Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Fuel gauge sender/rack

Very disappointed 😔. Went to 0% after 128 miles, taking on 5.3 gallons. The only difference was that she used to be at 50% after 100 miles and then drop like a bomb after that quickly going from 50 to 31 or so and then drop to 18-11-4-0 rapidly, still winding up at about 129. With the resistor it was a consistent drop throughout, but the same results.

Wow! something wrong there. Converting to UK currency that's only 20 litres. Typically I can put in just over 30 litres now with gauge on continuous 0%.

Even before fitting resistor it was around 25 litres with same indication.

I did say YMMV but not by that much. Could it be the bad sensor connections you had before?

Guess I'll do a recleaning again and see. Dolph's 280 seems perfect with no mod.

Alright... cleaned everything AGAIN. Coated with dielectric grease after using contact cleaner. After 36 miles, she's reading 94%. Promising so far. BTW...nothing looked dirty.

Well... thought I was on 0% after 120 miles again but then it bounced from 0>4>7 back and forth for another 40 miles or so until she stayed at 0 after about 160.

If it's any concilation mine started dipping to 0% earlier than previously, after as little as 95 miles in one extreme case, but bounced back up over the next 100 miles.

Have also found a rest can have gauge reading higher. e.g. near 0% when switching off, then 31% the next day after 150 miles from full tank.

Cannot believe it's the sender resistance causing these great variations, so we are down to the bizarre display software algorithms. Will check/remake resistor connection though with proper soldered joint.

Thought I'd post this as a "possible" help for your fuel gauge issues.

Classic Instruments Sender Calibration Box

It may be worth a try. Or at least a dialog with them on your issues and see what they would recommend.

Unfortunately Dan, it doesn't seem that a simple resistance tweak totally solves the issue. This lies with how the sender resistance is interpreted by the digital display, allied to possible damping of same.

With the resistor I now hit 0% after about 130-140 miles, then bounce up into the teens, 4%...7%... and back to 0 for the next 60-70 miles (around 200) at which point she just stays at 0.

From what I gathered from their website, this device can weight, or smooth out the signal. This would give a better "average" reading and not bounce around all the time.

Richard, you've been tweaking the resistors etc and you should know what will or won't work. I just thought it may be an option for someone to try.