Fuel Tank/Sending Unit for March 1971 FJ40 (1 Viewer)

[softdrinkviking]

I am trying to get my sending unit to function properly and I ran into trouble.

My original gas tank was leaking way back in the 1990's and, through a series of long-winded events, my dad took the lead on a replacement and came up with what I think is a later model year tank.

From what I can tell, my tank was supposed to be 18 gallons, and the tank I now have is 16 and some change.

The hook-ups are identical to my old tank (curved filler neck, small filler vent port), so it fits in, but it is a little smaller.

Is it possible that Toyota makes the replacements with a smaller capacity now?

I found that a few of the parts vendors (SOR, Cruiserparts, Mark's) sell a separate tank for early - 9/71, so if I buy one of those, can I be sure I am getting a 18 gallon tank?

Can anybody tell me with certainty what is what with the fuel tanks?

If I can't get a bigger tank, does it work to bend the fuel sending unit?

Best,

Brian

 

[DSRTRDR]

I guess I am not understanding the problem you seem to believe you are having - what exactly is wrong with the current tank ?

the senders never were all that exact to begin with, so why not just go to the gas station at 1/4 when you keep good records for a while, you will get the hang of what the tank capacity is

 

[softdrinkviking]

I guess I am not understanding the problem you seem to believe you are having - what exactly is wrong with the current tank ?

the senders never were all that exact to begin with, so why not just go to the gas station at 1/4 when you keep good records for a while, you will get the hang of what the tank capacity is

Thanks for the reply.
Sorry if my post was unclear.

I have been "keeping records" for almost 20 years on this gas tank, and I definitely "have the hang of it."

My problem is that I am getting low readings at full, and then after it goes below 1/2 tank, it kind of fluctuates around, but it can stay close to 1/4 tank even when it's totally empty.
That is with the current new OEM gas sending unit.
I have had three sending units in this tank, first the original one that was in the car (which straight-up died), then an aftermarket one and now this new one.
The aftermarket one read correctly when full, but got vague at around 1/2 tank and was useless from that point on.

The reason I mentioned the gas tank capacity is that the original tank was supposed to be 18 gallons, and my current replacement tank is 16 gallons.

Will the lower capacity effect the sending unit?
If so, can I get a new 18 gallon tank, or are all the new OEM tanks 16 gallon? (for a March 1971)

If the capacity is irrelevant, will bending the sending unit get me more accuracy?

 

[Tanker120]

77100 TANK ASSY, FUEL
77001-60013 FOR L/T.C.S.S. 1
77001-60050 FOR W/T.C.S.S. 1

ToyoDIY shows two types for that year, I do not know what the codes mean but the top one is available from Toyota, but the number changed to 77100-60012, the bottom one is no longer available (ToyotapartsZone.com says this tank fits 1969.08-1971.09
https://www.discounttoyotaparts.net/toyotaoemparts.html
Above sells them for $305.89 + shipping

Sending unit $61.33
GAGE ASSY, FUEL SENDER
83320-35020

These are the sources I use and have been pretty successful with, Toyotapartszone.com will let you know if the part is still available, 90% accurate for me so far, ToyDIY is a great place to get Part numbers and the other site is one of the cheapest places to get the parts- although my local Toyota matches their price, try your local Toyota dealer, its worth a shot...Hope this helps

 

[softdrinkviking]

Thanks for the great parts site, i have never bought from them before.
It's a great price for a tank, good place to buy one.

So that is helpful, but I still don't know if buying the tank would accomplish what I want.
I really just want to know when my gas is low by looking at the gauge in the dash.

 

[Downey]

Wrong dash gauge readings???

Here's the problem: Senders and dash gauges up to Sept 1972 work on 110 ohms empty, 3 ohms full, BUT with a built-in 7 volt drop. Senders and gauges from Sept 1972-newer work on 120 ohms empty, 17 ohms full, and a full 12 volts. You've got to use the correct sender for your dash gauge!!!!

 

[Bang Bang]

You need to match the ohms on both the meter and the sender. Stock gauge, stock sender or aftermarket with the matched ohms. If you search MUD, you will find the Full - Half - Emptyy ohm ratings.

Edit: apparently Jim beat me to it.

 

[Downey]

New Tank

BTW, here's some Gee Whiz information: Many, many buy the rear aux tank/fuel cell to be used as their one and only stand-alone tank. Minor reason, it's 22 gallon. Another minor reason, it gets fuel/fumes outside the passenger compartment. Major reason, anybody over about 6 ft. tall looks out the top of their windshield at about wiper blade level. They can't lower the seats because of the interior tank. No interior tank allows righteously mounted bucket seats.

 

[bj40green]

Cluster gauges and senders are a "set". You can't use a later sender with an earlier cluster, or a later cluster with an earlier sender.
Senders:
03/69-09/72 83320-35020
09/72-01/79 83320-60050
01/79-04/86 83320-60051

The first sender works on 12V and ranges between 6.5 and 2.1 ohm.
The second sender works on 7V and ranges between 120 and 17 ohm.
The third sender is electrically equal to the second but the float arm is longer due to a different tank depth.

More info here: -► on Clusters, Gauges and Odo meters post #9

Anyway, on your '71 the correct sender (for your cluster) is 83320-35020 as said before. If you use a different tank you'll have to bend the float arm to an acceptable reading that works for you.
You don't mind if the FULL indication is correct. You want to know when your tank is almost empty.

Rudi

 

[Downey]

Cluster gauges and senders are a "set". You can't use a later sender with an earlier cluster, or a later cluster with an earlier sender.
Senders:
03/69-09/72 83320-35020
09/72-01/79 83320-60050
01/79-04/86 83320-60051

The first sender works on 12V and ranges between 6.5 and 2.1 ohm.
The second sender works on 7V and ranges between 120 and 17 ohm.
The third sender is electrically equal to the second but the float arm is longer due to a different tank depth.

More info here: -► on Clusters, Gauges and Odo meters post #9

Anyway, on your '71 the correct sender (for your cluster) is 83320-35020 as said before. If you use a different tank you'll have to bend the float arm to an acceptable reading that works for you.
You don't mind if the FULL indication is correct. You want to know when your tank is almost empty.

Rudi

I disagree with all of above?????

 

[nuclearlemon]

BTW, here's some Gee Whiz information: Many, many buy the rear aux tank/fuel cell to be used as their one and only stand-alone tank. Minor reason, it's 22 gallon. Another minor reason, it gets fuel/fumes outside the passenger compartment. Major reason, anybody over about 6 ft. tall looks out the top of their windshield at about wiper blade level. They can't lower the seats because of the interior tank. No interior tank allows righteously mounted bucket seats.

yeah, but the tanks on the passenger side. they don't need to look out the w/s

only had an issue with fumes in one rig and that's because the hose was cracked. if you have fumes, you need to fix something

 

[Downey]

yeah, but the tanks on the passenger side. they don't need to look out the w/s

only had an issue with fumes in one rig and that's because the hose was cracked. if you have fumes, you need to fix something

You must have missed "Righteously Mounted", drivers seat lower than passengers seat is not righteously mounted!!!!

 

[softdrinkviking]

I disagree with all of above?????

OK, thanks everyone for the input.

How about bending the sending unit until it registers closer to the proper level?

Is the sending unit tied to a specific tank capacity?

Does anyone know if the new replacement gas tanks that are being sold currently are 16 or 18 gallons?

 

[tony58]

I guess I will remove the sending unit next week and will test it with a ohm meter to see if that is my issue, I do see that city racer has them. Any help on how to put the speedo cable back on I heard it is a Pita. Thanks

 

[tony58]

One other thing is there a voltage regulator on the panel that could be at fault?

 

[Racer65]

One other thing is there a voltage regulator on the panel that could be at fault?

I'm not familiar with the whole circuit, but I can tell you that measuring the resistance won't give you the answer.
I've had some folks tell me the resistance of the factory unit isn't "correct", but all units are the same way. I think there must be a resistor by the gauge cluster. Anyway, someone told me he fixed the issue simply by bending the pivot rod of the sender.