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Cwcb08
10-12-2016, 10:17 AM
my engine temp is not working

i took off the plug and grounded it and the guage goes all the way to hot, remove the ground the guage goes back, ok should be simple replace the sender. picked up a new one from car quest and installed ( no teflon just what was already on the threads ) replaced the bullet connector ( new sender has a smaller post ) fire up the car let run for 15 min, no reading, check the rad hose temp 165f, unplug the connector ground it guage moves.

im stumpped, guage works, wiring obviously works, and sender is new, any suggestions

YellowRose
10-12-2016, 11:06 AM
Cody, is your gas gauge and other gauges working? Often, this can be a problem with the Constant Voltage Regulator (CVR) unit that takes the 12v from the system, and down grades it to 6v for the 6v gauges. This causes problems to the gauges, IF that 12V is getting to the gauges instead of 6v. But lets see what jopizz has to say when he sees this. I fixed your pix for you.

Cwcb08
10-12-2016, 11:11 AM
the oil temp works, and im not sure about the ammeter, it sits in the middle even when the battery is disconnected, is that normal? the engine temp doesn't and the fuel guage didn't, i forgot to look at it again after i fixed the low fuel light relay

YellowRose
10-12-2016, 11:28 AM
As I recall, with the battery disconnected, or the key turned off, the gauges should go to the far left side and rest. At least that is the way it is on my Squarebird. Hopefully, jopizz or someone with better knowledge than me, will be on here shortly, and be able to help you. It could be anything, like a previous owner getting in there and wiring the gauges incorrectly.. Or a possible problem with that CVR unit. IF it is that, you may have to replace it. If you do, I would replace it with one of the new solid state ones. Our webmaster, Dave Dare ~ simplyconnected, can take your OEM CVR and convert it to a solid state one, and send it back to you. He can give you the details on that IF that is the problem..

YellowRose
10-12-2016, 02:33 PM
BTW, Cody, all the wiring schematics for your Tbird are in the Technical Resource Library (TRL). You can click on them to expand them, or print them out as needed. If you do not have them, there they are for you. The link to it is always part of my signature element and also John's ~ jopizz.

jopizz
10-12-2016, 04:53 PM
If the gauge goes all the way to Hot when you ground the wire your CVR is probably good. If you have a test light put it on the wire. You should see it pulsing and not solid. Did you ground the wire to the engine block or battery? If the sender is good and your engine is properly grounded it should work. If not it can only be one or the other.

John

Cwcb08
10-12-2016, 05:07 PM
If the gauge goes all the way to Hot when you ground the wire your CVR is probably good. If you have a test light put it on the wire. You should see it pulsing and not solid. Did you ground the wire to the engine block or battery? If the sender is good and your engine is properly grounded it should work. If not it can only be one or the other.

John

i grounded it to the battery, i will test against the block 2moro as im about to leave for work

Yadkin
10-13-2016, 02:18 PM
Fuel, oil and temp all work the same way. Each gauge is a little 6V heater that makes a bi-metal coil change length and at on the indicator needle.

The ammeter is different. For '64 it is an actual shunt, where full alternator amperage runs through it then over to the power panel on the passenger side kick panel. The needle should be in the middle with key off, to the left with key on accessories and stuff running, to the right with engine running. Later years (Dave Dare can verify) might use a remote shunt. These are a fire hazard if you install a higher amp alternator and power accessories, so plan accordingly.

For the temperature gauge, test the sender mounted on the intake, disconnect the wire. Use an ohmmeter between the brass hex and the electrical connection. It should read 100 ohms cold, 10 ohms when 180F. Then check ohms between the connector and the intake, then the block, then the chassis. If you don't have proper grounding the gauge won't work.

Cwcb08
10-16-2016, 10:00 AM
If you don't have proper grounding the gauge won't work.

looking under the hood last night, where should the battery ground to the block? mine grounds to the AC idler pulley bracket?

simplyconnected
10-17-2016, 05:22 AM
Where did Ford put it, or where does it belong?
Ford saved money by putting the shortest copper wire at the closest attachment point.

Your starter motor draws the most current so a good, healthy copper wire needs to stretch to that area. I run a #4AWG from the battery post to a bell housing bolt next to the starter motor. I also 'hang' both (starter motor and ground) wires from a clamp along the engine so vibration doesn't destroy the lug on the starter motor.

Notice that modern cars have a smaller (green #10) body ground wire, connected close to the battery. That's important to prevent body current from returning through drivetrain bearings. Ford cars used a braided wire that stretched from the back of the head to the firewall. - Dave

Cwcb08
10-17-2016, 12:22 PM
Where did Ford put it, or where does it belong?


Yes where did ford put it on a AC car, mine is currently grounded to the adjustment bolt of the AC tensioner pulley bracket


Last night I Pulled off the wire to the sender to ground it to the block vs the battery and the gauge didn't move( when grounded to the block or battery ) electrical can be frustrating

simplyconnected
10-17-2016, 01:06 PM
First, turn the key switch to the 'on' position. Then use your meter or a test light with one prod on neg. The other prod should be on the temp sensor wire and it should pulse 12 volts.

I prefer my homemade test light. It's simply a dash light soldered to two wires and taped. I have alligator clips on the ends of the long wires. I can see the light without looking at it and an incandescent lamp is a self-regulating load. If you don't have a spare dash bulb, use one of those holiday twinkle lights that cost three bucks per set. Cut off four or five bulbs in a series and lengthen the wires. Six bulbs in series will produce a slightly dimmer light but will last forever.

On a cold engine it doesn't matter whether the wire is on the block sending unit or not because the sending unit lowers resistance when the engine is hot (sending the gauge needle towards 'H').

Your fuel gauge works the exact same way; an empty tank has a high resistance to ground. A full tank sends the gauge needle to 'F'. Power removed (key off) should send the gauges to or below 'cold' or 'empty'. - Dave

Cwcb08
10-17-2016, 01:25 PM
( it won't let me post when i answered within a quote ) First, turn the key switch to the 'on' position. Then use your meter or a test light with one prod on neg. The other prod should be on the temp sensor wire and it should pulse 12 volts.

I prefer my homemade test light. It's simply a dash light soldered to two wires and taped.

ok i will make up one of those lights

On a cold engine it doesn't matter whether the wire is on the block sending unit or not because the sending unit lowers resistance when the engine is hot (sending the gauge needle towards 'H').

like i posted, i tried this on a cold engine and it didn't move when i grounded it but i dont know why, it worked last test?

Your fuel gauge works the exact same way; an empty tank has a high resistance to ground. A full tank sends the gauge needle to 'F'. Power removed (key off) should send the gauges to or below 'cold' or 'empty'. - Dave

when testing the low fuel light the one wire i grounded made the light come on, if i ground the other the guage should go to full? i tried my multi meter on the sender and the number kept jumping up and down i guess it was the tank sloshing as i had backed her up onto ramps a few minuets prior( does that sound like a bad sender?)

simplyconnected
10-17-2016, 04:14 PM
You can do all your electrical tests just using the wires connected to (both) the sending units.

Disregard the Low Fuel Relay. You need to look at power that starts at the CVR (constant voltage regulator). The CVR feeds both fuel and temp gauges with the same power, which is pulsating 12-vdc. In fact, the gauges are identical, too.

You are looking for the gauges to deflect to full scale, here. Each gauge feeds respective sending units that both run between 10-100 ohms. Ten is 'hot' or 'full' and 100 is 'cold' or 'empty'.

Grounding either wire at the sending unit should send the gauge to full scale. Limit this time to one minute (or use a 10-ohm resistor in series). If you don't see power at the sending unit move to the gauge. If you don't see power at the gauge, you need a new CVR. It's that simple.

These gauges and sending units are made by King-Seeley for Ford. They use current through a ni-chrome wire wrapped around a bi-metal strip to move the needle. That means the polarity on the gauges makes no difference. There is no motor or armature, only a bi-metal strip that bends with heat. That's why we rarely see 'bad gauges'. CVRs go bad all the time. When new, they have a on-off duty cycle of 50%. As they age they get erratic, they open or they short inside.

BTW, I convert CVRs to solid state. - Dave

Yadkin
10-18-2016, 09:42 AM
looking under the hood last night, where should the battery ground to the block? mine grounds to the AC idler pulley bracket?

This is the most important ground on the car- it shouldn't be on a bracket, but directly to the block. Mine's on the passenger side in front. The bolt is fairly large, screws in horizontally into the side of the block. See the copper in the picture? That's the connector.

Don't get confused by my custom serpentine belt assembly or headers.

Yadkin
10-18-2016, 09:57 AM
Here's another picture showing the #4 gauge wire from the battery negative to the chassis then onto the block. The yellow is a flashlight to illuminate the block bolt (painted black). The chassis ground bolt is silver colored (zinc) and is screwed vertically down into the heavy chassis member the carries the front bumper.

The factory did this cable with one continuous cable from the battery to the block, and a tee type connector at the chassis. I replicated it using hardware store #4 copper connectors, cutting, bending, soldering, drilling and insulating.

simplyconnected
10-18-2016, 02:59 PM
NEVER use lead or solder on a wire that carries hundreds of amps. The proper connection is always done using either a crimp or a mechanical screw clamp. This applies to all wiring as covered by the National Electrical Code. Notice that all car manufacturers conform to this standard as well.

The reason has little to do with lead toxicity but more to do with lead's resistance. Resistive loads heat and because lead melts at low temperature, a high-current lead splice or connection can fall apart.

Engines vibrate. It's a fact of life. Ford did not support their wires very well but that doesn't make the installation correct. It just means, it works. Never let a connector bear flexing because eventually it will fail (I've seen it many times, as an Electrician). One sign of a good job can be judged by how well everything is supported. I've seen brake lines hanging out and shaking in the breeze with no support and it makes me cringe, so 'plumbing' (yes, even in your house) needs proper support as well.

A properly done job separates the professionals from the hacks. Just because something works doesn't mean it's right. Just yesterday, we were discussing the practice of putting a penny behind a blown plug fuse as a 'temporary fix' during the night. Yes, it works but now the wires in the walls ARE the fuse. - Dave

Yadkin
10-18-2016, 11:09 PM
That's the first I've heard that Dave. I use an electrical solder that is 99.2% tin, 0.5% copper, 0.3% silver, and measure no resistance in a foot of it.

Cwcb08
10-19-2016, 02:14 AM
The factory did this cable with one continuous cable from the battery to the block, and a tee type connector at the chassis.



ok thanks, i moved my ground to that bolt from the bracket, it must be a new cable as there is no sign of a T to ground to the frame

simplyconnected
10-19-2016, 08:47 AM
That's the first I've heard that Dave. I use an electrical solder that is 99.2% tin, 0.5% copper, 0.3% silver, and measure no resistance in a foot of it.Steve, you cannot measure the resistance until current goes through. I'm going to keep this simple... Copper has a resistance of .000000017 (1.7x10-8th) ohms per meter. Can your meter measure that? Why do copper wires get hot? If the answer is because of the wire's resistance, why would you separate the copper conductors in a connector or splice with metal (lead and tin) that has ten times more resistance than copper? (.00000019 ohms/M or 1.9x10-7th) Again, this resistance is so low, your meter cannot measure it. Now, add hundreds of amps and watch the voltage drop.

Why do you think your battery measures 12-volts, but while cranking it commonly goes down below 8-volts? We 'say' the battery has internal resistance but it never shows under light load. All resistance works that way.

Connect a common resistor to one battery terminal and measure voltage between it and the other battery post with a digital volt meter. A 10-ohm resistor should drop voltage and so should a 1k resistor but your meter will show 12VDC on either resistor because no current is going through it. The same holds true with your splices. Their resistance is more conveniently measured under load as a voltage drop (I squared R).

An unbroken wire has the lowest resistance. Problems always happen at connections, not in the middle of the wire. For this reason, the code only allows terminations in a box. There is no better connection than mashing copper wires into each other so they become one metal, such as a crimped connection. Adding ANY metal that separates the copper only increases resistance. - Dave

Yadkin
10-19-2016, 10:35 AM
ok thanks, i moved my ground to that bolt from the bracket, it must be a new cable as there is no sign of a T to ground to the frameThat's the main chassis ground so it's very important. If you don't want to make a cable to replicate the original as I did then use two cables- one from the battery to the engine block and a second short one from the block to the chassis.

Yadkin
10-19-2016, 10:36 AM
Steve, you cannot measure the resistance until current goes through. I'm going to keep this simple... Copper has a resistance of .000000017 (1.7x10-8th) ohms per meter. Can your meter measure that? Why do copper wires get hot? If the answer is because of the wire's resistance, why would you separate the copper conductors in a connector or splice with metal (lead and tin) that has ten times more resistance than copper? (.00000019 ohms/M or 1.9x10-7th) Again, this resistance is so low, your meter cannot measure it. Now, add hundreds of amps and watch the voltage drop.

Why do you think your battery measures 12-volts, but while cranking it commonly goes down below 8-volts? We 'say' the battery has internal resistance but it never shows under light load. All resistance works that way.

Connect a common resistor to one battery terminal and measure voltage between it and the other battery post with a digital volt meter. A 10-ohm resistor should drop voltage and so should a 1k resistor but your meter will show 12VDC on either resistor because no current is going through it. The same holds true with your splices. Their resistance is more conveniently measured under load as a voltage drop (I squared R).

An unbroken wire has the lowest resistance. Problems always happen at connections, not in the middle of the wire. For this reason, the code only allows terminations in a box. There is no better connection than mashing copper wires into each other so they become one metal, such as a crimped connection. Adding ANY metal that separates the copper only increases resistance. - Dave
I mash then solder on these big connections.

scumdog
10-19-2016, 03:46 PM
I mash then solder on these big connections.

Likewise.

All my soldering is done thus: crimp the fitting, coat it in plumbers flux (very caustic!) then solder - THEN dunk in a baking-soda/water mix to neutralise the flux.

Shake the joint free of excess 'water' and let it dry completely before putting any shrink-sleeve stuff on.

Not the usual way to do things but I've had zero joint failure (Yet!?) in about 42 years. (Well that's how long I've had my F100 and I soldered joints in this manner on it)

simplyconnected
10-19-2016, 10:03 PM
Put a few stranded copper wires into a lug and crimp HARD. Now, cut the center open. It will look and act just like solid copper! There is NO room for solder or flux. Adding heat for soldering only compromises the metals, making them expand and contract. So stop soldering.

Just because it works doesn't make it right, as I discussed. NO power lines are ever soldered, and certainly not in a car. Soldering only gives a false sense of accomplishment.

Wire nuts are another very useful connection that most people have a hard time with. The first wire nuts were simply a conical spring with a 'tab'. As they were twisted over wires, the spring would 'dig into' the copper and crowd them together as it tightened. Modern wire nuts work the same way but now they have a plastic cap.

The test is when pulling HARD on the wires after tightening the wire nut. If a wire comes out, do it over. If a wire comes out again, do it over. All wires in a splice should be in there 'solid'. No copper should protrude past the plastic. I laugh when I see electrical tape around a wire nut. Usually, it means the wires are loose, and somehow the tape is supposed to make the splice tight but it never does.

I went through Ford's Electrical Apprenticeship (which is government sanctioned by the US Dept. of Labor), and I have vast experience in industrial controls. So, please take my advice. - Dave

simplyconnected
12-01-2016, 04:37 PM
All your gauge sensors can be checked with an ohm meter. The resistance is 10-100 ohms on all sending units.

A full tank will register 10 ohms.
A hot engine will register 10 ohms.
Half way on each is 50 ohms.

Think about this... That means you can swap leads from your gauges. If you have one that is 'known good' and another gauge doesn't work at all, swap the leads from the temp to the fuel gauge and see if both gauges are good. If so, continue to the sending unit that isn't working. - Dave