help: fuel gauge shows full when tank is half full

[bj40green]

Hi njzuk,

60's and early 70's have a different cluster. I'm not familiar with these but I will try to look it up for you.
What is exactly the problem?

Rudi

 

[Folkert]

haha dr rudy, your next patient is waiting....

 

[bj40green]

haha dr rudy, your next patient is waiting....

Yes, I noticed.

Sorry about the high jack but i have an older style guage cluster (65 to be exact) where can I get one of these Voltage Regulators. I'm 90% sure that is my problem. Since that part is non existant on my rig. thank you for any and all help in advance.
Keith

As far as I can figure it out, there is no voltage regulator in your cluster. It's straight forward. You have 4 individual meters. The plus 12V goes from key contact to Fuel, Temp and Oil gauges. From each gauge to sender. End of story. Very basic.

i think you can get any kind of resistor at stores like radio shack, as long as the ohm rate is the same you should be fine.

Yes, you're right but watch the size. I think it's a 5 or 7Watt (but can be a 10W) resistor. Bigger is no problem.

Good luck to all of you,

Rudi

 

[njzuk]

Same problem as Folkert. When it s full its pegged and when its empty its some where near the half way mark. all the stock wiring has been gutted. So the if the voltage regulator was any where other that the cluster its self its long gone. I have had the cluster appart several times and did not see any thing that looked like a regualtor.
Thanks again
keith

 

[njzuk]

Thank you! Ill give that a shot.
You guys are awesome!

 

[bj40green]

Thank you! Ill give that a shot.
You guys are awesome!

Hi Keith,

Just a shot in the dark..... There are 4 different sending units.
'58-'65, '66-'72, '72-'78 and '78-'84.
Maybe the PO replaced the sending unit but for the wrong year?
I can't find the specs for each unit. Maybe somebody else can chip in?

Rudi

 

[edwjmcgrath]

That resistor would have to be both 30 ohms and a pretty high power rating-probably not available at your local rat shak. It's carrying all of the current going to all of the meters. I think you'd be better off finding an OEM dropping resistor.

 

[bj40green]

That resistor would have to be both 30 ohms and a pretty high power rating-probably not available at your local rat shak. It's carrying all of the current going to all of the meters. I think you'd be better off finding an OEM dropping resistor.

There is only one dropping resistor in this cluster.
The resistor feeds only the Fuel gauge and not all of the meters.
The Fuel gauge feeds the Temp gauge with 7Volt.
The Oil gauge gets a direct 24 Volt.
The Amp gauge is stand alone.

Rudi

 

[edwjmcgrath]

There is only one dropping resistor in this cluster.
The resistor feeds only the Fuel gauge and not all of the meters.
The Fuel gauge feeds the Temp gauge with 7Volt.
The Oil gauge gets a direct 24 Volt.
The Amp gauge is stand alone.

Rudi

By "all" I meant all of the ones in the diagram. That is the fuel gauge, the fuel sender gauge, the temp gauge, and the temp sender gauge.

The current to all of those gauges goes through that one dropping resistor.
Your average 1/2 watt or 1 watt resistor from Radio Shack will smoke as soon as you turn the key.

 

[bj40green]

That resistor would have to be both 30 ohms and a pretty high power rating-probably not available at your local rat shak. It's carrying all of the current going to all of the meters. I think you'd be better off finding an OEM dropping resistor.

What do you mean by BOTH? There is only 1 (one).

By "all" I meant all of the ones in the diagram. That is the fuel gauge, the fuel sender gauge, the temp gauge, and the temp sender gauge.

The current to all of those gauges goes through that one dropping resistor.
Your average 1/2 watt or 1 watt resistor from Radio Shack will smoke as soon as you turn the key.

Look Ed or whatever your name is, English is not my first language but how can you use 4 times the word "gauge" in a 2 circuit system? As I understand it, a gauge is an other word for meter. I checked the dictioinary.

Where do you read about a ½ or 1 Watt resistor?
I wrote 5 or 7 Watt, maybe 10 Watt.

Are we on the same page here?

Rudi

 

[edwjmcgrath]

No...

 

[bj40green]

hi rudy, yes its the resistor, indeed was 30 ohm printed on it, but gave something like 120 ohm... when i hooked up the gauge directly ( bypassing the resistor) to 12v it works fine..

i'm happy i solved another thing on my to do list.

will install the reconditioned fuel tank in 2 weeks... hope this will go smoothly and not too much hassle with bleeding air etc. then its time to hit the road!!!

Folkert,

The code on the resistor is 20 H 30Ω J.
20 is the temperature in Centigrade, H stands for 12Watt, 30Ω and J stands for model.
In case you can't find the 30Ω OEM resistor here is a possibilty. click this link: Display Electronics - Multiple brand MB.512233E - Draadgewonden weerstand 33E 11,0W 10%
This company sells power resistors 11W but the range goes 22, 33, 47 so 33 is your best choice.

Good luck,

Rudi

 

[njzuk]

I think ill try a Ballast Resistor off of a old points style ingition that should drop the voltage down to where i needs it to be between 9- 6 volts. I will chime back in and let you guys know how it works out. Thank you again for all the help everyone.

 

[Folkert]

rudi, the resistor is a part you can order separate from Toyota...
on toyodiy.com, it even has a price tag, so maybe these are still available.. didn't ask the toyota dealer yet... no high priority anymore, since i got it just fine with my bypass, but just in case someone wants to have it:

24v > 12v 30 Ohm voltage dropper
Toyota part number : 83145‑60010