OK, all new Motorcraft tune-up parts installed
including plugs, wires, dist.cap/rotor, & TFI still
didn't make the TC run right, but they were original
40K mile/26 yr. old stuff & they were in dire need
of replacement. Diagnostic testing showed the fuel
pump was bad, so it was replaced & VOILA, the TC
now runs like a 40K mile TC should!!! :D
Only problem is, I forgot to tell the mechanic the fuel
gauge didn't work! Doh! I don't know if there was
anything he could have checked out while installing the
fuel pump or not, but too late now.
The gauge just stays on empty even though the tank has
just been filled up!
Is there a sending unit in the tank that could be bad, or
would it be the gauge itself? Probably my luck it's a problem
at BOTH ends.
Thanks in advance for any help with this.
Jeff
There is a sending unit in the tank, and they definitely go bad quite often on these cars after 25+ years.
And evidently it's separate from the fuel pump, and I should have
had my mechanic check it & install a new one YESTERDAY when he
installed my new fuel pump! grrr :(
I know it's going to drive me crazy, but it will have to wait for a while.
I'll just keep resetting the trip odometer as always at each fill-up.
Thanks for the info 20thanniver-ls.
Jeff
It is in fact separate from the fuel pump, I'm pretty sure you can still buy new sending units, try rockauto.com if you're having trouble elsewhere .
I am sure they are obsolete. Not 100%. But you will need a resister unit of 10-80 ohms to make it work if thats the problem.
You may be right. I think what I got from rockauto was just the retainer ring....
http://www.dragtimes.com/parts/1986-1987-1988-Ford-Bronco-II-Fuel-Tank-Sending-Unit_220690823465.html
THis is what i would use!!
looks good for a conventional cluster , could be modified to accommadate the full digi but thats a different thread.
it says it's for a 23 gal tank...wish I had one of those to compare to ours........ on the ongoing quest for modding and replacing these
to be honest, its a wash ,, the difference between 21 and 23 gal may mean the difference between two or three ohms.
One thing is for sure, I know darn well why its for a broncoII, and not a bronco.
I also would like to complete the testing and reversing of common senders to include the additional resistivity required for the full digi cluster.
atleast we have some decent documentation on what is known, I never have gotten my hands on a unit that can be modified as of yet.
I decided to finally check the owners manual & fuse # 17 (blue 15amp) is for
the fuel gauge! Went to pull it, & it's missing! To make matters even worse,
when I went to pop a new fuse in, the part that the steel pr0ngs slide into
isn't there!!:( It's like someone broke out the holder part when they pulled
the old fuse!
No wonder the fuel gauge doesn't work.
If you have an buttstuffog gauge there is no fuse.
The 85 EVTM says fuse 17 is not used on 2.3L unless you have ATC.(Automatic Temperature Control)
hold on! This could be an early 85 thing. The 84 EVTM shows fuse 17 supplying power to the buttstuffog cluster IVR.
The 84 cluster has a fuel gauge but just a light for oil pressure and coolent temp.
The 85 has gauges for fuel, oil and temp. If you have the three gauges and the other two are working, then you have power to the IVR.
According to my '85 owner's manual, fuse #16 is for the Electronic ATC.
Fuse #17 is for Electronic Cluster, Tripminder display module, OR fuel gauge on Non-electronic Cluster!
Yeah I hear you. There is confusion in the documentation.
But if you have three buttstuffog gauges (non-electronic) they all use the same power source.
I think the Tech writers could not keep up with the changes.
OK, thanks for the help.
Guess I'll just keep looking for a new sending unit.
I don't know if its worth looking at or trying but i was looking on ebay at the universal unit......I never experimented with them so i wouldn't know....:confused: http://motors.shop.ebay.com/i.html?_nkw=fuel+level+sender&_sacat=6030&Model%2520Year=1986|1985|1984|1983&Model=Cougar&_dmpt=Motors_Car_Truck_Parts_Accessories&Make=Mercury&_odkw=fuel+level+sensor&_osacat=6030&bkBtn=&_trksid=p4506.m270.l1311 (http://"http://motors.shop.ebay.com/i.html?_nkw=fuel+level+sender&_sacat=6030&Model%2520Year=1986|1985|1984|1983&Model=Cougar&_dmpt=Motors_Car_Truck_Parts_Accessories&Make=Mercury&_odkw=fuel+level+sensor&_osacat=6030&bkBtn=&_trksid=p4506.m270.l1311")
If you want to do a little trouble shooting:
In the trunk under the rear window package tray.
Find a two terminal gray connector with a yellow/white stripe wire and a black wire.
One side of connector, the wires go to the sender in the tank.
The other side of the connector the wires go to the fuel gauge (yellow) and ground (black).
Unplug the connector and jumper the yellow and black wires together on the side going to the fuel gauge. (It won't hurt anything if you guess wrong on which side is which)
Turn the ignition switch to RUN and the fuel gauge should peg to the full side.
Just leave the ignition on long enough to confirm the gauge works.
On the side of the connector going to the sender, check the resistance between the yellow and black wire.
The specs for the sender are:
60 to 86 ohms empty
8 to 12 ohms full
Looks like the 85 has no fuse but a 8.5 OHM resistor. Their is a circuit change according to ALL DATA.
Ford discourages shorting the wires together without resistance. Could burn out the gauge. Uuse a test light which is app 10 OHMS. I have the ford variable test BOX that is calibrated for the tank units. A trip to radio shack can get you a variable POT and you can use that. You will need something like 0-100 OHMS. Good luck
I would try the sender Tom posted first
Those low OHM units are hard to find. But you can use the Bronco 2 and i think that can be modified to work. Their is no other option the sender is OBSOLETE. I have 2 left and i am going to hold on to them. The midnighter has a bad one i will be changing this weekend. Good luck on your FIX
https://www.classicinstruments.com/productother.aspx?ProductCode=SN39
How about this one. I think it should be OK
The 85 EVTM shows the 8.5 ohm resister wire between the ignition switch and the IVR.
The 84 has no resister and has the same specs 8 to 12 ohms full for the sender.
So I figured there was enough current limiting with the resister wire.
But you are correct, to be 100% safe you should use some kind of resister for testing.
These gauges are heavily dampened and move slow. You can probably turn the ignition off before it reaches pegged.
might as well pull this old thread into the mix so its up near the top again,,
completely applicable to the problem but i am very interested in the 84/85 changes. Ford is terrible for documentation errors or just plain year to year changes.
http://www.foxtbirdcougarforums.com/showthread.php?22137-fuel-sending-unit/page5