Rallye cluster fuel gauge problems.

[Keith09]

Was wondering if anyone can assist me with fuel gauge troubles, I've replaced regulator & now have my oil & temp gauges working but still no fuel.  I've just replaced sending unit in tank & have 50 ohms at
> sender which should be 3/4 tank or so. Ran a ground wire from sender
> to frame verified 5 volts at sender & if i ground 5 volts back there
> the needle will show full but needle only moves slightly up when
> hooked correctly. Any help would be greatly appreciated.
>
> Thanks

[CudaMoparRay]

Don't know if you have seen this thread or not but it might trigger something to help you out.
https://forum.e-bodies.org/engine-transmission-and-rear-end/4/aftermarket-year-one-ss-fuel-sender-how-to-get-calibrated/7662/

[Solarguy]

Does the sending unit have the ground strap on the fuel line?

[734406PK]

Quote:
I've just replaced sending unit in tank & have 50 ohms at
> sender which should be 3/4 tank or so.

The fuel sender range is 10 ohms full and 73 ohms empty, so at 50 ohms resistance, the gauge should indicate about 1/4 of a tank. For 3/4 of a tank you should be somewhere around 15 ohms to read correctly.

[Cuda Cody]

   @Keith09   

[Keith09]

Does the sending unit have the ground strap on the fuel line?

That factory strap is long gone but i ran a ground from the sending unit itself to the frame.

[Keith09]

Quote:
I've just replaced sending unit in tank & have 50 ohms at
> sender which should be 3/4 tank or so.

The fuel sender range is 10 ohms full and 73 ohms empty, so at 50 ohms resistance, the gauge should indicate about 1/4 of a tank. For 3/4 of a tank you should be somewhere around 15 ohms to read correctly.

Quote:
I've just replaced sending unit in tank & have 50 ohms at
> sender which should be 3/4 tank or so.

The fuel sender range is 10 ohms full and 73 ohms empty, so at 50 ohms resistance, the gauge should indicate about 1/4 of a tank. For 3/4 of a tank you should be somewhere around 15 ohms to read correctly.

Thanks for that

[Keith09]

  @Keith09   

Thanks Cody

[Keith09]

Still looking for any ones ideas on whats going on with my fuel gauge... Is there a way to do an ohms test on the gauge itself ?

[Cuda Cody]

You've done a basic sweep test on the fuel gauge and it sweeps 100% from empty to full?

https://www.e-bodies.org/videos/

[7212Mopar]

Try the clothes hanger wire trick if you have not. See the thread by kawahonda. I play with the wire a little, unplug the wire at the sending unit and push it in until it is seated good. I then poured in 5 gallons of fuel and the gauge reads a little more than 1/4 tank now. Before it was just pass empty even I got more than half tank of fuel in it. I will see how well it does once I get my car running.

[kawahonda]

Yes, you can check ohms with the gauge installed, the same way you check on the bench. Remove driver’s heat shield and plug some alligator clips to it after disconnecting it. If it’s 73ohms or higher and you KNOW that you have sufficient fuel in there, then A) your float has a leak or B) your float arm is caught at a weird angle prior to filling (try clothes hanger trick to give it a kick) due to the sender restraint tab not being perfectly optimized for the ebody tank depth. It’s either A or B at that point. A possible C) is that you didn’t test your sender before you put it and and it was DOA.

If you’re getting OHMs lower than 73 then your is correctly commicating that it has fuel. Then you need to focus on either a grounding issue, the gauge sender wire not being properly seated, or a gauge malfunction (which I would assume is rare).

That’s all there is to it!

[Keith09]

You've done a basic sweep test on the fuel gauge and it sweeps 100% from empty to full?

https://www.e-bodies.org/videos/

Yes  i did... If i pull the 5 volts off of the sender & ground it then it'll shoot right up to full

[Keith09]

I have tried the coat hanger with no results unfortunately.

[Keith09]

Yes, you can check ohms with the gauge installed, the same way you check on the bench. Remove driver's heat shield and plug some alligator clips to it after disconnecting it. If it's 73ohms or higher and you KNOW that you have sufficient fuel in there, then A) your float has a leak or B) your float arm is caught at a weird angle prior to filling (try clothes hanger trick to give it a kick) due to the sender restraint tab not being perfectly optimized for the ebody tank depth. It's either A or B at that point. A possible C) is that you didn't test your sender before you put it and and it was DOA.

If you're getting OHMs lower than 73 then your is correctly commicating that it has fuel. Then you need to focus on either a grounding issue, the gauge sender wire not being properly seated, or a gauge malfunction (which I would assume is rare).

That's all there is to it!


As it sits now it's showing 43 ohms at the sender itself so that should be enough to move the needle i would think.