fuel sending unit

Topic: fuel sending unit (Read 4165 times) previous topic - next topic

fuel sending unit

Reply #45 – January 10, 2009, 02:47:57 PM

Well it started as a wanting a fuel sending unit, lol It kinda took life and spread out to a help thread.

fuel sending unit

Reply #46 – January 16, 2009, 01:23:41 PM

Alright, well i have potential god news. I drove the car to the gas station and filled her up. It took 9 gallons on top of the 15 or so that were already there. The needle went above full, like it used to.

So i'm going to teeter the thought maybe its working that just on E there are 8-10 gallons remaining. I'm going to drain some of it and see if it goes down. If it goes down, I'll assume its working, an just remember mileage for a few tanks and see what happens.

fuel sending unit

Reply #47 – January 17, 2009, 12:31:00 AM

Alright well its settled. My gas gauge goes from full to empty in 10 gallons. If its full at 22 gallons, the needle will move from full to empty if i remove 10 gallons. That means on "E" I technically still have around 12 gallons in the tank. Who knows why this is like this, but it is. I syphoned out the gas and watched the needle today.

I'm assuming the sending unit is screwed up. I have the digital one laying around, how do you convert that to an buttstuffog one? I would like to do that and try that sending unit, see if I get a better representation of whats in the tank.

Thanks for all the help guys.

fuel sending unit

Reply #48 – January 17, 2009, 08:08:46 AM

Your float arm could be bent upwards to much for some reason.
Was your float spinning freely when you put it back in?
Or it could have been not originally from a cougar at some point?
mabe from a smaller tank car? I don't know what might have been compatible with it in it's day. Capri mabe?

fuel sending unit

Reply #49 – January 17, 2009, 01:13:48 PM

Well its a thunderbird, but the float did spin freely when it was put in. I believe the sending unit is original but it could have been replaced when my grandmother had it. I know it came out of a 21 gallon tank. There is a little difference in the replacement tank, but that shouldn't matter a whole lot.

fuel sending unit

Reply #50 – January 18, 2009, 02:04:23 AM

check out paragraph 2 of post 41 once more. We reply and ask questoins but your not giving resutls back.

fuel sending unit

Reply #51 – January 18, 2009, 08:27:08 PM

Quote from: jcassity;252317

check out paragraph 2 of post 41 once more. We reply and ask questoins but your not giving resutls back.

Sorry. I started school and haven't gotten a chance to follow all of the electrical testing advice. Hopefully I will let you know next weekend.

fuel sending unit

Reply #52 – January 18, 2009, 10:06:52 PM

No problem, you know where to find us

fuel sending unit

Reply #53 – January 19, 2009, 12:01:19 AM

I didn't want you to think I was ignoring you cassity, just need to find the time to drop the tank and be able to test everything. lol

fuel sending unit

Reply #54 – January 19, 2009, 01:26:24 AM

i didnt say to drop the tank.

fuel sending unit

Reply #55 – December 05, 2016, 02:28:26 PM

Quote from: daminc;250284

Digi
first one is 60 deg.
2nd one is 130 deg.

buttstuffog
first one is 50 deg.
2nd one is 140 deg.
starting and stopping levels are the same.
as long as you use that formula. It should be OK
I'll get a pic later tonight

jpc647
This may be the reason for your tank reading.
You should check to make sure both of your senders start and stop at the same place. I'm not sure if a sender from an 18 gal. tank is the same as one from a 22 gal. tank, or where the diff in tanks are.
also
I should have told you to clean the contacts in the sender before putting it back together. I had to do that in mine, because it sat for so long without being used past the 1/2 mark. I wasn't getting a good reading.
I just took a pencil eraser and shined up the entire board in the unit. the rheostat will get a build up on it where the arm hasn't traveled in a while.

unfreaking believable how the information we have floating around here is so valuable.
THe angles posted above are finally years later getting checked.

Thank you daminc!

fuel sending unit

Reply #56 – December 05, 2016, 02:34:19 PM

update to my earlier idea...
i have found it impossible to find a variable resistor in 1/3 of a turn with the resistivity we need off the shelf.
ive looked on digikey , and several other electronics supply houses.
im sure im missing something but its not easy.

fuel sending unit

Reply #57 – December 29, 2016, 11:35:02 AM

UPDATE from foureyedpride.com
a guy there sourced Dorman part number 692-120 in order to obtain the ceramic PCB needed to fix his issue.
this is fyi only,, his ceramic PCB is a reverse negative of what we need for buttstuffog guages from what i can see.

liny / read / pics / details here >
http://www.foureyedpride.com/joom/index.php?option=com_content&view=article&catid=25%3Atech-art&id=105%3A83-86-cfiefi-fuel-sender-repair&Itemid=42

foureyedpride's contributor JACook did a lot of research to repair his CFI 83-86 application.

fuel sending unit

Reply #58 – December 29, 2016, 02:43:58 PM

Update again,
i just ordered this from summit racing

https://www.summitracing.com/parts/sum-290260/overview/

Knowing this one is backwards, yet the price is low, i suspect the rheostat is 100% linear therefore cheaper to make.
in our cars, there is a lot more resistance on the upper and lower 25% of the PCB and you can see this when you notice it takes a while to come off the F mark and it also takes a longer while to go from 1/4 tank to empty.

in this unit i bet its very smooth and drops the fuel level "as you use it".

I will expect i have to simply move the wire from one end of the PCB to the other making it a 90ohm empty, 0 ohm full.
I will expect to need to calibrate the arm so that when the float hits the top of the tank i will "force" the sender to read 8 ohms.

49$ later and give it a few days shipping sometime next week and i will update you all.