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Digital Dash Question

Hi everyone

So my 87 xr7 is having an issue with the fuel digital dash section. It reads "U" !!!!

I talked with Eric of CoolCats and he was awesome and said it is probably the sending unit but was not sure as he never heard of the dash reading "U". Has anyone here ever experienced this same issue? I have already purchased the entire fuel pump but was curious if the community on this site could offer any words of wisdom?

Thanks again,

Cody
C3Brix

Digital Dash Question

Reply #1
The sending unit is separate from the pump.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Digital Dash Question

Reply #2
Can you post up a picture of the dash showing the "U"?

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Digital Dash Question

Reply #3
Yes, I'll get it up soon, but it is just saying U were it would usually say F "full"


Quote from: Aerocoupe;459033
Can you post up a picture of the dash showing the "U"?

Digital Dash Question

Reply #4
I thought the sending unit was in the pump? I checked at autozone

Digital Dash Question

Reply #5
Nope, the sending unit is smaller on the passenger side of the tank, the fuel pump is bigger and on the drivers side.

Newer mustangs and most gm's it was built in.

Now ro make it more confusing, buttstuffog fuel guage is a different sending unit. The turbos also had a 19 gallon tank and the earlier cars were 20.6 gallons instead of 22.1 like the later cars.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com


Digital Dash Question

Reply #7
in my diy link below...... entering the code pulling of the multi guage.

=========================
Tach/Multi guage diagnostic

 all codes are Hexadecimal format and can range from 00 to FF (binary 0000 to 11111111)or (decimal 0 - 128) . While active in the various modes, they can be used as a "wiggle test" to check for shorts and intermittant circuits. Anyway,, display will be in hex format.

 hold the guages button in and turn the ign key to RUN
 Advance through the tests by pressing the guages button.
 A steady Tone and 8 bars lit is a passing test
 No tone with 24 bars lit is a fail

 To enter the Fuel computer self test
 Press and hold the Select button atleast 5 or so seconds until the test display appears then advance thru the tests by pressing on Select over again.

>>>>>>>>>>
I never did do a personal write up on how to enter the fuel system code pulling part but i can or look it up for you

I would have to look up what "U" means in the shop manual.

For what its worth, in my resto project in "engine swapping", and i think inside "electrical tech"... Summit has a great solution for senders.

phone number for me is 304 772 3411
i work from my home office so no realy time limits on when to call.

Digital Dash Question

Reply #8
Shop manual has no listing for "U" on the display, BTW. It seems very specific, as far as the issue here, but I've not found a similar occurrence in the manuals.

Digital Dash Question

Reply #9
Thankyou so much for the info. I will keep you posted on the results. I don't want to bother you but if I think I'm doing it wrong I might give you a buzz. 🙂


Quote from: jcassity;459088
in my diy link below...... entering the code pulling of the multi guage.

=========================
Tach/Multi guage diagnostic

 all codes are Hexadecimal format and can range from 00 to FF (binary 0000 to 11111111)or (decimal 0 - 128) . While active in the various modes, they can be used as a "wiggle test" to check for shorts and intermittant circuits. Anyway,, display will be in hex format.

 hold the guages button in and turn the ign key to RUN
 Advance through the tests by pressing the guages button.
 A steady Tone and 8 bars lit is a passing test
 No tone with 24 bars lit is a fail

 To enter the Fuel computer self test
 Press and hold the Select button atleast 5 or so seconds until the test display appears then advance thru the tests by pressing on Select over again.

>>>>>>>>>>
I never did do a personal write up on how to enter the fuel system code pulling part but i can or look it up for you

I would have to look up what "U" means in the shop manual.

For what its worth, in my resto project in "engine swapping", and i think inside "electrical tech"... Summit has a great solution for senders.

phone number for me is 304 772 3411
i work from my home office so no realy time limits on when to call.

Digital Dash Question

Reply #10
I was just trying to help and Eric found what i did as well.. no "U"

I did however find some other information within the same shop manual section and so i have to ask..

can you enter the diagnostics... "watch dog" testing?

If what i am thinking is correct, you may actually have what the shop manual is referencing as ghost images.... where you see a U but an 8 would need to be seen.

one of the tests is a wiggle test by the way.

and for the record, until you inspect the flex print on the back of the cluster or a loose harness wire, you may be shot gunning it. 

Where does the "U" show up,, where you would normally see your total gallons/liters?
when you hit the guages button does *EVERYTHING* else work correctly???

as a side note i have noticed that if ever you have 4 bars on charge,, your alternator is going out or is under a lot of load.