Krraaaaazzzyyyy Fuel Gauge~~~wazzup ?

[greasyhandsagain]

My fuel gauge worked fine two years ago, then the Rover took a snooze, partially due to a leaking tank. OK, Ive repaired the tank, put it all back together and have a glitch. The float and arm was swinging nice and free, I reinstalled it, hooked the wires back up (pos ground) and no reading. Banged on the dash a few times my hand, and the gauge swings right up to FULL (tank is NOT full, only 2 gallons or so). Turn car off, gauge drops back to Empty, and the same thing happens again.

What should I be looking for here?

[Nium]

Short at the tank (pinched wire) or a bad sending unit.

[SafeAirOne]

I accidentally switched my wires around when I reinstalled my sender once, with similar results.

[east high]

My fuel gauge is crazy like that too, 'cept mine stays pegged at full for most of the tank then starts to bounce between full and empty more and more ferociously as the tank empties out. It starts bouncing right around 1/2 tank. It bugs. My sender is brand new too. Probably a short like Nium said.

[rwollschlager]

X2 on short or poor grounding. I had this issue with my 109, resolved short, and gauge reads properly now.

[NickDawson]

newbie thought - but could it be a voltage issue? If the truck has been sitting I wonder if the regulator is not bad? Easy to test with a multimeter.

[thixon]

I HATE fuel gauge problems. Everyone who is interested in old cars always has one thing that plagues them on every car. Mine is fuel gauge issues. I've thrown more fuel gauges against the wall than you can shake a stick at. They can all go straight to hell for all I care. Yeah, I have issues.

I have no new info here, but what I can do is agree with two of the posters above. In my experience, what you've described is most often a poorly grounded sender, or a pinch/break in the wire. That is of courese if you did'nt manage to hook up the wires to the wrong posts.

A couple of times its been the guage itself, but the issue is usually at the sender end. You can test easily enough if the sender is doing its thing with a multimeter. If it works, I'd just re-wire the whole damn circuit.

Good luck. I hope none of my poor fuel sender/gauge luck rubs off on you.

[bmohan55]

I have a positive earth fuel sender I can give you if you want. PO had it in mine (negetive earth) and it read well...but backwards.

[scott]

I have a positive earth fuel sender I can give you if you want. PO had it in mine (negetive earth) and it read well...but backwards.

bmoh gee i'm hurt. you didn't offer me a free gauge when i was whinning about my gauge going sour. but then again i'm close to if not actually the most sarcastic dude here and sarcasism doesn't seem to foster a lot of sympathy and charity.

you say yours is a posi reading backwards in a negative truck. i thought there was a little shorting thing that is done when converting a posi to neg earth that repolarize all the gauges and stuff. my truck came w/ the neg earth conversion. added a 2nd tank and didn't pay much attention to the earth of the sender. after hookng everything up using an on off on toggle i was switching the sender units. when set to the r tank it read fine set to the l tank it would read backwards. i messed w/ it and eventually both read correctly. don't know what i did.

later i busted the gauge while removing it for some stupid reason.

so does any one know this repolarization trick?

[greasyhandsagain]

Im gonna give it a little more time to see if it mends its evil ways. I seem to remember last time I used the rover (2 years ago) It was touchy and didnt like to run low, it would then flip up and down for awhile. With more gas in it it would work good. I dont know how I could have shorted anything, but Ill check the voltages and see what I got.

Not too eager to pull the tank out again if I can help it. Kind of wondering now if perhaps I have the float pinned down or something when I put the fuel pickup line back in. Will check that out tomorrow.

wow so much fun to mess with this thing again....my 99 range rover is just too reliable...2 years and nothing at all has ever went wrong!

[SafeAirOne]

...my 99 range rover is just too reliable...2 years and nothing at all has ever went wrong!

Don't worry, when something DOES go wrong on it, you'll WISH it was just krraaaaazzzyyyy fuel gauge..

[LaneRover]

The fuel gauge in my 65 109 also runs backwards. Because it was a positive truck and now is a negative ground. I look at it as a theft deterrent. Crooks undeterred by lots of levers and a starter button drive off and think they have a full tank - only to find that it s actually empty because now 'F' means "Fill the Tank"

I hope to never test my theft deterrent theory!

Brent

[greasyhandsagain]

You are so Right there! I confess, the compressor pump for the Air suspension went kaput, and I was totally amazed that I found one on ebay way way cheap, and replaced it in Minutes! such an ez repair, probably the easiest thing on the P38 one could ever hope to do.

[oestlarsen]

Glad I am not the only one. My guage is pegged on FULL at all time, even when I disconnect the wires to the sending unit. My theory was that the guage body itself somehow got in contact w/ ground in the guage assembly/housing...thus totally circumventing rest of the circut. Or something like that. I gave up last winter and will try to rewire the whole thing this year. Seems to be best option anyway.

Oh - if there is a ground connector from the sending unit - does anybody know where it goes? Assume there is black ground from the unit to somewhere...

PS - Series IIa - 1967 POS Ground
PPS - Still can't get my new dynamo to charge either :-) Suspect ground issue here too.

Carl

[bmohan55]

My ground wire from the sending unit (actually it's just a jump wire from one of the screws holding the sending unit) attaches to the frame nearby via a sheet metal screw! Hey, it works!