Fuel Gauge / Instrument Cluster - 82
10-28-2010, 10:58 AM
#1
Rennlist Member
Thread Starter
Fuel Gauge / Instrument Cluster - 82
The fuel gauge on my 82 decided to stay on E. The sending unit checked out fine and the gauge would not move using a potentiometer at the tank connection so I pulled the pod.
I found two cut wires and one added wire. One cut wire was a ground and the other was the brake pad wear indicator. I repaired them with solder and heat shrink. The added wire goes to the fuse panel and is hot when key is on. It was attached here.
The point where that wire was connected goes to an edge connection with no terminal in the mating connector. Also, I can find no other points on the cluster that have continuity to the stud to which this wire was connected.
I cleaned and refurbished the instrument cluster and now with a full tank the gauge reads a little over 1/4. When I connect that hot wire the gauge goes to 3/4.
Anyone got any ideas of what is going on here?
Thanks in advance.
I found two cut wires and one added wire. One cut wire was a ground and the other was the brake pad wear indicator. I repaired them with solder and heat shrink. The added wire goes to the fuse panel and is hot when key is on. It was attached here.
The point where that wire was connected goes to an edge connection with no terminal in the mating connector. Also, I can find no other points on the cluster that have continuity to the stud to which this wire was connected.
I cleaned and refurbished the instrument cluster and now with a full tank the gauge reads a little over 1/4. When I connect that hot wire the gauge goes to 3/4.
Anyone got any ideas of what is going on here?
Thanks in advance.
10-28-2010, 05:29 PM
#2
Rennlist Member
Well, it could be that your fuel gauge will only register 1/4 tank when it is actually full. (That could be the maximum that the sender unit will take it) When you add the hot wire (ie a totally hot wire), it takes it to the maximum that the guage will register(ie 3/4). You might try moving the pointer on the shaft to full then driving the car see if it registers correctly from there.
Just a thought. Let us know what you find.
Just a thought. Let us know what you find.
10-29-2010, 12:17 AM
#3
Rennlist Member
BTDT.
Have you had the sender out of the tank? There are couple of things that could be wrong there. The resistance across the 2 pins on the sender (1 is for low fuel warning light, 2 for gauge) should vary from close to zero to somehwere above 70 ohms - I think mine got to low 80s. Low resistance is high fuel level. Its alos possible that the wires have dried fuel residue on them, mucking up the reading, or the slide contacts are not reliably contacting the wires. See Snakeskin's pages here for some very good pics of the sender internals.
jp 83 Euro S T 52k
Have you had the sender out of the tank? There are couple of things that could be wrong there. The resistance across the 2 pins on the sender (1 is for low fuel warning light, 2 for gauge) should vary from close to zero to somehwere above 70 ohms - I think mine got to low 80s. Low resistance is high fuel level. Its alos possible that the wires have dried fuel residue on them, mucking up the reading, or the slide contacts are not reliably contacting the wires. See Snakeskin's pages here for some very good pics of the sender internals.
jp 83 Euro S T 52k
10-29-2010, 01:40 AM
#4
Rennlist Member
Thread Starter
BTDT.
Have you had the sender out of the tank? There are couple of things that could be wrong there. The resistance across the 2 pins on the sender (1 is for low fuel warning light, 2 for gauge) should vary from close to zero to somehwere above 70 ohms - I think mine got to low 80s. Low resistance is high fuel level. Its alos possible that the wires have dried fuel residue on them, mucking up the reading, or the slide contacts are not reliably contacting the wires. See Snakeskin's pages here for some very good pics of the sender internals.
jp 83 Euro S T 52k
Have you had the sender out of the tank? There are couple of things that could be wrong there. The resistance across the 2 pins on the sender (1 is for low fuel warning light, 2 for gauge) should vary from close to zero to somehwere above 70 ohms - I think mine got to low 80s. Low resistance is high fuel level. Its alos possible that the wires have dried fuel residue on them, mucking up the reading, or the slide contacts are not reliably contacting the wires. See Snakeskin's pages here for some very good pics of the sender internals.
jp 83 Euro S T 52k
The sending unit is clean and reads about 75 ohms empty and about 3 ohms full and is linear inbetween. The "low fuel" switch works fine also.
With a potentiometer on the wires the gauge moves but not properly.
When shorting (0 ohms) the gauge wires the needle only goes to about 3/8. If the "mysterious hot wire" is connected it goes to about 3/4.
I am certain the problem is in the cluster or the connections to it.
I am deep into investigation and will post my findings.
