944 Fuel Level Sender

I’m still fighting issues with the gauges on the 944.  Even though I have posted it for sale, I continue to try and perfect the car.  For some reason, I just don’t think it will sell for what I’m asking for it and I like it too much to give away, so I keep fixing (or trying to fix) the issues that remain.

The left side of the cluster seems to have a problem; the temperature gauge and the fuel gauge are just flaky.  One will work for awhile, then the other, then both, then none.  It’s a little annoying, the temperature gauge makes me nervous, and the fuel gauge is just impractical.  At least the odometer is working now so I can just fill it up every 200 miles or so.

I have now verified that the fuel level sender is functioning properly and is not the issue.  I took the whole thing apart, cleaned it, and tested it.  This is how I did it.

First you will need to unsnap the carpet that is lining the trunk area and pull it back to reveal the fuel level sending unit access.  Depending on how often this was an issue, there may or may not be a cover over the sender, and it may or may not be easy to remove.  Mine was super easy to remove…..maybe that’s a sign.

This was taken after completion, my electrical handiwork is evident. The connector broke during disassembly.

To test the sender, you will need to test the resistance between the two poles on the top.  Remove the electrical connector and use an ohms tester, I used a fluke meter, to see if the resistance is proper.  Use the information on Clark’s Garage to see if it is correct.  Of course, this is assuming that you have an idea of how much gas is in the car.  You could always fill it up and test, but if you need to remove the unit, you will get gas everywhere so think about this one.

If the above test does not pan out, or you think there is a problem, you can take out the sender and see if everything is in place.

You will need to use a flathead screwdriver to remove the return line clamps.  Loosen them as much as you can and pull them off their respective locations.  You may need to turn the sender to get them off. 

I had to turn the sender to remove the hoses

Loosen the black plastic cap on top of the fuel tank, I used a pair of channel locks to loosen the cap.  This will release the sender and allow you to pull it out of the gas tank.  Be careful, there will be fuel in the sender (unless the tank has no gas in it) and it will drip out of the bottom of the unit.  Just hold it over the opening and let the fuel drain into the tank.

Now for the disassembly!  There are two small nuts that hold this whole thing together.  The first one is holding the big plastic piece in place on the bottom.  I guess this is kind of a buffer to keep the gauge from going full / Half / Empty around turns.  Use needle nose pliers to remove this nut and take off the plastic piece.

Remove this nut with the needle nose pliers

The second one holds the whole assembly together.  Also use needle nose pliers to remove this nut.  These nuts are small so be careful not to lose them.

Remove this one to take apart the sender.

Once the second nut is removed, you can pull the black plastic piece off the bottom and remove the metal sleeve that is around the components.  This will expose the inner workings of the sender itself. 

There are 2 wires on the float, and one free flowing that you can kind of see. If you got this far you will know what i’m talking about.

There are 3 guides that provide the information that the fuel level sender needs to read accurately.  The two guides on the actual portion of the sender are connected to the float and measure the resistance.  The other one I believe is the ground. 

What you want to do is make sure the float can go up and down without any resistance or any chance of getting stuck.  My float was getting stuck, so I used some 80 grit sandpaper to clean off the metal piece that the float rides on.  This allowed the float to move freely up and down without issue.

While I had this out, I made sure that the resistance being read at the electrical points was matching the points the float was at, verifying that the resistance at Empty / Half / Full were the same as the Clark’s garage article.  It is verified that my sender is reading proper resistance.

Once it is all cleaned and the resistance is verified correct, you can reassemble.  As usual, it is the reverse of the tear down, just make sure that the piece that the float rides on is in the whole for the black plastic piece.

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