Hello,

I have done a search but can't find an exact answer to the problem I'm having. My fuel gauge ranges from a reading of 1/4 tank (actually tank is physically empty) to about 1/4 tank ABOVE full (actual tank level full). That is to say that the gauge moves throughout a proper "range" but it's always reading "plus 1/4 tank" if you know what I mean. That leads me to believe that the sender unit and float are working in some capacity but somehow I need to figure out how to "zero" the gauge.

Maybe I'll paint on new markings with liquid paper!!!

No really, any ideas?

 

I hate to say it, but it's probably a bad sending unit. But before you jump into the tank, I would check all your wiring all the way from your tank to the gauge...particularly the ground points. The Haynes manual electrical diagram shows an anti-slosh module in the instrument cluster with the gauge. To isolate this, you could try a new/different sending unit without installing it by just plugging it in, then move the float by hand to see what happens.

I'm just talking ideas here, I have no experience with this and I don't know how difficult it is to access the sending unit cover on the tank. It seems like I read here awhile ago that you could cut a small access hole in the floor of the cabin to access the sending unit cover....anyone done this?

 

Yeah, it may be the sending unit but I'm not going into the tank for any reason other than faulty fuel pump. It's too much trouble for a fuel gauge. I was hoping that someone might have a unique fix to this problem. I looked through Haynes (you know, 160 ohms full tank, 15 ohms empty etc, etc). My fuel gauge works. It just doesn't know where to start and stop (on the cluster panel). Seems like there would be a simple solution. I hope there is!!

If I **** my head sideways 45 degrees it works fine. It's like setting your clock ahead 10 minutes so you can always be early. I just have to fill up when she reaches 1/4 tank!

Thanks for the feedback.

 

I don't blame you for not wanting to go in the tank, it's not very fun. I would live with the problem as well if I knew it was the sending unit. I think you can still isolate things before settling on the sending unit. Someone may need to correct me on this, but the circuit looks like it depends on a reference voltage and a varying resistance (the float) to ground to make the needle move. If the ground reference is off due to corrosion or other problems, it will make the resistance that is felt by the gauge change a little, making the gauge needle move to balance the circuit. If the ground is wrong, or the reference voltage is wrong, the indication will be shifted. It appears you can make sure your ground is good using the connector on the outside of the tank...it looks like the connector shown as "C141..." in the diagram on page 12-32.

Again, odds are that this will all check out okay. But you never know....

 

I got under the truck to check the connection today. Reading was 77ohms which makes sense since I (should) have around 1/2 tank in there.

Connections were all solid at that end.

I also switched out the fuel gauge/oil pressure gauge panel peice of the cluster display with a spare I had from another cluster unit. By the way the oil pressure gauge seems within normal range (I think they share the anti-slosh unit).

No change.

There may be some issues somewhere else or a trick-of-the-trade that I don't know about. I'll keep "messing" with it.

 

Hello,

I'm still living with this gauge problem. I will have a go at trouble-shooting this again on the weekend. Does anyone know where this circuit grounds? Also... does anyone know where the anti slosh device is located (and what it looks like). I have tons of spare parts to work with from my "parts truck" but I will not drop the tank until I'm sure I've addressed the other issues.

In summary:

1) The gauge operates through a proper range but the "zero point" is off (it goes from 1/4 tank when empty to 1/4 tank above full when full)
2) ohm reading is 77 when tank is just under 1/2 full

Any clues?