Z3d

Hello All. My 70 98 has a fuel gauge that has not worked since I got it. I need to fix it as it drinks gas and I don't wanna get stuck on the side of the road. I did a quick check at the tank and noticed a orange wire that was broken and flopping from the top of the tank (Where does this wire go?).

I figured this was the issue and decided to drop the tank. I got one strap loose but the bolt on the other side just spins . Before I cut the strap, does anyone know if the straps can be easily purchased (Same as Cutlass or 88?)?

Most parts for this car seem to be rare so I just re-installed the bolt that I got out and came for help.

agtw31

dont pull your tank just yet.

look for a wire running from your sender to spot on the frame in front of the tank.
that is your ground wire.

if you dont see one,the wire you have laying there is your ground,just make a clean spot on your frame or anywhere there is clean metal,and screw it back on.

Z3d

OK thanks. I looked when I 1st found the wire and didn't see any obvious spot where the wire would belong. Because it was orange I figured it wouldnt be a ground. I will take your recommendation and see if I get it going tomorrow.

agtw31

look for a ground wire.if you find it,then you might have to pull the tank and reconnect that wire to the sender

jaunty75

On my '67 Delta 88, there are two wires coming from the top of the tank, one orange and the other black.

The ground wire is black and it goes forward of the tank and attaches to a screw mounted just above the tank on the frame. The orange wire is the "hot" wire, and it goes back toward the license plate bracket and connects to another wire inside the trunk that then goes all the way to the dash gauge.

First of all, where is your gauge pointing now? If it is pointing at "Empty", then the wire from the gauge to the sending unit in the tank is grounded. If it is pointing at "Full" or more than full, then this wire is not connected to anything (open circuit). I'm going to guess that this second possibility describes your situation as that loose orange wire you have should be attached to a wire in the trunk that runs to the gas gauge, and yours isn't attached.

Look in the trunk just forward of the license plate area for a cluster of wires (there will be several, such as for the back-up lights and license plate illuminating light). One of these is probabaly just terminated or broken. If you find such a wire, you might first check it with a volt meter to make sure it isn't hot with the key on. If it's not, it's probably the wire that your orange wire attaches to. If it is not hot, try grounding it with your ignition on and then look at the gas gauge. If your dash gauge is working properly, grounding this wire will send the gauge to "empty." The sending unit inside the tank is a variable resistor with the resistance varying from zero (tank empty) to 90 ohms (tank full). If this wire is not attached to anything, then it is an open circuit (infinite resistance), and the gauge pointer should be pegged at full or beyond. You don't say if your gauge needle moves at all or if it is just stuck somewhere. If it is stuck at "Full" or beyond, then reattaching this orange wire to the wire in the trunk it is supposed to be connected to might get your gauge working.


I did drop the tank on my '67 Delta, and the straps, while covered with surface rust, were quite useable. I cleaned them up with a wire wheel on my drill and then repainted them. They're good as new. Don't worry about cutting out the long bolts that hold them on on the rear side. They're easily replaced from the local Lowe's or Home Depot. If you do need new straps, you can probably get them from a local auto parts store, or I've seen them online at inlinetube.com.

Parts for this car will be more rare than for the Cutlasses, but they should be findable.

While I had my gas tank down (I was trying to fix my non-working gauge as well), I cleaned it and repainted it. It was in very good shape for being 42 years old.

I wasn't able to fix my gas gauge as the sending unit was broken and could not be fixed. I have the tank back in the car so I can drive it, but I'm on the lookout for a replacement. I've seen two NOS units on eBay in the last few months, but I haven't been able to win the auction!

Z3d

Jaunty75, thank you for the very thorough and informative reply! My gauge is actually stuck just below the half tank mark. I really hope the senidng unit is not hosed. Now that I know exactly where to look, I will track down the wiring and see if I can get it to work or root caused.

Worse case, the tank must be dropped. I am a lil worried about cutting the bolt thats giving me trouble as I kow my cutoff wheel will throw lots of sparks and this is right at the tank. I would hate to burn down the car . Any best practices or advise on removing this stuborn bolt?

jaunty75

This is a little harder to diagnose because it suggests that your gauge wire is partly grounded, which doesn't make sense if your orange wire is not attached. That suggests open circuit and a gauge pointing at "Full" or more.

This suggests that the dash gauge is broken in some way. You really have to come at this from two ends. You have to verify that the dash gauge is actually working properly. You need to find the wire at the back end of the trunk that comes from the gauge. There should be a plastic connector that joins this wire with the orange wire coming from the tank. Open this connection (it's probably open already since your orange wire is not attached to anything) and stick a paper clip or something like that into the end that comes from the gauge, and, with the key in the "on" position, ground this wire. The gauge should move to Empty. When it's not grounded and the key is on, it should move to Full. If it doesn't move like this, you have a problem with the dash gauge itself, such as a stuck pointer or a broken wire between the trunk area and the gauge. You would at least want to get down under the dash and look up under there to see that the gauge wire is actually attached.

If the gauge does work as I've just mentioned, then the problem is at the other end and involves the sending unit. The only way to repair this is to take down the tank, which I found to be far less of a job than I thought it would be. You don't really even have to get all the gas out. Get it down to two or three gallons and then remove it. The real issue is the extra weight of the fuel, not the possibility that it will spill. There are only a few openings into the tank, and they're small, and no gas is going to spill out if you lower the tank carefully and then move it out from under the car.



Why not just use a hack saw? It's not a very thick bolt (at least, it wasn't on my car). Or just a drill to drill into the bolt from the side? The job doesn't have to be pretty. It just has to get that bolt out. You're going to put a new one in, anyway.