1980s 1983 Eldorado inoperative fuel gage

[jgalin]

I'm thinking of purchasing as 1983 Eldorado with the digital instrument panel.  The fuel gage is inoperative and shows two dashed lines, the fuel range shows 0, and the fuel data panel range shows 0.  Am I looking at a complicated repair?  Also, the radio shows three zeros in its display.  Not sure what that means.  AC blows warm but I don't think it has been converted.  Any thoughts from the knowledgeable members here would be greatly appreciated!  Thanks.  Jim

[TJ Hopland]

Hopefully someone that knows these systems will be along to tell you if those specifics like the dashes mean the 'dash' is fine its just not getting a signal or if its a dash failure.

Does the radio work?  Just shows zeros all the time?  Even when its off?  Like the fuel I would think the zeros would be some sort of clue.  Its not like the display is failed its just not getting a signal or being told to display that.

Do you know all about the HT4100 engines?  Unless its a diesel which had a similarly bad reputation.

[jgalin]

I am familiar with the HT4100 engine. I have an '84 Eldo convertible and have come to accept that it is slow.  I have used the stop leak pellets to stave off issues and never "push" the engine. 

[81 BENY Biarritz]

The double dashes on the fuel level display means that the sender assembly (fuel level float sensor) is giving more than 95 ohms of resistance which usually means that the slide resistor on the sender unit located inside the gas tank has failed or corroded significantly. The other slight possibility is that the sender wire is damaged somewhere or not making a good connection at the wiring connection just above the fuel filler neck.
Unfortunately the correct replacement sender unit for the digital dash gauge is no longer available but they still make the sender for the analog style fuel gauge that was used with the base gauge cluster in the 80-85 cars. I have an 81 with the digital cluster that had the same issue and replaced my sender with the analog style and it now works again but does give some readings that aren't quite exact.  I believe that the difference between the two senders is that the digital dash sender has a longer arm for the float and may have a slightly different max ohm reading when the tank is full (95 ohms instead of 90 ohms).  The longer arm provides a more accurate reading of the remaining fuel level in the tank that would be required for the estimated "Range" value to be relatively accurate (this is why the display on the right side of your cluster is  showing zero).  I haven't put a lot of miles on my car since changing mine but have found that once the tank gets closer to empty that the display quickly goes from showing a decent amount of fuel to showing almost empty quite quickly.  When refilling at mid to full tank levels the amount on the fuel gauge does reasonably correspond to what the pumped gas amount shows at the pump. To test to confirm if it is the fuel sender you can ground one wire in the connector at the tank and see if the gauge suddenly goes from dashes to "E" on the display and then slowly counts back up to "F" and then the two dashes when you remove the ground.  I don't remember which colour wire to ground at the moment but if you want that info let me know and I will look it up again.  Hope this helps.  Dave     

[bcroe]

Yes the analog pickups would read near full for
the longest time, then suddenly drop off a cliff.
Since I actually wanted to know how much gas was
in the tank, I had to fix that. 

Basically the travel of the float needs to just
touch the bottom of the tank at one end, the top
at the other.  It is not too hard to lengthen
and bend the float arm to make that happen.  I
believe this would convert the analog pickup to
a good match for a digital display, which cannot
tolerate the analog design error.  Bruce Roe

[jgalin]

Thanks much for the great information. It sounds like there is workaround if I decide to purchase this vehicle.