Replace the fuel sending unit or just the float?
06-12-2011, 12:34 PM
#1
Member
Thread Starter
Replace the fuel sending unit or just the float?
'85 short bed, granny tranny, side fuel tank only, 4.9L.
I bought this truck 4 or 5 years ago with this problem - previous owner told me about it, no biggie, and it hasn't changed: When full, gage reads full, but when it drops, it drops fairly quickly, and when it is on E, there is still about 70 miles (I figure about 6 gallons) worth of fuel left.
Gage otherwise operates normally - totally smooth, no jumping, etc. With full tank, reads "Full" for a while, comes down fairly rapidly to "E" (at 12-13 mpg, what the hey!), but still has quite a bit of fuel (and over 70 miles of driving range) left at that point.
I was going to replace the sender (LMC Truck) at around $70, but I see that they have the floats for $6.
Since $6 sounds a lot better than $70, I am wondering if a new float will fix it. The only thing about that is that I would expect a defective float to never get the gage to "Full" - *unless* when things are working correctly, the fuel gage stays on full a l-o-n-g time before it starts dropping, and maybe that is the case (maybe someone could verify that?).
So - my question is: With what I've described, would a leaky float explain the symptoms I'm having and still it be reasonable that the gage would read "Full" when the tank is full?
If so, I'm willing to replace just the float (would also replace the sender-to-tank o-ring) and take the risk that a year from now, the sender that may be operating fine now could crap out. I just want to know if you think replacing the float could correct the present condition.
Thanks mucho!
I bought this truck 4 or 5 years ago with this problem - previous owner told me about it, no biggie, and it hasn't changed: When full, gage reads full, but when it drops, it drops fairly quickly, and when it is on E, there is still about 70 miles (I figure about 6 gallons) worth of fuel left.
Gage otherwise operates normally - totally smooth, no jumping, etc. With full tank, reads "Full" for a while, comes down fairly rapidly to "E" (at 12-13 mpg, what the hey!), but still has quite a bit of fuel (and over 70 miles of driving range) left at that point.
I was going to replace the sender (LMC Truck) at around $70, but I see that they have the floats for $6.
Since $6 sounds a lot better than $70, I am wondering if a new float will fix it. The only thing about that is that I would expect a defective float to never get the gage to "Full" - *unless* when things are working correctly, the fuel gage stays on full a l-o-n-g time before it starts dropping, and maybe that is the case (maybe someone could verify that?).
So - my question is: With what I've described, would a leaky float explain the symptoms I'm having and still it be reasonable that the gage would read "Full" when the tank is full?
If so, I'm willing to replace just the float (would also replace the sender-to-tank o-ring) and take the risk that a year from now, the sender that may be operating fine now could crap out. I just want to know if you think replacing the float could correct the present condition.
Thanks mucho!
Last edited by Peva; 06-12-2011 at 12:39 PM.
06-12-2011, 09:11 PM
#2
Senior Member
I think you just described every car I have ever owned. Most fuel gauges are not linear. Some worse than others.
I would expect a saturated float to... not float... and never read full and read empty most of the time, or waffle around alot.
A sticky float arm may hang up at full and fall down after being jarred around.
If I were going to go to the trouble to replace the float then I would do the whole sender. On my '86 the sender was really gunked up with tar like deposits. Too much trouble and risk messing up or bending the wiper/ contact. It could get worse or not work at all after messing around with it.
If your old sender looks OK and the float is not leaky then I would not expect a new sender and/or float to operate much different than what you have been experiencing.
I got my tank & sender at Autozone. Probably quite a bit cheaper than LMC. Special orders are overnighted to the store at no extra cost.
So shop around.
I would expect a saturated float to... not float... and never read full and read empty most of the time, or waffle around alot.
A sticky float arm may hang up at full and fall down after being jarred around.
If I were going to go to the trouble to replace the float then I would do the whole sender. On my '86 the sender was really gunked up with tar like deposits. Too much trouble and risk messing up or bending the wiper/ contact. It could get worse or not work at all after messing around with it.
If your old sender looks OK and the float is not leaky then I would not expect a new sender and/or float to operate much different than what you have been experiencing.
I got my tank & sender at Autozone. Probably quite a bit cheaper than LMC. Special orders are overnighted to the store at no extra cost.
So shop around.
06-15-2011, 12:53 PM
#3
Member
Thread Starter
Hah!
Thanks for the info.
I just wouldn't have expected 6+ gals. to be in the tank at 'E'. I remember fuel gages on vehicles years ago being pretty sloppy, but I didn't remember them being that bad - maybe so.
"If I were going to go to the trouble to replace the float then I would do the whole sender" - yeah - I hear you. I'm always trying to save a buck. But you're right - that can backfire on you. The time dealing with it is important too. LMC only allows returns for defective or wrong parts shipped. If they allowed returns for any reason, even if there was a re-stocking charge, I'd order the float *and* the complete sender, and if it turned out the the float was in fact the problem, return the unopened sender for partial refund. Either way, I'd only be out the cost of the unused float or the un-refunded part of the returned sender.
Didn't Elvis sing a song by that name? "Return the Sender" (j/k) Oh great - now that will be in my head all day!
At your suggestion, I just checked Autozone, and the only fuel llevel sender I see is one for an aftermarket gage. Did they have an OEM replacement sender that you got?
Thanks for the info.
I just wouldn't have expected 6+ gals. to be in the tank at 'E'. I remember fuel gages on vehicles years ago being pretty sloppy, but I didn't remember them being that bad - maybe so.
"If I were going to go to the trouble to replace the float then I would do the whole sender" - yeah - I hear you. I'm always trying to save a buck. But you're right - that can backfire on you. The time dealing with it is important too. LMC only allows returns for defective or wrong parts shipped. If they allowed returns for any reason, even if there was a re-stocking charge, I'd order the float *and* the complete sender, and if it turned out the the float was in fact the problem, return the unopened sender for partial refund. Either way, I'd only be out the cost of the unused float or the un-refunded part of the returned sender.
Didn't Elvis sing a song by that name? "Return the Sender" (j/k) Oh great - now that will be in my head all day!
At your suggestion, I just checked Autozone, and the only fuel llevel sender I see is one for an aftermarket gage. Did they have an OEM replacement sender that you got?
Last edited by Peva; 06-15-2011 at 12:55 PM.
06-16-2011, 04:48 AM
#4
Senior Member
I learned years ago to judge fuel quantity by the odometer. Ford fuel gauges suck at best. I say Ford gauges, only because I have never owned anything else to compare too. I figure X miles for city driving and X+ for highway driving. Just finished a 2800 mile road trip with my wifes 96 Explorer, gauge on empty and low fuel light on, 17.9 gallons filled it up. That meant I had 4 gallons in reserve or 60 more miles. EEEEKKK, some of those towns were more the 60 miles apart. Reset the odometer at fill up and go from there, keep your money in your wallet and learn a better alternative to a common problem.
06-16-2011, 08:52 PM
#5
Member
Thread Starter
...gauge on empty and low fuel light on, 17.9 gallons filled it up. That meant I had 4 gallons in reserve or 60 more miles. EEEEKKK, some of those towns were more the 60 miles apart. Reset the odometer at fill up and go from there, keep your money in your wallet and learn a better alternative to a common problem.
06-17-2011, 02:02 AM
#6
Senior Member
Hah!
Thanks for the info.
I just wouldn't have expected 6+ gals. to be in the tank at 'E'. I remember fuel gages on vehicles years ago being pretty sloppy, but I didn't remember them being that bad - maybe so.
"If I were going to go to the trouble to replace the float then I would do the whole sender" - yeah - I hear you. I'm always trying to save a buck. But you're right - that can backfire on you. The time dealing with it is important too. LMC only allows returns for defective or wrong parts shipped. If they allowed returns for any reason, even if there was a re-stocking charge, I'd order the float *and* the complete sender, and if it turned out the the float was in fact the problem, return the unopened sender for partial refund. Either way, I'd only be out the cost of the unused float or the un-refunded part of the returned sender.
Didn't Elvis sing a song by that name? "Return the Sender" (j/k) Oh great - now that will be in my head all day!
At your suggestion, I just checked Autozone, and the only fuel llevel sender I see is one for an aftermarket gage. Did they have an OEM replacement sender that you got?
Thanks for the info.
I just wouldn't have expected 6+ gals. to be in the tank at 'E'. I remember fuel gages on vehicles years ago being pretty sloppy, but I didn't remember them being that bad - maybe so.
"If I were going to go to the trouble to replace the float then I would do the whole sender" - yeah - I hear you. I'm always trying to save a buck. But you're right - that can backfire on you. The time dealing with it is important too. LMC only allows returns for defective or wrong parts shipped. If they allowed returns for any reason, even if there was a re-stocking charge, I'd order the float *and* the complete sender, and if it turned out the the float was in fact the problem, return the unopened sender for partial refund. Either way, I'd only be out the cost of the unused float or the un-refunded part of the returned sender.
Didn't Elvis sing a song by that name? "Return the Sender" (j/k) Oh great - now that will be in my head all day!
At your suggestion, I just checked Autozone, and the only fuel llevel sender I see is one for an aftermarket gage. Did they have an OEM replacement sender that you got?
After setting up all the parameters for the current vehicle then search [sending] not sender. If you have the in tank pump mounted on the sending unit then search [fuel pump].
Well I just put in your parameters 85 4.9L 6 cyl and no sending unit came up. I have the 86 5.0 with EFI.
Try Bronco Graveyard: http://broncograveyard.com/
06-17-2011, 08:37 AM
#7
Senior Member
Hey Peva, thanks for the heads-up about the unuseable fuel, forgot about that. I should have said reset the trip odometer, you know the button on the dash. Just realized another error, this message is in the clasic corner, they didn't have trip reset did they? Boy am I getting older.
Last edited by Good old Bill; 06-17-2011 at 08:39 AM.