1990 Festiva Fuel Gauge bad Sending Unit

[bravekozak]

it's not insane, it's just 28ga 1ohm/inch wire, but i can't find any so that i can repair units for the forum.

FestYboy, how did you determine gauge and resistance? Did you use a vernier, then unwind and cut it for the ohmeter reading?

The only resistance wire, from Jacob's online, that's close is the 32ga Nichrome 60 (Chromel C)
@ 10.6 ohms/ft

Do you think that would work with a few extra wraps?
You would need 8 feet of it for 95 ohms.
Does anyone know how many feet of wire are wound on a standard Festiva sender?

[FestYboy]

yeah that's what i did. but that 32ga @ 10.6 ohm is WAY too high for as many wraps as we would need.

[bravekozak]

Festivas are 6 ohms full and 95 ohms empty.

One ohm per inch would require 95 inches or almost 8 feet. Correct?

How many wraps would we need?

[the_feist_in_festiva]

This is exactly what the doctor ordered! Thank you all! So which gauge should we purchase from this website?: http://jacobs-online.biz/nichrome_wire.htm

[bravekozak]

That's what we are trying to determine. What is the length of one complete wrap? + How many factory wraps do you count? I will find out what the intermediate resistances are. Usually most drivers will tolerate a little inaccuracy with a full tank, but prefer high accuracy below half a tank.

[FestYboy]

This is exactly what the doctor ordered! Thank you all! So which gauge should we purchase from this website?: http://jacobs-online.biz/nichrome_wire.htm

that's not FAIR, i've been looking for that for years!!!!!

Brave, i'll have to pull a sending unit and count the wraps. keep in mind that the ohms per inch and length in feet doesn't corrispond to the # of wraps and final sweep resistance... the #s change once you start wrapping.

[bravekozak]

Did everybody follow the revive link in post #30?

Daverham bought ten feet of 36 gauge Nichrome for $2. He used just under three feet (27.0 ohms per foot X 3 = 81 ohms). Hence the $1 fix. He alo said that the wire should be purchased in a larger quantity so that it comes in a spool instead of having sharp wraps around a piece of cardboard. 100 foot spool = $6.

His resistor board is a thin rectangle. Our Festiva resistor bars are triangular and will certainly require a much longer length. Good luck Festyboy. We are counting on you.

I am guessing, but we might need 5.5 feet of the 34 gauge wire ?

[bravekozak]

I was thinking about the winding process and how the wraps get tighter toward the end to compensate for the reduction in the swing arc when the tank is full and the float is high.

It appears that the wider spaced wires when the tank is low, tend to get worn away first (greater arm movement). The tighter windings have less wear and still transmit a resistance and a fuel level when the arm gets to that position, where it stops jumping around from no resistance to resistance.

It would be good to position a mirror underneath so that as you wind the wire into the factory grooves, you could check to make sure there is no touching underneath without having to constantly do the olympic squat or flip the resistor wire board over.

[bravekozak]

Let's have a contest. Guess the number of wraps in a Festiva EFI sender based on the picture in post #10. I guess 83. What do you guess?

[bravekozak]

According to the 1990 Festiva Car Shop Manual.

F = 7 ohms
1/2 = 32.5 ohms
E = 95 ohms

[the_feist_in_festiva]

I am guessing, but we might need 5.5 feet of the 34 gauge wire ?

Alright, I'll try that. Doesn't have to be perfect, I just want to know roughly how much gas I have I guess. And if we're wrong, we're wrong, and then WE SHOULD LET EVERYONE KNOW. I don't know why I wanted that in caps. So I just ordered 30 feet of 34 gauge wire! Because for a dollar more, I'd have 20 more feet, so why not I guess. I'd probably going to make some mistakes, lol.

[bravekozak]

You should have waited for Festyboy to count the wraps. I have three fuel pumps. I will try and open one up. Wish me luck.

[FestYboy]

they're easy to open with a small pair of pliers (2 tabs to gently peal back to allow the cover to come loose)

[the_feist_in_festiva]

So I've got my sending unit in front of me, disconnected the float from the pump, and I'm bending back the four metal bends. Now I plan on trying to break off the soldered bit? Oh wait no that wasn't necessary. I just bend off the clip that held down the wire and pushed it through the hole and it comes right out!

So I've broken off both plastic bits where the wire is wrapped around on both sides. So that's good.

[bravekozak]

Did you receive the wire already? This is going to be good. Sorry, I haven't gotten around to mine yet. I'm dealing with a miswire. My radio can only come on when I turn on the parking lights. Ooopsie. I'll figure it out.

Do you have a soldering iron? Please post pictures. Everyone will be watching your progress. We're cheering for you.