1990 Festiva Fuel Gauge bad Sending Unit

[the_feist_in_festiva]

YES! THIS IS WONDERFUL WONDERFUL NEWS. I'm going to take a second stab at it tomorrow using some JB Weld, because I don't have anything else, and if that fails, I'm going to go pick up an Aspire sending unit. This is beautiful. Thank you William.

You know what, here's what I'll do, since the junkyard is literally down the street from me, lol. I'll take home a carb sending unit and mess with it and see what comes up. If it doesn't work, then I'll go ahead and exchange it for an Aspire unit. I love you all.

[william]

Iam currently. Using an aspire sinding unit in my 90 festiva all the way full reads 3/4 but is accurate
when its gets down to half and continues to be un till empty.
I thought they were the same as the festiva when i put it in there 2 years ago and thought that the arm the holds the flote must have been bent. But after reading this thread I'm thinking its probably a different ohme reading.

[bravekozak]

Wven though they both have the same resistance windings, The carb sender is spotwelded on and not held in place by stud nuts, like on the EFI one. I have never opened up a carb sender to see what's inside. Does anyone know? If you break and resolder the wire at both ends, you might get lucky.

[the_feist_in_festiva]

Now wait just a minute. Can you take the little box with the windings around it from an 89 and older Festiva and put it in a 90 and up Festiva? THIS WOULD BE GLORIOUS because there are many 89 and older Festivas around and the closest 90 I can find is at least an hour away. Please give me good news!

[the_feist_in_festiva]

I'd like to buy a working fuel sender for a 90 fuel injected Festiva if anyone has one. Otherwise I'm driving 100 miles to a junkyard that MIGHT have a working one. I'm an idiot. I hope someone has luck with the epoxy and the wires. Maybe give me some encouragement.

[bravekozak]

That is sort of what the guy did in his you tube video with a knife to the epoxy, as it was thermosetting.

[db2u]

This is folly. Impossible! I spent an hour yesterday trying to redo the wires but I cannot prevent the wires from touching each other. If they touch, the resistance is lowered and the entire thing is off. [/U][/B]

Is there any way to coat the wire with some sort of spray on flexible insulator (some sort of plastic paint?) and then after winding it, just take some very fine sandpaper to the outside, so that just the top of the winding would be conductive?

[bravekozak]

Maybe a comb is needed. For the price of the wire, I am also going to give it a shot. It will make an interesting winter project, since I don't watch junk television.

Just pull a fuel pump at the junk yard and remove the sender/float. It's just held on with two small nuts. I am certain, it's a lot less money than paying for the entire pump.

[the_feist_in_festiva]

This is folly. Impossible! I spent an hour yesterday trying to redo the wires but I cannot prevent the wires from touching each other. If they touch, the resistance is lowered and the entire thing is off. I'm sure with some tricks and some more effort I could do it, but it takes painstaking effort, which I do not have.

Still, this is a wonderful cheap way to get a relatively good working gauge, and if I just remember that halfway means empty, I'll be fine, lol. Because instead of 95 ohms I've got 50 ohms, because of the wires touching.

But I do want to buy a sending unit. Whoever has one, please contact me as soon as possible with a price! I live in Northern California!

[bravekozak]

Great news. I finally opened up my fuel level sender and two wires were broken in the middle. How convenient. The wire thickness is .008" There are approximately 90 wraps which is equivalent to 10.5 feet of wire. Each wrap is about 1.4".

So 32 ga. wire is about right. Except that the resistance of the Nichrome 60 is slightly higher than stock. Fewer wraps would be required. You only need about 9 feet of wire.

[bravekozak]

You should start with a piece of wire that has 95 ohms. I hope you have the right gauge of wire. I was only guessing because I didn't open up my sender and measure yet.
To duplicate that range, the windings will have wider spacing below half full and tighter spacing above half full. You should be able to find the half full point on your wire with an ohmeter. Good luck.

[the_feist_in_festiva]

So... I have no idea how to remedy this besides trial and error, lol. If I were trying to be smart I would maybe think... The more resistance (more wire) means a full tank. So less resistance, and lower down the wire means closer to an empty tank. So if my gauge was halfway while I was at empty, then that should mean that I have too much resistance... theoretically. Or maybe I should try measuring ohms with an ohmmeter. Or maybe I should try even less windings, because the 34 gauge wire I have is thicker than the OEM wire.

Oh again I spoke too soon, forgetting this post:

According to the 1990 Festiva Car Shop Manual.

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

The exact opposite of what I said. Does that mean I should have more wraps than I currently have?

Again here is the issue. When my tank is empty, the gauge reads halfway. So does that mean I need more wraps/more resistance, or less wraps/less resistance? Or should I just measure out a wire that equals ~95 ohms?

I believe I need more wire/more wraps/more ohms.

[bravekozak]

I just find out what the base part number is on eBay, by searching for Ford fuel sender. Then I go to Rear Counter and type in the Festiva prefix for the search BZ-9275 for all engineering levels. I then look for a search result in the F0 to F3 (90 to 93) range (EFI + non-Aspire guaranteed). That's all folks.

Does this mean that sending units from other models, like the Escort, Pinto, Fiesta, etc. would work with our Festivas?
That's a good question. Take an ohmeter with you and a tape measure. The sending unit is mounted on a couple of studs. As long as the resistance is the same (it probably is) and the float is about the same length, you will be a winner. The Festiva gas tank is so shallow and small, that the float arm will be hard to match.

Did you follow the video link in post #30?
I can't believe you did this project without an ohmeter.

[the_feist_in_festiva]

For EFI Festiva owners who have fat wallets and do not want to wind their own!

The following customer inquiry was generated from RearCounter.com

Part #: F0BZ-9275-A

This is beautiful. How? No seriously, please tell me how you found this, because I have looked and I have looked up the Mazda part number on the sending unit and called junkyards looking for Festivas and so on. I considered calling Ford and Mazda dealers and even THE PHILIPPINES, I MEAN COME ON. How did you do this?!?!

And hold on just a minute. Does this mean that sending units from other models, like the Escort, Pinto, Fiesta, etc. would work with our Festivas? If so, I am going to a junkyard right now.

[the_feist_in_festiva]

I spoke too soon gentlemen. I spoke too soon.

Now the way it sits right now, I could live with it, and know how much gas I have left, but it is really really inaccurate, and just annoying. I knew how much gas I had left because I take photos of my odometer reading every time I fill, and it was coming up on the 400+ mile mark. Nonetheless, I filled a gallon of gas in a red container and drove until it started sputtering and running out of gas. The mark was a little under halfway. So I was pretty off.

Now days before when I was installing it, there was one point where the gauge didn't even read. I bent back the soft flat metal piece and then it worked. I think they have to touch the wires/shove past them like rude rich people at a party. But that's not really relevant right now, just something to keep in mind if someone runs into that problem.

So... I have no idea how to remedy this besides trial and error, lol. If I were trying to be smart I would maybe think... The more resistance (more wire) means a full tank. So less resistance, and lower down the wire means closer to an empty tank. So if my gauge was halfway while I was at empty, then that should mean that I have too much resistance... theoretically. Or maybe I should try measuring ohms with an ohmmeter. Or maybe I should try even less windings, because the 34 gauge wire I have is thicker than the OEM wire. So I guess I'll try that. I probably won't get to that until next week though. But again, I think the advantage of using thicker gauge wire is that you don't run into the problem of the wires touching, which some say should not happen. But if it's too sparse, maybe there'll be points where the sweeping metal piece won't touch any wire? Lol. All this for a fuel gauge. Let's have someone better at this out there do this.