Fox T-Bird/Cougar Forums

Technical => Electrical Tech => Topic started by: Ductape91 on March 09, 2023, 12:02:19 AM

Title: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on March 09, 2023, 12:02:19 AM
I cannot find a fuel sender for my 83 thunderbird anywhere, new or used buttstuffog or digital one. Searching for one is holding me up from throwing my new gas tank in among other things.
Mine currently works, but it might not tommorow because its a 40 year old part so i wanted to put another one in and keep the original in case its not in good physical condition when i pull it out.
To be honest i dont really see any senders being made for these cars of any year.
Searching around i dont see much discussion about what others have done in this situation with regards to making something else work other than just with the actual sending unit and float component itself.
Ive seen the sender ohm signal devices people use with custom tanks and gauges that arent much money and simple to wire in.
But that wont solve a rotted fuel tube or top plate problem or similar issue.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: softtouch on March 09, 2023, 03:33:43 PM
Don't know where you can get one, but if you use the wrong one, digital/buttstuffog, the gage will read backwards.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on March 09, 2023, 04:03:58 PM
Don't know where you can get one, but if you use the wrong one, digital/buttstuffog, the gage will read backwards.

They sell devices you splice in and calibrate to fix that issue.

https://youtube.com/watch?v=xCQhoJw6MhA

Edit: put a proper link in describing how to and functions of this device.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: softtouch on March 11, 2023, 04:51:44 PM
Very interesting. I am surprised there is that much demand for that.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on March 11, 2023, 05:24:15 PM
Very interesting. I am surprised there is that much demand for that.

There are cheaper versions of these devices out there but i dont believe they have all the features of this one in particular.
Looking around for many months for the "correct" sender while passing on what was floating around at the time(they were nos to boot) on what would fit but werent "correct", and then finding out about these devices but the ones that wouldve fit are long sold now hits kinda hard.
Now im trying to figure out what fuel senders have the depth, plate size, range and outlet direction and number of outlets the oem one does to find a compatible one.
Digging around the service manual cd i got shows 2 different sender types, one with return line for the tripminder and one with out.
I havent been to my tbird garage in a bit to measure the tank depth or proximity of the sender hole in relation to possible positions for options so im hoping i can scrounge up the time to do so.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: mcb82gt on March 13, 2023, 09:51:29 AM
Ive heard of companies that rebuild the senders, but I dont have any experience with any.

Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on March 18, 2023, 09:13:38 PM
Ive heard of companies that rebuild the senders, but I dont have any experience with any.



Ive seen this brought up or mentioned in every corner of my searches yet not a single company or service was ever said.
I havent searched for this specifically myself since im still holding out on obtaining one or making one work at this time. Hopefully tomorrow i can drop the tank and take the old one out to measure it and see what i can make work.

Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: mcb82gt on March 20, 2023, 10:34:38 AM
https://desertclassicparts.com/fuel-sending-unit-rebuilding-service/
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: mcb82gt on March 20, 2023, 10:46:57 AM
https://www.bobsspeedometer.com/services/fuel-senders/
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 10, 2023, 01:53:10 AM
So, an update to this subject since im starting to get the things i need to complete this job.
After removing the original fuel sending unit and inspecting it carefully i decided on replacement.

The original unit.
(https://i.ibb.co/pnjz3YW/20230401-183607.jpg) (https://ibb.co/st9wF85)
(https://i.ibb.co/HtY0Q5c/20230401-174208.jpg) (https://ibb.co/3pWwHgx)
(https://i.ibb.co/QCz8sFg/20230401-174158.jpg) (https://ibb.co/1dhsHfg)

The wire lead onto the arm rotted off into dust just sitting in the bag im keeping it in and the inlet tube is clogged up with rust and crud some ways up the tube.
With no available store bought solution for these cars i will have to make another work.
The original one has a 5/16 tube and is 10" long from the plate bottom when unbent, sits about 6" into the tank when installed( the tank is 7 3/4" deep from the lockring) and the outlet tubing is 1 1/2" high from the top of the plate.
Resistance of the original is 10Ω empty and 160Ω full. I have no clue what that extra wire on the swing arm was for but its gone now so i have no info on it.

After careful consideration i selected the two closest possible replacement senders i could find that fit most of the necessary parameters to work with the means i have.
The necessary parameters are as follows:
Must have the same plug/connector as the current vehicle. Most of this vintage have a male 2 pr0ng plug on the sender and would require me replacing the original connector. For some reason all the images i could find of a correct replacement connector had locating tabs not in the spots as the original so im hoping that wont be an issue.
Must be 5/16 tubing. 3/8 would be acceptable if all other parameters match since its not like a fuel injected car and i got to worry about fittings and such.
The outlet must face as toward the front of the gas tank/vehicle as possible in the same manner of the original.
The inlet tube must not be rearward facing in the tank as the original doesnt and the tank design wouldnt allow for accurate readings.

The ones i chose was from an 84 bronco II, and the other is from an 84/85 Carbureted v8 mustang.
Im still waiting for the mustang one to come so im figuring out the bronco II one atm.

(https://i.ibb.co/QXrdvk7/20230410-010848.jpg) (https://ibb.co/YbpZBX4)

The 84 bronco unit has a single 5/16 outlet that is 1 1/2 high and faces directly forward, unlike the originals which is slightly to the drivers side. Shouldnt be an issue requiring bent hose to fit cleanly.
The tube is 13" long from the plate bottom and is completely straight/unbent from the factory.

(https://i.ibb.co/T8zHyYm/20230410-004941.jpg) (https://ibb.co/KqC9nbF)
(https://i.ibb.co/p2Gn73g/20230410-004903.jpg) (https://ibb.co/Jn0C1zN)

I forget the exact resistance values on it( i believe its 80Ω empty and 10Ω full) but thats irrelevant since im changing it to a different one. I "was" going to use the fuel sender correction device, and if my plan doesnt pan out i may still have to, but i located a sending unit with "almost" the same values as the original and am going to try and make that work with some creative soldering. Ill be using quality stuff so im not worried about the strength of it.
That sending unit is from a 99+ mustang, which has a resistance value of 15Ω empty and 160Ω full. Hopefully that 5Ω wont make much difference since i couldnt find one that was in the correct 10-160 range and would physically work.

Now onto the 84/85 mustang carbureted fuel sender. Ill update part when the unit finally comes since the mail has been slow.
That one was selected because it may either be in 5/16 or 3/8 for some reason but probably will be 3/8, has TWO outlet tubes in mostly the correct direction for people that may have the rare tripminder option still working or just a need for a return line on their car, and the inlet tube is easily long enough to be cut and bent to correct orientation to work correctly. It will require less work to work but we will see.

Stay tuned.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 14, 2023, 11:46:46 PM
Took apart the original to try to clean it up some and finding it filled with chunks of rust, and the spring arm broken from just sitting around so now it doesnt work at all.

(https://i.ibb.co/bm75WcN/20230412-225421.jpg) (https://ibb.co/B3w2z0T)
(https://i.ibb.co/5sn8xRf/20230412-225432.jpg) (https://ibb.co/7rRWN16)
(https://i.ibb.co/37CpyrK/20230412-225437.jpg) (https://ibb.co/DtR9DVd)

Great. Im going to look into one of those rebuild services and see what fixing that will run just to have a working original handy.

Some progress though, Today i cobbled the new unit together.

Dismantling the 84 sender and cutting it to size.

(https://i.ibb.co/99KC6t7/20230412-210713.jpg) (https://ibb.co/3y6L2zn)
(https://i.ibb.co/GJv4s9t/20230412-211821.jpg) (https://ibb.co/Ct53J6M)
(https://i.ibb.co/yqzLPMc/20230410-165331.jpg) (https://ibb.co/jDC7fxP)

Fitting up the 99+ mustang sending unit to the 84 bronco II sender. I soldered it to the tube since i dont got the stuff to weld stainless here. The solder is pretty strong when its done right.

(https://i.ibb.co/8Ngrc8V/20230414-220048.jpg) (https://ibb.co/ZGzBmTC)
(https://i.ibb.co/Dtbc20X/20230414-231104.jpg) (https://ibb.co/rmt8rDP)

The soldering worked better on the stuff i tested it on at work since i had a nice torch there and a vice to clamp stuff together.

(https://i.ibb.co/BzcJp1L/20230414-002421.jpg) (https://ibb.co/tmQ6GdB)

That is a pic of some trash parts left from the new unit i tested the solder on after we bashed it around on the welding table and vice for awhile to make it break. It didnt and will definately hold together in the gas tank environment.

Here at home the pipe sweater tip and holding it by hand to do it just wasnt good enough to be satisfied with but it still worked, for now.
Testing the unit resistance after i bent the arm to fit into the range it needs to move inside the tank.

(https://i.ibb.co/YkQRWRj/20230414-231227.jpg) (https://ibb.co/Hz4F2Fg)
(https://i.ibb.co/pPThbv4/20230414-231304.jpg) (https://ibb.co/sP4Wbvs)

Now i just have to get to the garage and plug it in so i can see it in action.
If this works like i expect ill make another at work since i have the stuff and space to make it right and last forever.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 15, 2023, 04:25:58 PM
Went to the garage to test fit and check everything.

(https://i.ibb.co/6wP4MwD/20230415-142715.jpg) (https://ibb.co/jfMLNf3)
(https://i.ibb.co/WKYW1Vs/20230415-142842.jpg) (https://ibb.co/JkMRP3C)

Testing the sender to dash.

Full.

(https://i.ibb.co/T8DxkZd/20230415-143858.jpg) (https://ibb.co/FwkLK9C)
(https://i.ibb.co/D4pNT5Y/20230415-143912-HDR.jpg) (https://ibb.co/xhHydJY)

Empty.

(https://i.ibb.co/F6vwRTb/20230415-143302.jpg) (https://ibb.co/9nXTQ59)
(https://i.ibb.co/7jn3j8D/20230415-143308.jpg) (https://ibb.co/k54L5kT)
(https://i.ibb.co/9WQKwq7/20230415-143951.jpg) (https://ibb.co/Zxq4Hh0)
(https://i.ibb.co/znLLy3G/20230415-144027.jpg) (https://ibb.co/RvMMxXz)

It would show between single/two bars when full empty, low fuel light worked and the flashing gas can thing when low

It worked in any position and showed up on the dash appropriately but i couldnt make the dash change when i swept the arm. It would only change on the dash when i shut the car off and turned it back on.
I cant check with the original to see if that is normal for it.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on April 16, 2023, 08:58:02 AM
IIRC the digital gauges sweep a couple of times a second. There's probably a delay in there somewhere and I'd bet that's it. But you may be right, ignition on might initiate the sweep. You'll know as soon as you start driving it.

Otherwise...this is an awesome job overall, you're undoubtedly going to help others here with the same issue.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 16, 2023, 02:12:21 PM
I hope so, I was thinking maybe anti slosh might be the reason for no sweep but this car is too old for that.
I'm still waiting for the carbed mustang sender to come so I can make that work.
Another thing to note is the connector for the sending unit from the car broke the clip that holds it on while I was messing with it, just ultra fragile plastic plug after 40 years, they sell replacement ones that have the side tabs in the correct spots but I cannot find a replacement rubber gasket that goes inside the connector since the new sending unit didn't come with one.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Haystack on April 16, 2023, 08:52:18 PM
Not saying this is the right way, but I had my fuel pump die on the side of the road and the clip disintegrated. I clipped off another clip, but there was not gasket at all. I ended up using a 20v hot glue gun.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 17, 2023, 01:11:47 AM
Not saying this is the right way, but I had my fuel pump die on the side of the road and the clip disintegrated. I clipped off another clip, but there was not gasket at all. I ended up using a 20v hot glue gun.

I actually have a small can of liquid electrical tape I was going to "fill in and paint it up" with to make a gasket if I can't find one.

In case anyone needs to do so if they break theirs the replacement fuel sender connector is standard motor products #903 for mustang fuel senders, says 87-93 but other vehicles used that connector. The #904 is the repair connector for mustang fuel pumps but has offset locating tabs so it won't fit without tpuppies one side of it.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on April 24, 2023, 01:37:52 AM
So i got the 84/85 mustang gt fuel sender a few days ago and began some work on it to "make it work" in the tbirds tank.
The sender has 5/16 and 1/4 outlets and was 18" long from the bottom of the plate.

(https://i.ibb.co/nckQwGZ/20230418-222342.jpg) (https://ibb.co/58cs10t)
(https://i.ibb.co/xzRf7MK/20230418-223646.jpg) (https://ibb.co/mhMXcHr)
(https://i.ibb.co/68pXJLb/20230418-223724.jpg) (https://ibb.co/dt3mJx6)
(https://i.ibb.co/3hvWF9Q/20230418-223732.jpg) (https://ibb.co/5ckvjgw)
(https://i.ibb.co/JvpW2dP/20230418-224714.jpg) (https://ibb.co/3pF5WsH)

I might pull that up some with a bender since that is the max depth of the tank.
Im having a hard time finding the sweet spot to make the senders arm sweep work in the space in the tank before i solder the sender on. I may have to get creative with it and swap the arm with the one it originally came with.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on October 17, 2023, 04:07:28 PM
Any updates to this? Inquiring minds want to know. :)
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 18, 2023, 02:00:40 AM
Any updates to this? Inquiring minds want to know. :)

I got a bit sidetracked.
I havent had the car out since i replaced the gas tank and had that break down incident, ive been working on my other car in the meantime because all the stuff i was waiting for came for it.

Im making time to get back at the tbird, and i have to grab the parts again to finish this other fuel sender with return line. Finding the sweet spot to mount it was the issue i was figuring out when i stopped.
The first fuel sender i put in was working, but i need to run a few tanks thru it first.
Ill have updates soon.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on October 18, 2023, 09:24:24 AM
Groovy, thanks.

So the electrical connector on the Mustang sender...it is the same as your stock T-Bird one?

I'm currently writing an article about replacing fuel system components for the website and like you, I found that some of these units  (especially the fuel pump with sending unit combo) are just not directly replaceable. And it doesn't help that 1983-84 components seem to be unique. In those instances you'd either have to modify something else, as you're doing, or have your stock one rebuilt. One of the big 'ifs' is that connector and I'm just trying to clarify from your experience with these.

I just had my total fuel system replaced...new tank, hanger assembly, sending unit. Luckily these are still available, although I had to install a used filler neck as they're not available new anymore. I was fortunate and got a Mustang sending unit to work without much issue.

I've also heard that Tempo/Topaz senders might work, haven't verified that though.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 18, 2023, 01:01:57 PM
It should be, but ill double check on that.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 18, 2023, 03:33:49 PM
They are the same.

(https://i.ibb.co/hCgZBVQ/IMG-20231018-141238239.jpg) (https://ibb.co/cxyC6Qf)
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on October 18, 2023, 04:31:39 PM
Awesome, thanks for the verification.

So in your opinion, if someone had an buttstuffog gauge in an early car (1983-85) and wanted to use a Mustang sender, is that the most feasible route for a brand new sender, with modifications of course?
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 18, 2023, 07:12:53 PM
If they didnt need the return line they could probably use the bronco II one right out of the box just "bending" it to shape for an buttstuffog cluster.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on October 19, 2023, 09:33:37 AM
Alright, good. And if they do need a return line...?

(Guessing it's going to be either an experiment or getting the old one refurbished using a service. Or use a Fox Mustang sender and modify.)
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 19, 2023, 11:24:22 PM
I havent finished making the mustang fuel sender yet, so i cant say for sure yet on it.
They do make add on fittings that install on aftermarket efi fuel senders for custom tank jobs, im looking at those right now as well.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: EricCoolCats on October 20, 2023, 09:56:40 AM
Ahhhh okay, hopefully something Mustang-ish works as that's going to be a future-proof solution for us.

I've had my eyes on this super-cool aftermarket fuel level sender...
https://www.holley.com/products/gauges_and_gauge_accessories/gauge_accessories_and_harnesses/parts/19-250

...but here's the rub:

Quote
Easy to program the level of any tank and electronic gauge - does not work with OE style gauges that utilize an ohm only input

Understood why it needs an aftermarket gauge, because those run straight off 12v and don't really care about the ohms coming from the sending unit. Since we're dealing with a stepped-down 5v gauge and different ranges of resistance, it's unclear if this could even be adapted to our cars. But I absolutely love this concept though.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on October 20, 2023, 03:08:54 PM
I looked at fully aftermarket senders and they all had something that said this wont work for me. Most require cutting a new hole in the tank for them, which i wasnt going to do even though it was a new tank.
Im going to smuggle the mustang sender stuff back into work so i can finish it.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on November 15, 2023, 05:54:33 PM
I finally have some time off this weekend so i can take out the car and fully test out the sender.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: jcassity on November 26, 2023, 09:02:57 PM
this thread is a keeper the the ultra hard to find info on cluster.  I used the summit general purpose sender for my "other" 87 coug.,, not my 20th.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on November 26, 2023, 10:55:49 PM
Sorry i didnt get the car out, was offered some OT i couldnt turn it down and it was just a nightmare on the roads around here this holiday weekend. My daily was also giving me issues i had to take care of as well.
Just bad timing, ll try again this weekend i have to get it out and get the drivers window fixed anyway.

Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: Ductape91 on December 03, 2023, 08:09:33 PM
 :mullet:

Success, She works. Gauge went down from under 3/4 full during my drive and while idling in the garage for like an hour playing around with the car in there.

(https://i.ibb.co/JvYNkfc/IMG-20231203-185340482.jpg) (https://ibb.co/bs4xdS6)

Probably wouldve helped to have a before pic but i left my phone at the garage when i took it out, and had to come back for it. Got back and started ripping the door off to fix that but the gauge reads and moves like its supposed to.

Now the real work begins, making another based on my own posts and info here to see how repeatable it is for the next guy.
Title: Re: 83 Digital Dash Fuel Sending Unit Options
Post by: jcassity on December 04, 2023, 08:59:31 AM
the 83 digi cluster....  so little information out there on these displays,, or should i say available working units.
I'd say your propably one of a handful of ppl on earth who has one.