false;

Coil pins are the ignition coil terminals.
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Re: Electric fuel pump wiring (Novice alert!)

Post by mgbman »

thank you bigherb. saved me money. Is the VW Heritage one a tachometric relay?

The connections to the coil, as I understand it then, relay pin 1 goes to the coil and so does relay pin 15. But where on the coil do I connect the wires?

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