I transplanted the fuel tank from my 86 GT into my 90 GT in order to get her running. And the results was COMPLICATIONS... Actuallythe problem is that my fuel guage is completely wacked. FULL = needle below E and slowly moves upward. When it reaches just bellow 1/2 tank = EMPTY. I'm guessing that there is a difference in sending units (diff. guages = diff. sendimg units). Does anybody know for sure? Bad news: I do not have the 90's tank or related components. Any help would be appreciated.
PS: I know there is a similar thread open, but i didn't want to jack good ol joes90gt's post.

 

so your saying at full tank, the gauge shows empty, and slowly rises as the level gets lower, then once you're at half tank it drops normally?

 

if you are using the 86's sending unit = no can do!!! the resistance values are different on the 86 vs the 90's fox stang, you need a sending unit calibrated for your application = go buy one for your year make and model and prob will be solved

 

no, i poorly worded that.

Full tank is represented as E on the guage and an Empty tank is represented as 1/2. The needle slowly rise until I run out of gas (thats when the guage registers just below 1/2 a tank of gas).

 

The sending units are definitely different. I learned the same way you are now.

 

Are you refering to my post?? cause I gave you the answer

 

Thats what i was looking for. Thanks man. I've been having trouble locating one, I huys its a trip to the bone yard.

One more. Is there a diff. between the 4 and 8 cyl sending units for the same year application?

 

not sure you can try one out of a 4 popper my 92 is a 4cyl conversion and I converted the cluster, meaning I left the fuel gauge , oil, volt, and temp for the 4cyl in the cluster and swapped out the speedo and tac, if it doesn't work just buy one from 50resto.com

 

5.0liter_rice_eater......I appreciate your respect, I wouldn't have been offended. After all, were just looking for the same answer!

After mjr46's advice I may just drop the tank and replace the unit.

 

I posted this a while ago, but I have an update. I replaced the sending unit with one from another 90 5.0 and now i have a new set of problems. The gauge reads random levels at start up and then sinks to 1/4 tank and sits there. I did notice that when i actually get to a 1/4 tank or less it will drop to empty as it should. Any suggestions?