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Fuel gauge problem

16K views 14 replies 4 participants last post by  Philip 
#1 ·
Okay, I know this has probably been covered but this newbie needs help! I purchased my 1965 Nova about a month ago and noticed the gas guage needle at 1/4. Put gas in the car, nothing. I pulled the lead wire from the sending unit and the guage moved to full. Dropped the tank, restored my tank and purchased new sending unit. PLugged everthing up and guage still reads 1/4 on a bone dry tank. Like an idiot, I didn't think to look at the guage when I took the tank out, but like I said, with the lead off the sending unit, the needle moved to full. Could my guage just be stuck at a 1/4? I haven't put gas in the new tank because I don't want to drain it again if I have to drop the tank.
 
G
#3 ·
check and confirm the ground is clean & tight, also, run a jumper if necessarly to confirm the gauge wire is good. check those out and let us know... i haven't really heard of too many situations where the gauge was shot, 99.9% of the time it was either the sender (you indicated yours is new) or the connections/wires.
 
#5 ·
OK.... update... put five gallons of gas in....nothing:mad: Gauge didn't move. Checked my ground, good, checked my lead, good. The gauge doesn't move with the ignition on or off. It just stays in one spot. Shifty4, what exactly are you talking about with a jumper? Could you walk me through it? Not too good with the wiring stuff.
 
G
#6 ·
the wire that runs from the gauge to the sender, it runs under the carpet...

you can take a length of wire and install it on the gauge, toss it out the door and underneath to the tank... but from your post above you said you checked that wire so i guess what i said isn't necessary, unless you just checked to see if the connections were tight... i was saying to confirm the wire isn't broken somewhere... that's where the test lead would come into play ;)
 
#7 · (Edited)
Thanks for the quick reply. I see what your saying now. I will get out Thurs and try that. A couple of quick questions; I left the ground on, took the lead off and the gauge didn't move an inch. Does that mean anything? The car's wiring is questionable. I've got some kind of short going on right now where something is drawing power with the ignition in the off position. With my battery cables on, my voltage gauge shows a reading without the key even in the car. I have to disconnect the battery to keep from draining it. Takes about 3 days to total discharge the battery,
 
#11 ·
What it sounds like is that the gauge is reading resistance. The gauge works based on the amount of resistance it senses. The sure way to test your gauge is when you had the tank down to remove the sending unit and move it through it's entire range. The gauge should go from E to F with everything connected. If it doesn't, go to E then your gauge may be reading resistance. Disconnect the sender and put a Solid Ground on the sending unit wire and the gauge should go to E. If it doesn't you are getting resistance through your wiring. You can read a wire from end to end with a multimeter and it may appear good as far as continuity but it may have resistance in it due to age, corrosion, etc. You can check the sender directly with a multi meter by just reading the terminals and moving the float. Should be zero at one extreme and whatever ohms the system is setup for maybe 190-250 or something like that at the other extreme. The gauge has a normal position either full or empty (I don't recall which) but in the normal mode it should be at either E or F and when you vary the resistance to the + lead it causes the meter to move. If I'm not mistaken you can test the gauge with just by either opening or shorting it and it should move from one end to the other. If it works properly by directly testing the gauge but stays at 1/4 with the wiring connected you have faulty wiring and Shifty's run the wire out the window test will need to be performed. I know this may sound confusing, but if you google fuel gauge testing you can probably find a more detailed test procedure or if you have the chilton's it lays out a pretty good test method which you'll find to be very close to what I'm suggesting here.

Good Luck!!!:D
 
G
#8 ·
'63-'65 show the same according to a restoration part supplier i checked but there was no listing on the '62

part number 21028-1 at this site: http://chevy2only.com/chevy2only/

here's an image of the '62 cluster and the gauge appears to be the same but i can't confirm it for ya.

http://www.jollyrodder.com/ChevyII_Gauge_Cluster.php

here's a link for your wiring schematic: http://rides.webshots.com/photo/2680372130058614284cESOIS


it shows a wire off the gauge from the tank to the sender, the other wire feeds from the ignition switch. try removing the wire and check with a teat light to confirm you have power in at the gauge. if you do, take the jumper lead and test the lead from the tank sender to the gauge... also, if you have no power coming in you'll need to find out why. if you disconnect the power wire and replace with a test lead (positive) to the terminal it should then register on the gauge (providing you have no power now at the gauge.)


hope i'm helping.
 
G
#10 ·
looking at the schematic, the power wire is a milti-connected group that's feeding quite a few items. i'd first pull that wire from the gauge, turn on the key and check to see if it's powered up. might be a bad wire/loose connection ;)


check all the fuses too while yer under there ;)
 
#12 ·
Thanks for the info PDQ 71. Ran the jumper and nothing. I took my gauge cluster out and when I removed the plug on the back of the gas gauge, the needle didn't move! Took the gas gauge completely out and the darn needle is still showing 1/4 tank! So.............................. new gauge is on it's way complements of another nova brother!:hurray:
 
#15 ·
When you disconnected the sender wire and the gauge pegged to full it indicates that everything from that point forward to the gauge was working. If that wire were shorted to ground the gauge should go to empty.
The ohms of resistance used to operate the gauge was changed around the 65 or 66 model year, I am not sure of which year. The earlier gauges used less resistance then the later models. The sender and gauge would need to be matched to work properly.
 
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