Yo!

Trying to get together all the info together to fit my GT cam in my mk2. There's an awesome guide in the FAQ and I've made a blanking plate from aluminum and bought a new camshaft oil seal, cambelt, waterpump etc so I'm good to go.

I've bought the low pressure facet pump which arrived today and wondering if anyone can give me any pointers.

I see info about adding a T-Piece in, I gather this is for the excess fuel to return back to the tank? The Pierburg that I've got at the moment has a fuel return line in hasn't it? So until I go weber/bike carbs I don't need to worry about this, right?

What are you guys running for safety cut out?

I presume I just need to figure out how I want the safety cut out to work and put in inline? I've read it should be no more than 12 inches from the petrol level in trhe tank, but I've seen most pictures with the pump at the back of the bay. Thoughts?

Cheers!

Edited 3 July, 201115 yr by runforrestrun

x2 on this I'm going to be in the same situation soon

x2 on this I'm going to be in the same situation soon

I'm using a Ford Sierra inertia fuel cut off switch for cutting power. It's got two small blade connectors and bolt holes to attach to bulkhead. There's a blade switch to reset it by hand. I'm puuting it behind the bulkhead protected from rain in line with the fuel pump on a switched live. Thought about putting the cutoff switch in the cab for easier access, but I don't plan on having many or indeed any shunts that will make it cut the power.

Another alternative is using the low pressure oil sender to switch a relay. Cranking will produce enough pressure to turn the pump on. Engine cuts even with ignition on so the fuel pump is halted.

Thought the mechanical Pierburg just had an inlet and outlet, but the carb has a return.

If the carb doesn't have a return use a swirl pot from a Golf Mk2.

I'm using a Huco lift pump, not a Facet so can't help you there. But I have seen them mounted over the front wheel arch too.

This is how I've wired mine in, with 3 4-pin relays, loook for the last post on this page link for the wiring diagram :)

The facet fuel pump says that it needs to be no more than 12" above the tank, but the lift pump is more than sufficiant for getting the fuel to wherever you put the facet one, hope this helps :)

This is how I've wired mine in, with 3 4-pin relays, loook for the last post on this page link for the wiring diagram :)

The facet fuel pump says that it needs to be no more than 12" above the tank, but the lift pump is more than sufficiant for getting the fuel to wherever you put the facet one, hope this helps :)

Oops, I should have said Huco suction pump. It's designed for carbs an can fit in engine bay.

eBay Huco fast road cars clicky

Only injection cars have lift pump in tank, so not found in Mk2 normally as Mk2 have a feed and return at bottom of tank.

Didnt notice the mk2 part, my bad

Didnt notice the mk2 part, my bad

Not totally bad

There's a possible solution for the 12" requirement if really can't mount the pump low enough. Fit an injection tank with a lift pump from a Mk3.

Should fit fairly easy if post 1985 Polo Mk2 with 42 litre tank.

Thanks for your help guys. I like the idea of an inertia cut out over the oil pressure switch.

If I can mount it low enough (I'll find a way) then I don't need to source a lift pump, right?

I think the pierburg has a swirl pot. Heres an old photo. That's a swirl pot, right? at bout 5 o clock from the carb.

Is it really as simple as finding a switched live, wiring in an inertia switch in series, and giving it an earth? I suppose that would mean that the fuel pump will be on all the time when the ignition is on, like the radio or cockpit fan? If thats correct, I'm not sure if I like the idea of that..

bump?

Yeah, mount it less than 12 inches from bottom of tank, so long as pipes can't be fouled by any moving parts.

I once failed MOT for a pipe rubbing on the steering arm, after replacing an inline fuel filter in the hasty pre-service. May be it was just an advisory, but the tester said he'd like to see me and the car again next year.

Dunno about running pump same time as the radio, I can turn my radio on without key in the ignition, leave it with sound muted and drain the battery over a weekend. Jump start it Monday and think who is that muttering? Then realise its Moyles or Evans or Naughtie muted. Leave it a week and it forgets it was muted, so recharging can start playing music.

There are 4 sources of current, permanent, accessory, engine-on, cranking.

Permanent is obviously wrong, but will keep radio stations and engine control unit tuning data.

Accessory is not ideal, the pump willl hum while you're sat listening to the radio at a level crossing with engine off. So you need the last two.

I suppose it's enough for the pump to turn on once the alternator is producing current, which means the engine is running, but then you need another live to prime, which is necessary to fill the carb float bowl while cranking until engine fires in case it has all evaporated.

So it needs switched live in parallel with starter motor as well as engine running signal - could be alternator or oil pressure low sender. Those two circuits can't short together so it needs two relays really, their common switched output goes to the inertia switch, from there to the pump. Fuse where it protects as much as possible of the new wiring.

Does that make sense?

Can't work out what the third relay is for. I'll have to study salty's wiring diagram again.

It's for the tank lift pump which you don't have...

And yes, that is a swirl pot attached to the Pierburg. Only use if it is metal, I would not trust a plastic one.

Edited 20 May, 201115 yr by dvderlm

I got a bit confused. My mechaniscal pump is made by Pierburg.

Your Pierburg carb has swirl pot and return, so when the float bowl is full excess pressure will return fuel to tank. No need for a T.

If you don't disturb the swirl pot by pulling pipes off, you'kl be fine. Actuall it looks metal on this screen.

Thanks for the reply.

Still not following the wiring too well though. I think what your saying is that it's not as simple as I suggested.

A wiring digram would be spot on if you were able to make one. I've tried to figure out salty's but I'm not sure why I'd need the coil to be connected to the relay and I wouldn't need the circuit for the lift pump (I'm going to mount the facet low enough so it can go it alone).

Cool, the swirl pot can stay for the moment then. That's good news. When/if I get bike carbs on I'd just replace that swirl pot with a T-Piece with fuel in, fuel to carb and fuel return. That much is clear at last. I don't know why I'm finding this so hard to understand..!

just google vw fuel pump relay diagram, all you need is a 4 pin relay with a battery feed, earth, switched live which feeds the pump and the input from the black wire on the ignition barrel.

always fit an in-line fuse from the battery and ideally fit an inertia cut off switch (fords are your best bet for these in the scrappy)

pin outs are 30 85 86 87

Edited 20 May, 201115 yr by grungeisdead

This picture's been on clubpolo for years in the bike carb FAQ but i cant remember how far i went into wiring. I recommend a relay so the pump doesn't steal power from the starter motor,to help with starting. This is essential with the bigger engines. Note Ford EFi knock switch riveted to the body,just as it was in the 2.0i Sierra.

The Facet solid state pump is up high and miles away from the tank,being by the fuse box. It is on its own - no lift pump or anything. Does just fine,even after running out of fuel.

just google vw fuel pump relay diagram, all you need is a 4 pin relay with a battery feed, earth, switched live which feeds the pump and the input from the black wire on the ignition barrel.

always fit an in-line fuse from the battery and ideally fit an inertia cut off switch (fords are your best bet for these in the scrappy)

pin outs are 30 85 86 87

Thank you for the comprehensive reply. The power sources you've detailed above make sense.

I'm really sorry but I'm just not totally clear about the relay though. I've found this one on eBay http://tinyurl.com/3npccj8 but it doesn't give me pin out numbers. What wire goes to what pin out and how do identify which pin is which on the relay? I did google 'vw fuel pump relay diagram' but couldn't find what I needed.

From the battery feed (constant live) I fit the inertia switch and fuse (I assume 5A is sufficient) in series before the relay, right?

I found this link which has helped me a bit but it describes the pin outs slightly differently.

I've bought a relay with pinouts 30, 85, 86 and 87 as you suggested.

I plan on wiring as follows.

30 - battery + w/a 5a fuse

85 - oil pressure sender - which if I've read haynes right there is two senders, I presume I spur off the low pressure switch, which is blueblack, (as opposed to the high pressure switch, which is yellow)

86 - earth (which I presume can go to the same earth as the black wire from the fuel pump

87 - to fuel pump (red wire) via inertia switch mounted to chassis

Hopefully someone may confirm or correct my plan, otherwise I will report back when I've fitted the offending item.

:)

Edited 31 May, 201115 yr by runforrestrun

So I've wired it all up and fitted it into the car, and before I fitted the pump and swapped the fuel lines, took the mech pump off etc. I thought I'd check it with my volt meter.

I can't get a current from the live like I should do.

So I must have wired it wrong? I've tried swapping the oil pressure switch wire so it's coming from the high pressure switch instead but it makes no difference. There's no voltage coming from pin 87 when the ignition is off (which I'd expect!!) and no difference when the engine is running.?

have you tried just checking if relay will switch on using a live feed instead of the oil pressure sender.

I couldnt get my relay to work with the oil pressure switch, so just usedl the black wire from the ign barrel

have you tried just checking if relay will switch on using a live feed instead of the oil pressure sender.

I couldnt get my relay to work with the oil pressure switch, so just usedl the black wire from the ign barrel

do you mean in terms of testing just take another live feed from the battery on to pin 85 and checking the output on pin 87?

I wonder what voltage the relay would need to 'activate'? I'm getting 10.6v from the oil pressure switch.

I wanted to wire it through the oil pressure switch so the pump would get power only when the engine is running, so if I bypass that what will happen?

cheers for your help once again.

yeh just get a piece of wire connected to pin 85 and touch that off the battery.

at least youll know the relay and wiring is sound!

I wanted the same as you mate, but couldnt get it working, so just use a kill switch mounted on the dash (so i can have my ignition on without fuel pump, and also fitted an in-line inertia switch (from a ford) so that if there is a large impact, the switch will activate and the pump (and coil as its powered off the same relay) will cut-out.

you could probably use your multimeter to find out what voltage is put out of the black wire from ign barrel, as that def works and compare that to your reading from the pressure switch.

good luck mush

I wonder if I could use a converter to step up the voltage from 10.6v to 12v to activate the relay. I'm going to look into that as it may be an eleant solution for both of us.

I wonder if this is the solution? http://www.reuk.co.uk/buy-200MA-STEP-UP-VO...E-REGULATOR.htm

200ma should be enough shouldn't it? The pump itself draws the current from the battery doesn't it, all the current from the oil switch does is open the relay to join the circuit from the battery for the pump, right?

But an automotive relay will energise (pull in) at about 8volts.

http://www.bcae1.com/relays.htm

http://www.maplin.co.uk/40a-relay-for-auto...plications-6436

7.2volt according to spec.

I'd suspect the J114 unit is limiting the current to the 0.3 bar oil pressure switch.

That step-up unit might do it if your relay coil resistance is similar to the maplin item. That needs 133mA at 12 volts.

Edited 31 May, 201115 yr by dvderlm

But an automotive relay will energise (pull in) at about 8volts.

http://www.bcae1.com/relays.htm

http://www.maplin.co.uk/40a-relay-for-auto...plications-6436

7.2volt according to spec.

I'd suspect the J114 unit is limiting the current to the 0.3 bar oil pressure switch.

I wired the relay in as described in my earlier post, would you say that's correct?

If the relay should still energise at a voltage of 10.6v then I won't need a step up unit.

The yellow wire was giving a voltage of 0.6v (from memory) when the engine was running, and the blueblack one was giving 10.6v.

So my relay must be faulty then?

Edited 31 May, 201115 yr by runforrestrun

Right, so I've tested the relay as grungeisdead suggested and it works fine when you put 12v constant live through it.

Interestingly, when the engine is running the blueblack oil pressure switch wire when not connected to pin 85 on the relay kicks out 11v. But when it is connected only gives out 1.3v.

The yellow oil pressure switch wire when not connected kicks out 0.2v and when it is gives 0.1v.

The result? Having the relay connected is drawing 9.7v. This also means that the oil light on the dash flashes as the car thinks there's no signal from the oil switch.

Dvderlm, any ideas? I'm figuring this out as I go along (as you can probably see) so I'm now qite comfortable with how the relay switch works and how to wire it up (I'm proud) but I'm now stumped..?