View Full Version : Gas Gauge problem


1968396
Nov 4th, 07, 02:02 PM
Just completed a coversion from standard dash gauges to console gauges with tic toc tach on my 68 camaro big block with four speed. Everything works as should with the exception of my fuel gauge. :confused:

I followed the instructions with the conversion kit but got a little confused on the part about rerouting the sending unit wire. I did remove the tan wire from the back of my speedometer cluster and ran wire supplied from new wiring harness to what I thought was the rear body connector ( if anyone has a picture of this connector it would be greatly appreciated)

Also I am not sure how the low fuel indicator may play a part in this problem. I do not have this option but I am wondering if you have to reroute some wiring to make gauge work without this option. Any pictures of working console gauges wiring for my model without low fuel indicator would also be greatly appreciated. I have wiring diagram supplied in kit but not real clear on it.:sad:

Any help or advise would be greatly appreciated.

Thanks 1968396

JimM
Nov 4th, 07, 03:24 PM
The tan wire is the one. It should end up at the sender terminal for the fuel gauge.
What does the gauge do?
If it goes way past full, the wire isn't connected right or to the right place.
The rear body connector is just at the top of the drivers side kick panel.

1968396
Nov 4th, 07, 03:38 PM
Gauge will not do anything. According to what you told me about the connector I have the right connector and have put the wire where it should go. You mentioned it should go on the sending unit side, with the terminals suppplied in the kit the wires will only go one way on the back side of the gauges. Should the tan wire have power on it? It does. Thanks for the reply.

dbx1969
Nov 4th, 07, 05:24 PM
Gauge will not do anything. According to what you told me about the connector I have the right connector and have put the wire where it should go. You mentioned it should go on the sending unit side, with the terminals suppplied in the kit the wires will only go one way on the back side of the gauges. Should the tan wire have power on it? It does. Thanks for the reply.

NO! The sending wire (tan) is only transmitting Ohms from the sending unit in the tank. An Auto Meter fuel gauge is a 90* gauge (from E to F) and "reads" or translates Ohms to determine your fuel needle reading. Do you have the trunk junction clip connected? This is where the tan wire from your old cluster gauge meets and is clipped into the one coming from your tank/fuel sending unit.

JimM
Nov 4th, 07, 05:31 PM
If you were to read voltage to ground on the sender terminal of the gauge, you would read voltage, but it's coming from the gauge, not the sender.

Double check your connections.

Check user "click" profile, his web-link has some pics of the back of the console gauges, that may help.

1968396
Nov 4th, 07, 05:48 PM
with key turned on I read 7 volts to ground on the tan wire connected to gauge and on the pink wire to ground I read 12 volts.

JimM
Nov 4th, 07, 07:10 PM
where is the gauge needle? empty? past full? somewhere in netween?

1968396
Nov 4th, 07, 07:35 PM
It stays on empty filled car with gas just to make sure.

JimM
Nov 4th, 07, 08:59 PM
staying on empty indicates the sender wire is grounded, or the gauge is not properly powered.

Take the sender connection off the gauge. Gauge should go to way past full.
If it doesn't, you've got some connections wrong at the guage.
If it does, you have a ground on that tan wire, away from the gauge.

SolidLifters
Nov 4th, 07, 09:22 PM
Hate to jump on somebody else's thread, but I've got a similar problem.

I converted (a couple of years ago) to in dash tach, which took the place where the gas guage was on my '69. The gas guage is now in center between new tach and speedo. It's been long enough that I don't exactly remember the conversion, but the gas guage has never worked and it was new, along with the sender. The needle stays way past full.

The guage is unmarked but has three prongs. The center one, which is to the top has a ground wire hooked to it. The left has a 12V and the right has a yellow. I believe the old guage worked, and also believe this plug was on it, but it may have had a splice by a previous owner that would account for the yellow wire instead of the beige.

I've got 12V between red & ground, but nothing with the yellow. Switching red to other side of guage where yellow plugs makes no diff............. guage still reads at about 3 oclock (way past full). What I don't understand from the above post is that with ONLY the red and ground connected, the guage goes way past full, and connecting the 3rd wire makes no difference. Maybe the problem is that I don't understand the feed of the circuit.

Sounds from the above post like I should have a voltage reading between the yellow (which should be beige) and ground, but I don't, so I guess I'll trace the yellow back to it's source if I can get my fat self buried in the floor deep enough to see under the dash.

That all having been said, are the wires positioned correctly on the guage??? Red to left, black to top/center, beige or whatever to right? (I'm describing them from actual side of the car)

dbx1969
Nov 5th, 07, 09:28 AM
The needle stays way past full. [quote]
The guage is unmarked but has three prongs. The center one, which is to the top has a ground wire hooked to it. The left has a 12V and the right has a yellow. I believe the old guage worked, and also believe this plug was on it, but it may have had a splice by a previous owner that would account for the yellow wire instead of the beige.

I've got 12V between red & ground, but nothing with the yellow. Switching red to other side of guage where yellow plugs makes no diff............. guage still reads at about 3 oclock (way past full). What I don't understand from the above post is that with ONLY the red and ground connected, the guage goes way past full, and connecting the 3rd wire makes no difference. Maybe the problem is that I don't understand the feed of the circuit.


There is a ton of information on this site about this type problem. Yes, it is usually a simple matter of understanding the circuit. If your needle stays "way past full", you've got a good start. Check the trunk connection, junction, and then use an Ohm meter to check the connection from sender to trunk...and then from sender to gauge. It will dawn on you which/what is not working ...or making sense.

1968396
Nov 7th, 07, 07:03 PM
Figured I would let everyone know the outcome of the problem I had with my fuel gauge. Turns out the stud that the tan wire connects to from the sending unit was grounding on metal and grounding the gauge itself. That is what caused the tan wire to read voltage when it should not. Thanks for everyones help you guys sent me in the right direction.

SolidLifters
Nov 7th, 07, 07:40 PM
staying on empty indicates the sender wire is grounded, or the gauge is not properly powered.

Take the sender connection off the gauge. Gauge should go to way past full.
If it doesn't, you've got some connections wrong at the guage.
If it does, you have a ground on that tan wire, away from the gauge.

I'm confused here. If "staying on empty indicates the sender wire is grounded, or the guage is not properly powered" and then "if it goes way past full you have a ground on that tan wire away from the guage", seems like a contradition.

Sorry I'm not following here. One problem I have is that I don't know how the guage works. If it's got 12 Volts to the guage, and a ground to the guage, and that makes it go full, or past, how does hooking up a 3rd wire make it read less? Admittedly I'm electronically challenged, so logical paths become more difficult.

JimM
Nov 7th, 07, 08:16 PM
No contradiction at all.

Sender wire at gauge = ground = empty.
Sender wire at gauge = 90 ohms to ground = full
Sender wire at guage = open = WAY past full.

If the gauge reads empty, and you take the sender wire off and the gauge goes to way pas full, that tells you the guage is fine. The sender wire is grounded somewhere. Removing the sender wire removed the ground and the gauge responded.

There is a sticky post at the top of electrical called "Electrical Basics" There is a lot of good stuff in there, including a couple of papers on troubleshooting the fuel gauge circuit.

dbx1969
Nov 7th, 07, 08:20 PM
I'm confused here. If "staying on empty indicates the sender wire is grounded, or the guage is not properly powered" and then "if it goes way past full you have a ground on that tan wire away from the guage", seems like a contradition.

Sorry I'm not following here. One problem I have is that I don't know how the guage works. If it's got 12 Volts to the guage, and a ground to the guage, and that makes it go full, or past, how does hooking up a 3rd wire make it read less? Admittedly I'm electronically challenged, so logical paths become more difficult.

Have you actually checked the trunk junction connection? It may need to be cleaned, but unplug and check for corrosion/dirt. In your case, your gauge is reading way past full, right? I'm not sure how/why Jim worded it that way, as it might be confusing...but if your gauge WAS working properly...and you disconnected it at the trunk (for instance)...your gauge will read way past full. This is why I'm suggesting investigating that trunk connection. And then, if you're satisfied that's OK, run a 18g wire from that trunk connection (outside the car) and directly to the gauge and see what happens. This will assure you that there's no broken connection from the trunk and along the inside/body of the car on its way to the gauge. Lastly, if that doesn't work...pull the tank and make sure the sender wire is connected properly. For your situation, this is the order/way I would check it.

SolidLifters
Nov 7th, 07, 08:28 PM
Thanks to everybody that responded. That gives me something to work with. I've got 3 cars doing the same thing now. Can't remember when Camaro started it, '60 Corvette has done it every since I sent the cluster off and had it restored, and BB. Biscayne just started on it's own last week after it's been working fine since I've owned it. I think I've got a gas guage gremlin in my garage.

dbx1969
Nov 7th, 07, 08:39 PM
Thanks to everybody that responded. That gives me something to work with. I've got 3 cars doing the same thing now. Can't remember when Camaro started it, '60 Corvette has done it every since I sent the cluster off and had it restored, and BB. Biscayne just started on it's own last week after it's been working fine since I've owned it. I think I've got a gas guage gremlin in my garage.

Don't feel bad, this is one of the most common and frustrating little problems with these cars. But at least it IS a little problem...that is usually, easily solved once you "get it" while trying to figure it out. I scratched my head more than a few times when I first dealt with mine :).