finding a live connection only on with ignition???

falling-out-with-my-car · Post by **falling-out-with-my-car** » 26 Jul 2010, 01:53

Hi, I am going to fit a 3 to 4 psi facet pump to my fuel line in my xantia 1.9 TD estate, to help to lift veg oil from the tank and pressurise the fuel line.this will also help in the changinging of fuel filters in the future by bleeding all of the air out of the system easily.

but I am a little confused as to where I should take a live lead from preferably only live when the ignition is on, has anyone any bright ideas please???

i also have an fphe that is getting so hot it is causing evapouration of the fuel inside the fphe which causes air bubbles to appear out of the exchanger, I now know that pressurizing the fuel line will stop this.

many thanks in advance

regards Nigel.

Post by **RichardW** » 26 Jul 2010, 08:34

The obvious place is to relay one off the blower / HRW section of the ignition switch - however, this I think is isolated at cranking, when you probably want the pump to continue running. You could maybe get around this by using a timer relay - but then the pump would always run on when you swtich off

What are you running your oil against? I doubt anything on the car is running hot enough to get the oil to vaporise - surely this would be around 250°C?

citronut · Post by **citronut** » 26 Jul 2010, 09:34

isn't a fuel electric lift pump usualy controled via sensors, otherwise it will be pumping all the time whilst there is a feed,

regards malcolm

falling-out-with-my-car · Post by **falling-out-with-my-car** » 26 Jul 2010, 10:44

citronut,

thats right it will pressurise the line and switch off, it wont be running constantly.

are you suggesting a permenant live?

regards Nigel.

spider · Post by **spider** » 26 Jul 2010, 20:49

My first thought is the reverse light switch wiring, as far as I am aware this is only live on position 2 not the accessory position.

I'm not sure how much current you can safely take from this circuit though, I've seen it used for a stop solenoid feed on Peugeot's (but that's milliamp's for that)

falling-out-with-my-car · Post by **falling-out-with-my-car** » 28 Jul 2010, 00:30

I wonder how many amps are drawn by reversing sensors as they connect to the reverse light lead.

spider · Post by **spider** » 28 Jul 2010, 11:23

falling-out-with-my-car wrote:I wonder how many amps are drawn by reversing sensors as they connect to the reverse light lead.

21w per bulb, so that's 21/12 = 1.75 x 2 = 3.5 amps for the bulbs, give or take a little bit.

MikeT · Post by **MikeT** » 28 Jul 2010, 11:52

IF you're concerned you might overload a circuit, feed it to a relay then you can have a dedicated power feed switched through it for you lift pump. Where are you intending to site the pump Nigel?

falling-out-with-my-car · Post by **falling-out-with-my-car** » 28 Jul 2010, 12:25

Mike T,

I was thinking as near to the tank as possible, but Lew said something about one being installed in the engine bay of a vechicle.

I'll wait and see the instructions before I make that decision. but I get the impression that most people fit them near the fuel tank.

if it was to go in the engine bay I could take a supply from the stop solanoid probably.

MikeT · Post by **MikeT** » 28 Jul 2010, 14:15

Ok, we'll wait to see what the instructions say. The engine bay would be ideal IMO.

falling-out-with-my-car · Post by **falling-out-with-my-car** » 28 Jul 2010, 17:32

Mike,

the facet pump has arrived and I thought they said it was small anyway it has a required 75 micron filter with it and two 8mm hose tails but if you use the hosetails you cant use the 75micron filter.

filtering my WVO to 1 micron I can't really see the point of the 75 micron filter.

the instructions say it must be mounted within 12 virtical inches of the fuel tank bottom, so how the heck someone managed to fit it on the engine bay I dont know, it must have been quite low down near the bottom of the bulkhead or on the front subframe. it does say use an oil pressure switch to connect to the live terminal to stop the pump operating whilst the ignition is switched on but the engine is not running, I am wondering if I can utilise an oil presure switch alreadty fitted to the xantia? as this seems to be a pretty good idea.

MikeT · Post by **MikeT** » 28 Jul 2010, 19:09

Hi Nigel,

I wouldn't worry about the pump/tank head difference, it's more a guideline IMO as just about any pump can easily work beyond their rated head distance, including the Bosch IP. On a vehicle, it has to overcome g-forces and inclines so needs a fair tolerance built-in.

Yes, the oil pressure switch would provide a welcome layer of protection, ensuring the pump is switched off when the engine isn't running. As always, it's best to use this tapped feed to switch a relay rather than feed the pump direct.

citronut · Post by **citronut** » 28 Jul 2010, 22:27

i thought the oil presure switch is fed with a ground/earth whilst ignition is on untill the engine is running, once oil presure is up it dosent it break the conection,

regards malcolm

MikeT · Post by **MikeT** » 29 Jul 2010, 10:26

citronut wrote:i thought the oil presure switch is fed with a ground/earth whilst ignition is on untill the engine is running, once oil presure is up it dosent it break the conection,

I have no idea what the feed is - as long as it switches, it can be used via a relay to control the pump activation.

falling-out-with-my-car · Post by **falling-out-with-my-car** » 29 Jul 2010, 10:55

Nope your way over my head now all of you. I suppose there are other ways to ensure the pump is off other than using a relay perhaps taking the live feed from something that is only on when the ignition is on, day-sha-voo. I'm going round in circles here...lol.

I find relays very cofusing to say the least and to rig up my conel bogey air horns I had to follow a relay diagram (very confusing).

electronics was never my best subject.

I just about understand the diagrams that came with the pump,

am I to assume that this pump runs all the time? if so it might be worth investing in some rubber mounts or making some.

I think I will go for the engine bay mounting and mount it where the primer bulb is on the xantia if I can get away with it,

the oil does seem to be rotting the plastic valves in the primer bulbs and dropping back down the bulkhead whilst the engine is running and I think this is where the air is getting in at the primer bulb but it doesent always rear its head to see air bubbles in this part of the fuel line if I fit a clear peice of line.

then again it could be an issue supplying cold oil to the tiny dieselveg H/E. and hot oil exiting faster than it can be supplied to the H/E. whatever is happenning its a relief to know that the pump will probably find the leak.

Is there an easy way that a non-elctrical wizard can do it?