[Maxson]

Quick question before I start unbolting things....

My fuel gauge is pegged deep to the right past FULL and does not move regardless of how much gas in the tank. I figure the problem is wire grounding out somewhere... I just noticed something I wanted some opinion on though - when I turn the car off, the needle doesn't move.

If a wire were grounding out somewhere, wouldn't the gauge return to the left, starting position when the ignition is killed?

Anyone have this same issue before? I am unsure as where to start my troubleshooting now...

 

[Redwagon]

Its a common issue with broncos...and it usually ends up being a bad sending unit, you can either drop the tank or cut a hole through the floor to replace it, a quick search will find you info on both ways.

 

[Maxson]

Aye, that is another possibility I was looking into... I had searched previously for answers, however I was confused with the needle staying on FULL even with the ignition switched off....

 

[BigBroncoXLT]

:stupid if let go long enough, It will cause other problems. Mine melted the ground wire to the power wire and then melted the gauge face

:shocked

 

[Maxson]

Great info on the neutral positions Steve... thanks for taking the time to post AGAIN on this topic - I have been reading your posts all morning....

:beer

 

[BigBroncoXLT]

Steve, it ended up being a short at the sending unit itself. Thanks for the help on that. I had never seen one melt the gauge face. I had to rewire a good portion of my fuel gauge circuit in the frame where it burned the wires up at the tank. Guess I never payed any attiontion to the neutral position, except now that you mention it, when I was repairing the fuel gauge circuit I had my wife in the truck watching the gauge she would tell me that it would read full, but when open it would go to empty.


Shouldn't his gauge read empty, being that is the neutral position?

 

[BigBroncoXLT]

I didn't know that all the gauges are the same! I went and got a used cluster for mine from Pull-a-part for $20.00 with a tach. I ended up only using the fuel gauge out of the pull-a-part unit due to some reason with the tach acting funny when I installed it in my rig. :shrug

 

[Maxson]

:smilie_slap

Me and my 6 posts seem to have fat-fingered the thread subject... my truck is an 87.... I knew I wasn't reading your replies wrong, lol... sorry for that!

I have been tinkering on and off all day between the forums and the garage... Before I drop the tank tomorrow, I have two more items...

As I could not find my multimeter today (just moved :banghead) I was poking around with my test light and wanted to verify if the results are in line with the sender prognosis... I have a complete circuit between ground and the Y/Wh at the connector in the engine compartment - test light goes on, however weak. The Y/Wh comes out the other end DB/Y and the power continues through that connector and through the firewall and all the way up the to the cluster... This seems inconsistent with what I have been reading that a pegged FULL gauge = bad connecting/break/fault in the Y/Wh.

Also, I noticed that when I turn on the ignition, the needle does move slightly more from the pegged full position towards FULL (or in this case so far right it should say OVERFLOWING).

I know this has been done to death around here, and the newbie fuel gauge thing is cliche, but at this point, I have read so much on this I think I may have confused myself even further :doh0715:

I am going to borrow my brother-in-law's tester tomorrow and will test the sender resistance anyways, but I may not sleep tonight if I keep wondering about the above.........

Cheers,

Maxson

 

[Maxson]

I have had you diagram out all day :thumbup

My confusion is that I have been reading that the pegged FULL is a result of an open circuit/bad or broken connection on the Y/Wh wire.

Mine is pegged FULL and the wire/connections seem to be fine.... Reading power all the way to the cluster

 

[Maxson]

Et Voila! :beer

I will get dirty tomorrow and post results!

Thanks!!!!!

 

[Maxson]

Tomorrow... an month from now.... eh.

I am finally getting around to fixing this now that the baby has come and I have some time off work, and I have another question.

Do I need to replace the whole in-tank pump assembly if the sender is bad? This morning I checked resistance between the pin on the sender for the Y/Wh wire & the pin for the Bk wire and there was no reading (or meter change) at all. I know that Steve shows a PN for the level sender on his supermotors EFI Fuel Pump writeup (http://www.supermotors.net/vehicles/registry/media/72016). Will this part work on my '87? If it does, should I only have to procure it, the lock ring and the seal from my local dealer? What is the average rainfall of the Amazon Basin?

UPDATE: My local kragen carries the sending switch, but not for the 87. The part they list is 90-96. Is this part interchangeable for my 87?? Am I barking up the wrong tree? Any advice appreciated here!

 

[Maxson]

Have you looked thru the Fuel Pump Access album? :deal

http://fullsizebronco.com/forum/showpost.php?p=1804550&postcount=25



So, can you expand a bit on your opinion that the whole assembly would probably have to be replaced? (Although my ZERO experience counts for squat) It would make sense that if a replacement sending switch is available (and $100 less than the whole potato) that would be the way to go. I am would like to know why you think "probably", as it makes ME think that I am missing or overlooking something......

 

[Maxson]

Haha, that makes perfect sense. Thanks...

 

[petlover07]

Mine is backwards, and shows full until you get down to about a gallon, then goes down to empty in a few days. (or shows Empty until about a gallon, then goes up to Full):doh0715:

I am guessing it is crossed wires somewhere along the line.

When I got it, I thought it had a full tank...I was stoked!!!! :shocked

 

[Maxson]

As promised (though a little late :brownbag) the pump and sender were replaced last night by the sweet glow of flashlight, and everything is working perfectly.

Never thought a moving needle could make me so happy.....