Fuel pump relay

Hi, Can anyone tell me how to wire up this fuel pump relay? i want to wire it to the oil pressure switch so the pump comes on when the engines turning.

 

The problem with that is as soon as you get oil pressure the relay will cut out !!

 

this is the diagram your looking for

 

Thanks but i would prefer to use the fuel pump relay that i have, the one in your pic looks different?

 

If i connect the live wire going to the oil pressure switch to 86 then the wire from the oil pressure switch to 85 and then 12v from battery to 30 and then the positive wire from the fuel pump to 87, will that work???

 

Nobody know guess i will just have to try it then and hope i don't see any smoke

 

As been said it will not work how you want you need one as in the drawing

 

I have just found this info on ratwell.com,

• oil pressure switch wire -> relay 85 | relay 86 -> oil pressure wire harness
• 12v -> pump -> relay 30 | relay 87a -> ground

The relay is the NC (normally closed) variety and cuts power to the pump when the oil pressure light come on

 

That would work but you won't be getting any fuel until the oil light goes off. Not sure how that would be if you left the van for long enough for the fuel in the carbs to evapourate, depends on whether your oil light goes off while cranking as it should. Either way I can see you might have to do a bit more cranking to get it started.

 

Thanks zed, my oil light goes out pretty quick, so hopefully it should work ok. Also it says to use a normally closed relay, is my relay a NC one?

 

yours is a N/O relay, and it has a diode fitted, so totally not what you want!!

 

No

 

Who you no-ing??

 

I was no-ing along with you but you beat me to it.

 

lol

 

The other side of the coin is that if your pump comes on with the ignition, you wait a few seconds, then the engine starts immediately as you turn the key.

 

bugger just paid 16 quid for this relay off ebay and its no good

 

the down side is, if you crash and the engine stalls an ignition fed pump still pumps fuel

 

When you put it like that...

 

This. The relay's not much good for what you want it to do.

Vehicle Wiring Products will sell you a relay with changeover contacts.