Replacement fuel gauge?

[DrWin]

Hi guys,

I've replaced my fuel gauge with a new one, because the old one didn't register the first 10L of gas I put in the car, and would move irregularly up and down in a way with some relation to fuel consumption, but not remotely precisely. It was normal operation procedure to run the car for 50-100km before any fuel consumption was visible on the gauge, then the needle would drop to 3/4 tank. After af few hundred kilometers more, it would drop down to 1/2 again and then sometime back up to 3/4 without refuelling (magic!).

Anyways, I assumed the gauge was faulty so I changed it out, when I was replacing the fuel pump.

But I get the same result. (?)
Both the old and the new fuel gauge is the delorean.eu type.

So I guess my question is: What is the best available fuel gauge?
Is anything available that will more precisely detect 1) all the fuel in the tank and not ignore the first 10 L and 2) fuel consumption in a more gradual manner than jumping between full quarters of a tank?

[Bitsyncmaster]

You should pull your fuel sender and manually move the float to see if you have any dead spots. You may just need to clean the resistance wire on the sender.

[DrWin]

You should pull your fuel sender and manually move the float to see if you have any dead spots. You may just need to clean the resistance wire on the sender.

Dead spots? Places where the plunger sticks?
What if I find any? WD-40? :D

[Bitsyncmaster]

Dead spots? Places where the plunger sticks?
What if I find any? WD-40? :D

Carfully clean the silver wire with a scotch brite pad.

[CFI]

Hi guys,

I've replaced my fuel gauge with a new one, because the old one didn't register the first 10L of gas I put in the car, and would move irregularly up and down in a way with some relation to fuel consumption, but not remotely precisely. It was normal operation procedure to run the car for 50-100km before any fuel consumption was visible on the gauge, then the needle would drop to 3/4 tank. After af few hundred kilometers more, it would drop down to 1/2 again and then sometime back up to 3/4 without refuelling (magic!).

Anyways, I assumed the gauge was faulty so I changed it out, when I was replacing the fuel pump.

But I get the same result. (?)
Both the old and the new fuel gauge is the delorean.eu type.

So I guess my question is: What is the best available fuel gauge?
Is anything available that will more precisely detect 1) all the fuel in the tank and not ignore the first 10 L and 2) fuel consumption in a more gradual manner than jumping between full quarters of a tank?

The gauge hardly ever fails. The sending unit is usually the problem. If you search on here you’ll find instructions for how to determine which is faulty: gauge or sending unit.

[Chris 16409]

It sounds like the needle is moving as the fuel sloshes around in the fuel tank. I would take the sender out and plug both of the holes in the bottom. Use a couple screws and only put them in half way. This will allow gas to slowly escape from the tube. The needle should read more steadily.

[David T]

Most fuel gauges act as you describe, not moving for a long time when full and then moving in a non-linear amount. The OEM gauge is the most accurate but not the most reliable.

[DrWin]

It sounds like the needle is moving as the fuel sloshes around in the fuel tank. I would take the sender out and plug both of the holes in the bottom. Use a couple screws and only put them in half way. This will allow gas to slowly escape from the tube. The needle should read more steadily.

This is the one that came off the car:
66090

Those holes had screws in them, I suppose that is the screws you are talking about?

I don't think the new fuel sender has those holes. (It must have something for the gas to go inside...?)

I get your point, the gas needs to be able to go in at the bottom of the sender and air must be able to flow out at the top, I suppose?
But not too fast or the gauge will be very sensitive to bumps, curves, inclines, acceleration, etc.

[DrWin]

Carfully clean the silver wire with a scotch brite pad.

Roger - is that what the big screw at the bottom does, disassemble the sender?

[DrWin]

The gauge hardly ever fails. The sending unit is usually the problem. If you search on here you’ll find instructions for how to determine which is faulty: gauge or sending unit.

Thanks, I'll look into that. :)

[CFI]

It sounds like the needle is moving as the fuel sloshes around in the fuel tank. I would take the sender out and plug both of the holes in the bottom. Use a couple screws and only put them in half way. This will allow gas to slowly escape from the tube. The needle should read more steadily.

I did this to my sending unit too. It works well.

[Chris 16409]

I thought I posted this, but I guess not. Here is a reference photo to what I mean.

66241

[TTait]

What are the ohm readings of the sender, full and empty?

T

[dmcnc]

0 - Ohms Empty / 88-90 Ohms Full on the OE sender. That's what your gauge expects.

[MrChocky]

I just installed DM's fuel gauge ECU to address the sloshing issues. Had to run power from the radio through the firewall to make it work.

I just learned too that the DPI sender (or is it the sender integrated into a pump?) has DM's ECU integrated.

[Nicholas R]

This type of fuel sender can be rebuilt to if necessary. I did this recently on a different car that uses the same style. I believe it was also a 0-90ohm resistance gauge, which after doing the math led to 40gage, ~60ohm/ft wire. You'd want to double check the wire length before deciding on a gage size but I imagine it would be close.

This fuel sender would have been around $100 bucks to replace, and I think the current DeLorean sender is a similar cost (probably more).

This spool of nichrome wire was $5 (w/free shipping on ebay), and it took maybe an hour or so to remove, disassemble, solder, reassemble, and reinstall.

6630566306663076630866309

[TTait]

I just went through this on my Chevy, and assumed that the Delorean was using something more exotic because everyone has been putting up with the reproduction units with the screws that just never worked well in my experience. I just figured there was some super rare spec on the Delorean system that was making it impossible to use a different unit.

The fuel sender may be a standard 0-90 ohm GM fuel sender, although I had thought it was maybe a 90-0 ohm sender because of previous descriptions of logic boxes that flipped the signal to work with our gauges.

If its as simple as a 0 - 90 GM style sender there are dozens of universal style senders available for this range, as well as others set up for specific depth tanks. With the universal ones there is a rheostat that slides up and down on vertical bar. You cut the vertical bar to 75% of the depth of the tank, mount the rheostat on the bar so it sits in the middle of the tank, and then attach a rod with a float on it to the rheostat that goes up and down with the fuel level.

It seems to me that even if it is 90-0 you could simply mount the rheostat to the bar upside down.

These senders are cheap, and available from amazon as well that has the worlds most liberal return policies.

This one seems to do the trick: https://www.amazon.com/Equus-9982-Fuel-Level-Sender/dp/B000N54U30/ref=sr_1_4?dchild=1&keywords=0+-+90+ohm+fuel+sender&qid=1621013974&sr=8-4

but it won't drive the low fuel light.

This one is interesting too but there is less info on it:
https://www.amazon.com/uxcell-Motorcycle-Scooter-Sensor-Sending/dp/B073GWJ56H/ref=pd_sbs_2?pd_rd_w=4TrVo&pf_rd_p=2419a049-62bf-452e-b0d0-ca5b7e35a7b4&pf_rd_r=1VBW931W4XA7VBJAAMB2&pd_rd_r=c17b00ac-4bd8-4cbd-97d3-d507b2e9865b&pd_rd_wg=5NpRF&pd_rd_i=B073GWJ56H&psc=1

It appears that the ohm range is close enough to be reasonable at 0-100 ohms - in this case it would show empty at empty, and when you fill the tank it would drive the needle a little higher than where full shows now, basically, it would go to 11. It's super cheap and a 3 wire unit which implies that it will drive a low fuel lamp. you might have to change the length of the flat arm so it trims out properly at the bottom of the tank, or at whatever level you want the fuel gauge to show zero - maybe you want the gauge to show zero when you actually still have a usable gallon of fuel to go 0 but that the beauty of it. A quick check however suggests that the fuel tank on that scooter is 7" deep and the Delorean fuel tank is 7.5" I think so that whould work pretty well as the fuel pump will probably get unhappy if the level drops below 1/2" anyway.

These things are super simple to understand, but read this completely first. Take your partially working sending unit and a multimeter and set the meter to ohms and measure across two of the wires at a time while you slowly turn the unit upside down and rightside up. IIRC when you measure red to white you will see 90-95 ohms when the unit is upside down because the float inside is at the top of the housing - like when the tank is full. Flip it over slowly and let the float lower inside and ohms will drop to zero. When the float is at the bottom it means you have no fuel. No fuel - 0 ohms, and the gauge shows empty.

Now hook up the wires to (I think) red and black. When its upside down the circuit is open and the low fuel light will be off. Let the float lower and just before it reaches the bottom you will see the circuit close. This allows the light to illuminate.

If the color codes above are correct then red is reference ground, white is the signal to the needle, and black is the ground wire going to the low fuel light which has +12 on the other side of the bulb.

Safety note: After doing these tests but before unhooking the meter its important that you hold the sender firmly in your left hand, upside down, for about an hour, or it will spontaneously explode because of the gasoline fumes inside it.

Kidding. That almost never happens.

No, I'm really kidding. I write stupid long posts that most people never finish so if you got this far I figured I'd mess with you.

Anyway, now that you know how they work you can order 1 or two off amazon if you want and try them out the same way. What doesn't work you can drop off at the UPS store or whole foods and get your money back. I'm confident that the top unit will work but just won't support the low fuel light, and I suspect that the second link will work fine with just a little fiddling.