1998 scarab 29
New Livorsi gauges. Fuel doesn't work. How do you test the sending unit? Need some what extensive instructions. Have multi meter understand what ohms are but don't know what setting to test on and what type of resistance numbers should I be gettimg

try old guage with jumpers and see if it functions, does needle move when power applied. may be simple loose wire. senders are normally 0-150ohms, go slow and steady up/down. jumping could be bad sender, no reading check for grounding. isolate sender wire from sender and guage and ohm it also, check it to ground and ensure grounding of tank. your problem will likely be at guage panel.

So your saying it a ground behind the Dash? I have a new volt gauge that absolutely spikes full bore when the motor is on off. Now it did work just started doing this but the gauge reads higher than the other when no key is one

ground at the dash and ground at the tank. if you disconnect the wires at the sending unit and turn key on, you should see gas guage go to full and back to empty if you touch sender wire (pink?) to ground and remove it. if no guage movement, it isn't sender.

30 too 230 ohms measure the top plate to the center nut . push the float up and wait 5 sec then down and wait 5 sec. way to check the gauge take the wire going to the nut and touch the top plate with it. see if the gauge moves.

did you replace the sending unit also? if so and it is a tube version (without float) sounds like the sending unit needs calabration, it is in the instructions (use the instructions for the calabration technique) with it and requires a jumper wire for a moment between the inputs of the unit ...after you put it into the tank to tell it what it needs to know (this happened to me when I switched out my gage and sending unit) hope this helps also if you didnt change the sending unit...the gaffrig sending unit works with the Livorsi and was less expensive than the Livorsi unit, just my experience

What was the original gauge ohm range? 0-90 or 240-33? Did you replace with same ohm range?