Gas Guage Again

super99 · May 10, 2021

I had time today, so I worked on the gas guage again on the Oliver 1550. I picked up a couple more used guages that worked when replaced and a new sending unit just in case. I tried the guages with no luck, then I changed the sending unit. I made a new wire from guage to sending unit. Now when you turn the key on, the needle goes to full and stays there(tank is about 3/4 full). With a test light, I have a light on the power in side of all of the guages and nothing on the side going to the guage, I took the guages to the wire wheel and shined up where the spring on the mounting bracket touches the outside of the guage, still not reading what is in the tank, The new sending unit had directions on how to set it up for the depth of the tank, so I measured and followed the directions and it still don't work. What the H-LL am I missing here?????

T.R.K. · May 10, 2021

Do you have a good ground to the tank? (Actually to the sender.)

mtf · May 10, 2021

Do the gauges you have match the same ohm range as the sending unit you have? Nathan

super99 · May 10, 2021

The sending unit has a ground wire spade on it hooked to a good ground. The sending unit is from Agco and the guages are Oliver original equipment. Where would you find out what the ohms are supposed to be???

Steve@Advance · May 10, 2021

I really don't know what to add, other than to get the gauge working before putting the sending unit in the tank.

Be sure the vertical travel of the float is equal to the depth of the tank. Sometimes you have to adjust the length of the float arm.

Michael Soldan · May 10, 2021

I'm thinking that the gas tank is not grounded to the tractor , could this be the problem ?

used red MN · May 11, 2021

Do you have another one of those ..oily all overs.. with a working gauge from that series around? Use a test light with an incandescent bulb, unhook the wire from the tank and connect your test light in series to a ground. See what level the dash gauge reads, do the same on the tractor with the working gauge. If they both read the same with the test light connected it is likely a problem with the new sender. A variation between what the two gauges read could mean a problem in the dash end.

super99 · May 11, 2021

The new sending unit came with instructions for installing. Measure the depth of the tank and then the chart tells the length of the float arm and where to fasten the sending unit which I did. The guage works on the 1850, I hate to do all of the extra work, but I suppose I could take the working guage out of the 1850 and put it in the 1550 and see if it works and try the guage from the 1550 in the 1850. I'm about ready to cut a stick the right length and carry it with me!!!

MarkB_MI · May 11, 2021

Are you sure the new sending unit is compatible with the old gauges?

super99 · May 11, 2021

How are you supposed to know that, is it marked somewhere on the package? When you go to the dealer and ask for parts and tell him what you are working on, The parts pages on the computer are supposed to tell him the right part to give you.

Blackhole49 · May 11, 2021

No help to you, but I must have really gotten lucky. This tractor has dual tanks that read separately on one gauge with a switch. The gauge was missing when I bought it last year, so I just ordered a cheap gauge off Amazon not knowing if the sending units were any good. Both tanks read correctly.

John T · May 11, 2021

If turning the power on to the gauges input causes full needle deflection and that's so regardless of tank level, that makes me believe the sending unit IS THE WRONG RESISTANCE, it doesn't match the gauge. The sending units resistance must be matched for the gauge BUT I CANT TELL YOU the proper sending unit to match your gauge.

ALSO if the wire and circuit from gauge output to sender were shorted out somewhere that might cause full deflection, insure there are no shorts in the gauge itself or the wire from it to sender. However if the gauge had its own internal faulty short to ground, it would deflect even if no sender was attached. Id say its more likely a sender versus a shorted gauge problem.

Full needle deflection makes me believe you have adequate voltage on the gauges input plus there's a good ground (circuit from gauges output to and through sender to ground). IE its if there were NO deflection Id suspect a bad/missing ground connection, but full deflection makes me think the ground is okay.

If you remove the sending unit but have everything wired up correct including a good ground return for the sender and turn power on holding the sender mount horizontal, the gauge (if sender is right resistance) should swing from full to empty IF ITS THE RIGHT RESISTANCE

If worse comes to worse one possible solution is to buy a whole new gauge with sensor package.

Best I have to offer not being there

Best wishes and good luck

John T

bc · May 11, 2021

Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

jimg.allentown · May 11, 2021

What you need is an ohm meter and a box of assorted resistors.

First thing is to find out if the gauge actually works. Start by choosing a resistor that will cause the gauge to read full. Follow that with another one to give an empty reading. If you can get these readings, that should prove that the gauge is working.

Next, check your sender's resistance at the bottom and top of the tank.Compare with the resistances needed to give empty and full readings. If they are compatible, everything should work - if the wire connections and grounds are not compromised.

This is the approach I would take long before getting out the parts cannon.

JMOR · May 11, 2021

(quoted from post at 08:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

ll I can say is 'WOW!"

JMOR · May 11, 2021

(quoted from post at 20:43:34 05/10/21) I had time today, so I worked on the gas guage again on the Oliver 1550. I picked up a couple more used guages that worked when replaced and a new sending unit just in case. I tried the guages with no luck, then I changed the sending unit. I made a new wire from guage to sending unit. Now when you turn the key on, the needle goes to full and stays there(tank is about 3/4 full). With a test light, I have a light on the power in side of all of the guages and nothing on the side going to the guage, I took the guages to the wire wheel and shined up where the spring on the mounting bracket touches the outside of the guage, still not reading what is in the tank, The new sending unit had directions on how to set it up for the depth of the tank, so I measured and followed the directions and it still don't work. What the H-LL am I missing here?????

do not know Oliver, but as some have said, the gauge and sending unit must match. Some systems, full=zero Ohms and Empty may be 30, 60, 200 Ohms. Then others are just the opposite, with Empty=Zero Ohms and Full=30, 60, 200 Ohms. Both the empty & full directions as well as specific Ohms at full or empty extremes must match. Measure your sender's Ohms at both Full and Empty and connect gauge to power and ground the other terminal & tell me if it reads Full or Empty when powered & grounded and what it reads with no connections powered.

Ozlander · May 11, 2021

(quoted from post at 07:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

Nope, a heavy bus bar has little resistance.
A 30 gauge wire has a lot of resistance.

bc · May 11, 2021

(quoted from post at 09:32:34 05/11/21)

(quoted from post at 08:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

Click to expand...

ll I can say is 'WOW!"

JMOR. Now you have me wondering since I was just guessing at a possible solution. Was that a WOW for being a good idea or a WOW for being a stupid idea? Don't worry, you can't hurt my feelings as my backside has been paved over a few times in my life. lol Probably sitting at 50/50 on the good/bad ideas. I couldn't tell you if there is much of a resistance change between something like 8 or 10 gauge compared to 14, 16, or 18 gauge. Doesn't sound like we are dealing with a great amount of ohm resistance though.

JMOR · May 11, 2021

(quoted from post at 15:41:57 05/11/21)

(quoted from post at 09:32:34 05/11/21)

(quoted from post at 08:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

Click to expand...

ll I can say is 'WOW!"

Click to expand...

JMOR. Now you have me wondering since I was just guessing at a possible solution. Was that a WOW for being a good idea or a WOW for being a stupid idea? Don't worry, you can't hurt my feelings as my backside has been paved over a few times in my life. lol Probably sitting at 50/50 on the good/bad ideas. I couldn't tell you if there is much of a resistance change between something like 8 or 10 gauge compared to 14, 16, or 18 gauge. Doesn't sound like we are dealing with a great amount of ohm resistance though.

was trying to not be too harsh. It was, " Maybe try some heavier gauge wire as the heavier the wire the more resistance it has." that elicited the response. Actually, the heavier the wire (smaller gauge numbers), the LESS the resistance. Here he is dealing with 30, 60, 200 Ohm range and even a small (higher gauge number) 16Ga wire only has 4 Ohms resistance per 1,000 feet. Your 0Ga battery cable is just under 1/10 th Ohm per 1,000 ft.

gab · May 11, 2021

Here's the ohms on a brand new 97 Grandprix sending unit. 1.5 equals empty, 4.6 = 1/2 tank and 93.4 is full. We had a tool at work to check gauge operation which was two cables on a box with a knob and display, 1 equaled empty, 44 was a half tank and 88 was full, however that didn't necessarily hold true for all cars and sure as hell didn't apply to Olivers.

gab · May 11, 2021

correction 46 is half, not 4.6

JMOR · May 12, 2021

(quoted from post at 19:13:21 05/11/21) Here's the ohms on a brand new 97 Grandprix sending unit. 1.5 equals empty, 4.6 = 1/2 tank and 93.4 is full. We had a tool at work to check gauge operation which was two cables on a box with a knob and display, 1 equaled empty, 44 was a half tank and 88 was full, however that didn't necessarily hold true for all cars and sure as hell didn't apply to Olivers.
<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto88047.jpg>

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto88048.jpg>

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto88049.jpg>

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto88050.jpg>

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto88051.jpg>

ust backing up my point of 'there is no "standard", each went their own way'. So, you need a gauge & sender that match.

bc · May 12, 2021

(quoted from post at 15:07:53 05/11/21)

(quoted from post at 15:41:57 05/11/21)

(quoted from post at 09:32:34 05/11/21)

(quoted from post at 08:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

Click to expand...

ll I can say is 'WOW!"

Click to expand...

JMOR. Now you have me wondering since I was just guessing at a possible solution. Was that a WOW for being a good idea or a WOW for being a stupid idea? Don't worry, you can't hurt my feelings as my backside has been paved over a few times in my life. lol Probably sitting at 50/50 on the good/bad ideas. I couldn't tell you if there is much of a resistance change between something like 8 or 10 gauge compared to 14, 16, or 18 gauge. Doesn't sound like we are dealing with a great amount of ohm resistance though.

Click to expand...

was trying to not be too harsh. It was, " Maybe try some heavier gauge wire as the heavier the wire the more resistance it has." that elicited the response. Actually, the heavier the wire (smaller gauge numbers), the LESS the resistance. Here he is dealing with 30, 60, 200 Ohm range and even a small (higher gauge number) 16Ga wire only has 4 Ohms resistance per 1,000 feet. Your 0Ga battery cable is just under 1/10 th Ohm per 1,000 ft.

OK. I'll settle for half stupid then. I think the fuel sender basically serves as a variable resistor in the circuit though.

JMOR · May 12, 2021

(quoted from post at 19:18:38 05/12/21)

(quoted from post at 15:07:53 05/11/21)

(quoted from post at 15:41:57 05/11/21)

(quoted from post at 09:32:34 05/11/21)

(quoted from post at 08:33:30 05/11/21)
Sounds to me like you might need a resistor or something similar to reduce the ohms coming from the sender. Maybe try some heavier gauge wire as the heavier the wire the more resistance it has. Also the longer the wire the more resistance it has. Start with a long piece of heavier wire and cut it down till you get the gauge reading 3/4.

Click to expand...

ll I can say is 'WOW!"

Click to expand...

JMOR. Now you have me wondering since I was just guessing at a possible solution. Was that a WOW for being a good idea or a WOW for being a stupid idea? Don't worry, you can't hurt my feelings as my backside has been paved over a few times in my life. lol Probably sitting at 50/50 on the good/bad ideas. I couldn't tell you if there is much of a resistance change between something like 8 or 10 gauge compared to 14, 16, or 18 gauge. Doesn't sound like we are dealing with a great amount of ohm resistance though.

Click to expand...

was trying to not be too harsh. It was, " Maybe try some heavier gauge wire as the heavier the wire the more resistance it has." that elicited the response. Actually, the heavier the wire (smaller gauge numbers), the LESS the resistance. Here he is dealing with 30, 60, 200 Ohm range and even a small (higher gauge number) 16Ga wire only has 4 Ohms resistance per 1,000 feet. Your 0Ga battery cable is just under 1/10 th Ohm per 1,000 ft.

Click to expand...

OK. I'll settle for half stupid then. I think the fuel sender basically serves as a variable resistor in the circuit though.

a got that right! I don't call "stupid" on almost anyone........we can all learn something. Politicians are an exception though! :evil:

Gas Guage Again

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Similar threads