What I have is a sensor with two leads that make a circuit when immersed in water instead of fuel.
The leads are at most 1/8 inch apart.
The voltage is 12-13
The sensor has 220k resistance added to it.
I need to know what coil resistance the completed circuit will be able to overcome in order to activate a relay.

 

I need to know what coil resistance the completed circuit will be able to overcome in order to activate a relay.

About 2.2 million ohms.
Except there is no such thing as a 2 million ohm relay.
What you're trying to do is called a conductivity measurement. It takes a lot more than a relay to use the conductivity of water as a switching point. At the very least, an amplifier, but it's better done with a bipolar square wave generator and then an amplifier. How are you at building oscilllators and using operational amplifiers?

 

The sensor has 220k resistance added to it.

Where? How? Please post a schematic of what you are trying to do.

ak

 

Sounds like you need an op amp comparator, lets see the circuit diagram...

 

I am trying to use a racor water in fuel sensor that has two wires to it. The sensor provides a ground signal when water completed the circuit across the tips.
I found the resistance in their literature.

 

Then post a link to their literature. Secrets don't get answers.

ak

 

Ok, let's forget it. I thought it was simple matter of triggering a relay from a low voltage ground.
The company sells a $150 part that lights an led and powers a buzzer. Obviously they want to sell those, not provide info to let me make one.
I had to do a lot of searching to find what I provided.

 

I don't think the converter is worth $150, but it's way more than just a relay.
Then again, I'm old. My sense of prices is stuck in the 1970's.