Fuel Gauge Problem

[ronzara]

It's me again!
Looks like when I turned the key on, my SW Fuel Gauge went straight to FULL and is staying there. I know the tank is practically empty. What might the problem be? The tank has a stock GM sending unit in it.
Remember: this is an EM car with a CR wiring harness.

Also whats the best way to wire the Amp Gauge?

RZ

[Mr.Fixit]

There are two very popular styles of fuel gauge sender. One, the ohms increases with fuel tank level, the other style the ohms decreases with a fill up. You will neeed to find out which your sender is by manually moving the float while measuring the ohms, then find out what type of sender your gauge is for.

Ammeter.... run a 10 gauge wire from the hot lug of the starter solenoid (ford type) to the fusebox. This is the only power feed to the fusebox, put the ammeter inline on this wire. If your ammeter is running backwards, swap which terminal the wires are on at the ammeter, (the "in" and "out" terminals)

[dscott]

RZ, If you look at the back of the gauge it should tell what the ohms for the sending unit are. There are 2 GM styles, 0 to 90 ohms, and 33 to 230 ohms. Check with EM and see which sender they use. You may also need to provide a separate ground to the sending unit from the frame. Most of the time it is a mismatched sending unit.

Wire # 130 is gauge power on the dash harness. You can splice into that wire for the amp gauge.
Don

[petek]

Also... if the sender is disconnected from the gauge, the gauge will read full+ (usually goes all the way up and then some).

You might want to take a minute and measure the resistance at the end of the sender wire at the gauge with the wire disconnected from the gauge to make sure you have the correct wire.

[ronzara]

This is a Stewart Warner (From the Cobra Set) Fuel Gauge:

I have the 134 wire attached to the "S" on the back of the gauge And it runs to Sender lug on the tank. I have the 130 wire attached to the "I" on the back of the gauge, and the 190 to the "G".
Gauges Pegs on the FULL side.
If I reverse the the "S" and "I" wires, it pegs on the EMPTY side.

There is about 3-4 gallons of gas in the tank.

130 is showing 12v with key ON.
when I put the meter on the "I" lug (POS) and touch the "S" lug with the NEG I show 12v.

with the key on, at the tank, I touched the POS pole to the Sender lug, and the NEG to a ground, and get 0 reading.


Any Idea's or suggestions?



Also, What do I need to attach to make the Alternator Charge the Battery?
I have all the CR Engine wiring connected but have seen nothing for this. ???


I have connected my horns to the proper wires, but when I press the Horn button on the wheel, I can hear the relay clicking, but NO HORN. ???

[dscott]

Rz, It sounds like the gauge is hooked up properly. You won't get a voltage reading from the sender because you are changing the resistance of ground. I still think you have a mismatch of the gauge and sender.

The alternator circuit needs to have the idiot light in the dash harness hooked up. This completes the charging circuit. It won't show a charge unless you have the dash harness plugged in.

The horns need 2 wires to them # 154 and a ground to chassis. Make sure you have a fuse in the fuse box for the horn.

Don

[ronzara]

Don,
Shouldn't there be a wire running back to the Battery on the Positive side to charge it while the car is running??
I don't have this.

I have connected #130 to the Amp gauge on the + side. I attached a ground to the other lug, popped the 10amp fuse. I guess maybe the chassis of the gauge grounds on the dash itsself????

How do I go about testing the Sender in the tank to find out which one it is?

The gauge gives no indication on the back of it, either.
Thanks!!
RZ

[Snake]

Hi Ronzara. I'm running SW gauges...and I have to agree with DScott. You have the same problem I had......the gauge pind to Full...and the tank was empty....you got the wrong fuel tank sender. I had the right sender for my gauge so I just had to remove the tank....and then modify the sender....since yours is a EM...you might have no problem in just changing the sender for the right one....but for me the CR Cobra tank was alot more difficuilt to do, since it is attached to the whole mounting section for the return and emissions lines for the tank.

If you don't have any numbers on the gauge. Some of the SW gauges have it indicated in the face of the gauge at the bottom...just under the needle...or call who ever you bought it from and, ask them what the ohms are for that gauge....or ask them to send you the right sending unit for it. I'm sure DScott is right.....it's the sender unit.

Did you buy the gauges from SW....is this the gauge set? http://www.xks.com/SW%20Pages/swgaug13.html
If so, it says the SW-82303 Fuel Level, 240 OHMS or the
SW-82413 Fuel Level, 240 OHM. In any case there both 240 OHMS.
Snake.

[ronzara]

Hey Guys,
Thanks for your quick response. I guess you can relate to how anxious I am you get the car on the road.

SNAKE,
Yes that is the same Gauge package I have installed.
My Tank is what EM calls for,.. 67-69 Camaro Tank. I am assuming the sender is the stock one. It was installed in the tank when I bought it. Where would I find the proper Ohm sender that fits my tank???

[Snake]

Ronzara. I think you should get in contact with EM...and tell them your problem....They would be the best bet...and probably know where, and what to buy for your tank sender...I'm sure there is a few guys with SW gauges and had the same problem.

So you need a 240 OHMS sender...maybe DScott would know....he Knows alot about this stuff.... For me it's my first build..and I had the same problem you have...and Don told me it was probably the sender that was wrong for the gauge...and he was right. My Cobra is almost finished about 98% done...can't wait to go for a cruse...so I know exactly how you fell...!!!!!
Latter
Snake.

[dscott]

RZ, The amp gauge is an in-line. Positive on both sides to show current draw. It needs to be in-line with the other gauges. If you ground it the fuse will pop. A voltmeter will have a ground and a hot.

There is no way to check the ohms on the sender unless you can move the float so, it must be pulled. I would call whoever sold you the tank and the gauge to see if it's a match. If it is then you must have a wiring problem, pinched or broken? Or no ground to the frame.

On the solenoid the extra wires with the battery cable are the charging circuit, and power to the circuit breaker, # 109 is from the regulator. You don't need any other wires. Make sure the extra wires are not on the starter side.

Don

[ronzara]

Don,

Are you saying I should have a #130 wire attached to both sides of the Amp Gauge??

I have the Idiot light working properly now. But I only have a 130 wire attached to the + lug of the Amp Gauge, nothing else. The guage doesn't seem to be doing anything.



Also I have no head lights:

I am using a 3 position toggle:
The Bottom Lug has #112 attached,
The Middle Lug has #171 Attached
The Top Lug has #141 attached

I have #144 and #190 going to the Hi BEAM indicator light.

The Head lights I have wired LO BEAMs to #142
HI BEAMS to #144 and the Grounds to #190,

I have a plug with wires 141, 143, 145 connected to the floor-mounted dimmer switch.


What is the configuration for parking/ tail/ stop lights:
I am using 4 (L-692) lamps in the rear and 2 (L-692) in the front.
How many of these should be Double filament fixtures?


Thanks.

[Jack21]

Let me know how your fuel tank gauge issues get resolved.

Using 0-90ohm Autometer gauge, and CR tank sender which is supposed to be a 0 - 90 ohm also.

With 5 gallons, gauge reads 1/2. With 10 gallons, gauge reads full. Any more fuel and gauge pegs. Anywhere between 1/2 and full, needle swings wildly with any movement of the car.

Called CR for a replacement tank pickup and sender. They're on backorder.

Next option is to get a sending unit from Autometer, and another fuel gauge that matches the sending unit from Autometer. The 0 - 90 ohm won't work. So the dash has to come back off to swap the gauge if I go this route.

Next option is to have a 0 - 90 ohm sender made by a street rod gas tank company. I just need a model to use for measurements. If I can get my hands on one without using the one that's in the car now, I'll do it, and have prints for replacements. Otherwise, I'll wait until winter when I'm more inclined to take car off the street.
What I want to do is have all the parts I need to fix this before dropping the tank.

As irritating as this is, the car is drivable, and this is driving weather. Around the end of November, the weather will turn crummy, I'll take the car off the street, pull it apart and fix it.

[dscott]

RZ, Yes, 130 on both sides of the amp gauge but, the wires can't end at the gauge, they have to be in a circuit that's drawing power.

What type of switch are you using for the headlights? I use a 3 position 6 pole switch and wire it as follows.
As you look at the back of the switch from the bottom I label the poles as 1,2,3 on the left and 4,5,6 on the right. #112 goes to pole 2 and 5, #171 goes to 1 and 3, #141 to 6, 4 is not used.

You only need double filaments on the front lights and the red tail/stop lights. The amber are turn signal and 4 way flashers, they only need a single filament.

The dimmer switch has the proper wires. # 141 is power and the other 2 are hi-lo beam.

Don

[ronzara]

Don and Snake,
You're right (as usual) my gauge and sender ARE mismatched. I am trying to swap gauges. I found the same gauge with 90 Ohm guts. Available through XKS.com ($32) >>> Cheaper than a new sending unit and should take care of my problem. thanks.


OK, on the AMP gauge...... If I run #130 to one side of the Amp Gauge and then come OUT of the gauge with a Hot wire to ..... say,.... the Fuel gauge, then this would make the Amp Gauge work????

HeadLights.... The switch I am using on the head lights is a standard Plastic toggle I got in my set of dash parts. It has 3 prongs on the back with tapped holes and screws to hold the wires on it. I am guessing this is about a 20 Amp switch. Is there one you recommend that is better suited for the Head Lights??
Do you think this is why the lights are not working?


RZ

[dscott]

RZ, Yes the amp gauge will work that way.

You need to find out what type of switch you have. Usually a 3 pole switch is on,off,on. If that is the way your switch is then it won't work properly. If it's an off,on,on then it will work. Check it and let me know. You also need to check the dimmer and make sure the wires are going to the proper location.
Don

[ronzara]

Don,
I am sure the switch is the problem. I touched the 112 wire to the Headlights wire and they came on, and the dimmer worked properly, too.

Is there such a thing as a 3 throw toggle OFF ON ON ??? I have looked at every parts store in Myrtle beach with no luck. They say there is no such thing....

If you know where to get them, please let me know. I don't really like the looks of standard pull out type switch, but of course they a readily available. And if I have to go that route.... I guess I will.
Thanks
RZ

[dscott]

RZ, If you can't find one call Finishline, they carry the entire line of Lucas switches including the headlight switch. Classic Roadsters can also sell you the 6 pole switch. The best bet would be Finishline for a matched set. I get all my switches from Classic Roadsters.
Don

[Jack21]

If there is an old British Sports car parts store in Myrtle Beach, they would carry your switch. If Finishline has it in stock, you can have it the next day. Service wise, they're pretty good.

I get most of my British OEM stuff from europaspares.com in UK. Better prices, and shipping is about 3 days. Gas cap, side mirrors, bumpers, emblems, wheel spinners, windshield & frame, luggage rack, all came from europa.

Actually, the 3 most used catalogs building a Cobra was Ford Motorsport, Summit, and Europaspares.

I converted dash from British toggle switch to American street rod, and still have the toggle switches in a box somewhere. I'll go look if you're interested.

[ronzara]

Jack,
That would be awesome. I would appreciate any help. Thanks
RZ