Digital to analog dash conversion... issues?

[Esasky's85GN]

Gents,

I have recently converted my dash from the junk digital to all autometer analog guages. I pinned out all wires and everything works great!... except for my fuel gauge. I know that the digital dash fuel sending units are 0-120 ohm span... different from the normal 0-90 ohm GM span.

Here is my issue. My fuel gauge is spiked passed the "F". I used a 12V IGN wire and GND wire to power autometer gauge. I used (I think it is the right wire) a pink wire that was supposed to be the fuel level sending wire. I do need to verify that there is a ground on the fuel tank because I know that if the tank isnt grounded, it could cause this.

What my question is do I have the correct wire for the fuel sending unit? I went off a schematic that I received from someone on this site and it looked like a pink wire was the sending unit wire. Does anyone know if I am using the right wire and if not, which wire it is? Any assistance is appreciated!

Thanks,

Chris

 

[mikestertwo]

My prints show it is a "Pink" wire. Put an ohm meter on the pink wire and measure the resistance to ground and see what you get.

 

[Esasky's85GN]

That is my plan. I think I may have a bad ground somewhere. Do you have prints that you can send me via email?

Chris

 

[kenny]

Since this came up...

I'm about to be working on building an El Camino project and I plan to use the digital dash... I will be using a normal FI El Camino gas tank and sending unit... what am I going to have to do to get the sending unit to work correctly with the digital dash?

 

[mikestertwo]

That is my plan. I think I may have a bad ground somewhere. Do you have prints that you can send me via email?

Chris

I can send them to you when I get home from work today if someone doesn't beat me to it.

 

[drdave69]

I can send them to you when I get home from work today if someone doesn't beat me to it.

Send it to me also if you can.

 

[mikestertwo]

Send it to me also if you can.

Print sent to your email :smile:

 

[mikestertwo]

That is my plan. I think I may have a bad ground somewhere. Do you have prints that you can send me via email?

Chris

Print sent to your email

 

[GNVenom]

The sending units will work OK, since the zero ohm point indicates empty. On an analog sender, 90 ohms indicates FULL where the digital sender requires 120 ohms to read FULL. The effect of having a standard 90 ohm sender on a digital dash would present itself as maybe 12 gallons when the tank is topped off, as opposed to "F" on the digital display.

Conversely, using a digital sending unit on an analog fuel gauge would keep the needle pegged until somewhere around 5/8 to 3/4 full, and the accuracy would increase as the fuel level decreases. Either way, the sender becomes accurate near the empty mark.

 

[GregInAtl]

Why is my digi show accurate mph on kilos? Its funked up I think.