The Lotus Grand Tourers

Bit by bit I am replacing my gauges with Stack gauges as they turn up cheaply on EBay, I have just got hold of a fuel gauge an have tried fitting it but due to the resistance range of the sender the presets it has wont work. There is a self calibration on it but it means that the tank has to be empty and at this moment I don't want to drain her. Other than removing the sender unit has any one any idea how I can set my new gauge?

Does any one have a spare sender unit out of tank I could either borrow or buy from them, as I may try this route to set it up.

Or does anyone know what other vehicle it is off? It looks similar to a land rover seriese 3

MrCoolA wrote:Bit by bit I am replacing my gauges with Stack gauges as they turn up cheaply on EBay, I have just got hold of a fuel gauge an have tried fitting it but due to the resistance range of the sender the presets it has wont work. There is a self calibration on it but it means that the tank has to be empty and at this moment I don't want to drain her. Other than removing the sender unit has any one any idea how I can set my new gauge?

Does any one have a spare sender unit out of tank I could either borrow or buy from them, as I may try this route to set it up.

Or does anyone know what other vehicle it is off? It looks similar to a land rover seriese 3

Is there no way around this?

Have you got the ohm range of the sender sensor?

I think looking at previous post

here the equivalent figures were:
5.7 empty
53.4
74.0
101.5
170 full

Having read the set up info for Stack, I can only see you being able to do this when the tank is empty(ish). Also, I would have to re-measure the sensor range as your last post doesn't fit in with the presets listed, although one is close but I am unsure how much "play" you have. I'm hoping Fueltheburn may have some info to interject from his recent non standard gauge set up.

I feel your pain on this Jerry

Most modern gauge don't like the excel sender unit as it has a strange resistance range. And the resistance goes in the wrong direction for most guages

Options as I view them.
1. Modify the resistance to work in a greater range. I have a plug in module that will do this for you - it's basically a sophisticated potentiometer. I can send this out to you if it helps. If it works, you just pay what I did for it. If not, send it back to me. Ethel is off the road for now so it's no worry to me.
2. Find a sender that has a 290 - 0 ohm resistor range and fits the tank.
3. Build a hybrid sender using the float and arm but with appropriate circuitry.
4. VDO dip type sender. Works in the correct direction. Correct range of resistance for calibrating the guage that you have. You can calibrate externally and has a baffling effect. You just need to select the correct height.

Best place to look for the senders is Merlin motorsport.

Either way, I suspect you may end up pulling the tank. I had a ton of fuel cans, disconnected the fuel rail feed and shorted the pump to empty the tank.

Thanks gents. I thought it would be a hassle but have given me something to think about. Kieran thanks for the offer I will let you know.

Hawaiis0 wrote:Having read the set up info for Stack, I can only see you being able to do this when the tank is empty(ish). Also, I would have to re-measure the sensor range as your last post doesn't fit in with the presets listed, although one is close but I am unsure how much "play" you have. I'm hoping Fueltheburn may have some info to interject from his recent non standard gauge set up.

The readings I quoted were from a post on this site so presumed they were correct Have found a Fuel Gauge Wizard (Gas Gauge Wizard) petrol, diesel, lpg etc. MK2 which I presume is the box you refer to Kieran?

Do u guys know what the resistance is meant to be at manufacture?

fueltheburn wrote:I feel your pain on this Jerry

Most modern gauge don't like the excel sender unit as it has a strange resistance range. And the resistance goes in the wrong direction for most guages

2. Find a sender that has a 290 - 0 ohm resistor range and fits the tank.
Best place to look for the senders is Merlin motorsport.

Either way, I suspect you may end up pulling the tank. I had a ton of fuel cans, disconnected the fuel rail feed and shorted the pump to empty the tank.

Is this resistance range for real? 290-0 ohm? or is it 90-0? Is the 0 Full or empty? I can deal with a gauge that has a broad-ish range and gets the gauge moving through most of the fuel range in the tank.
Thanks.

I didn't just pluck those numbers from the air. The digital guages have specific requirements. The Stack guages are compliant with around 4 different ranges, whereas my one is a royal p.i.t.a and requires a modifying circuit to get it in the range of 290-0 ohms or 510-0 ohms which is mainly GM or yankee cars.

Its a very specific problem for specific guages.
I haven't heard but i'm guessing you have sorted this now Jerry?

fueltheburn wrote:I didn't just pluck those numbers from the air. The digital guages have specific requirements. The Stack guages are compliant with around 4 different ranges, whereas my one is a royal p.i.t.a and requires a modifying circuit to get it in the range of 290-0 ohms or 510-0 ohms which is mainly GM or yankee cars.

Its a very specific problem for specific guages.
I haven't heard but i'm guessing you have sorted this now Jerry?

No haven't got any further with it, I have a spare sender unit which I intend to wire up to a 12v supply and look at the resistance then wire the gauge out side the car and try programming it.

For my clarity, the 290-0 is for the OEM sender unit in the tank correct? And the VDO gauge matches this. Sorry, fuel senders are a newish realm for me. I replaced the one in my boat a few years back with a universal replacement and it worked great. Seems I may have just gotten lucky that day.

The VDO sender in later post 86' excels is a particularly strange beast. Its scale works the opposite way around to most senders including the smiths gauges of earlier models.