Wiring a relay to an electric pump

[paco]

Hi there,

The topic says it all. I'm currently trying to find out how to wire a relay to an electric pump to make it stop when stalling.

The thing is that I'm stuck ATM.

Has anyone experimented this on his K10 car?

Cheers

 

[Enuo]

An adjustable pressure switch on the fuel line might do it?

 

[paco]

Don't know to be honest.

So far this is the least of my worries as this is a low pressure fuel pump suitable for carbs.

I'll try to find pics as soon as possible.

 

[Enuo]

If it's low pressure, the needle valves in the float bowls should be enough to stop the fuel flow, unless you're worried about when its upside down, but I think you get valves that close based on orientation for that.

 

[paco]

ok thanks for the info.

Still has anyone ever wired a relay to an electric pump and if so how difficult was it?

 

[Enuo]

ok thanks for the info.

Still has anyone ever wired a relay to an electric pump and if so how difficult was it?

Its pretty easy, depending on what conditions you want to be met before the relay switches on?

 

[paco]

Nothing much. I just need the relay to switch on on ignition and to cut off the pump when the engine is off (stalling).

As far as I know, a standard bosch-style relay has 4 or 5 numbered leads. Specific ones will have 6 or more.

It's all about wiring the whole set right!

Help needed please!

 

[Enuo]

when the engine stalls, ignition is still on though. You can have it come on when the ignition is on and turn off when you turn the key, but to turn off on stalling you need to do something a bit more special.

 

[paco]

I see what you mean! I still believe there must a a specific relay that will do the job!

 

[Enuo]

I see what you mean! I still believe there must a a specific relay that will do the job!

You would need some sort of signal to indicate if the engine is running or not. You could use a voltage comparitor, so that you only get an output when the output at alternator is higher than battery output? But then as I say, you're getting something a bit special. ECU's have software that cuts out the fuel pump, but you're running carbs. Megajolt might have the facility to do it?

 

[frank]

my k10 had an extra terminal on the alternator that only flowed 12v when the alt was actually spinning, and that was connected to the autochoke
that could be used with a time delay relay

 

[Enuo]

Well there you go then

 

[frank]

or the oil pressure switch + primer button maybe

 

[Enuo]

Or just turn the key to the off position after you stall like a sensible person?

 

[frank]

Or just turn the key to the off position after you stall like a sensible person?

the ecu controlled pump is a crash/safety feature tho eh andy, like the old inertia switch they used to fit
the alternator one was probably attached to the field coils wire, which are 0v until the alt is kicked into action by the current from the 5w dashlight bulb

 

[Enuo]

I never knew you got inertia/centrifugal switches on alternators... don't think the micra or the almera had one... and the only carb engone I've had had a mechanical fuel pump!

 

[frank]

I never knew you got inertia/centrifugal switches on alternators... don't think the micra or the almera had one... and the only carb engone I've had had a mechanical fuel pump!

nah, inertia switch on the fuelpump many cars had them fitted in the 80,s to cut the fuel in a crash, and you had to push the red button down to reset them

 

[Enuo]

Oldskool!