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How do I adjust the fuel gauge and/or the fuel sending unit?
I recently purchased a 2008 F250 Gasser. She's a Super Cab long bed with 158 inch wheelbase (verified). My best research indicates she should have a 38 gallon fuel tank. But, at about 250 miles, the gauge says she's almost empty. She's getting 11 MPG highway. I decided to simply run her out of fuel and see how much gasoline I can actually put in. Yes, I have ten gallons of gasoline with me. So far, I have over 400 miles since my last fill-up. Gauge and digital display claim she ran out of gas 100 miles back.
So, I need to adjust something so that the gauge is closer to accurate. Does anybody know how to do this?
Could be your sending unit has some fouling on the contacts causing your gauge to not read correctly, I suggest running a bottle of Sea Form or Techron through it every time you fill up, over time it might clean off the contacts and get your gauge reading correctly. There’s no adjustment on them that I know of.
Had this issue way back on my 99, batteries died when out of town for a couple weeks, put new batts in, didn't think much about it, noticed after that my fuel gauge was off also, so I filled up fuel tank all the way, parked it on a flat level surface, unhooked batteries for about 30 mins, hooked them back up and fuel gauge was back in accuracy range...
Might try that and see what you get...
Everybody raves about seafoam so I took a few jets from a carb I was going thru and soaked them in straight SF. It did nothing for them. I say its snake oil like most of the stuff you buy these days. Far as the gauge being off it might be a case of a replaced fuel pump, and like many or most these days from china they are less than stellar in the tank reading department. Been there, done that.
Everybody raves about seafoam so I took a few jets from a carb I was going thru and soaked them in straight SF. It did nothing for them. I say its snake oil like most of the stuff you buy these days. Far as the gauge being off it might be a case of a replaced fuel pump, and like many or most these days from china they are less than stellar in the tank reading department. Been there, done that.
Everyone's entitled to their opinions, in my experience, I have used sf in quite a few things with great results, had my neighbors quad was running terrible, put half a can in it and left it idling in my garage, came out about 20-30 mins later and it was purring, same thing with a work sxs, had been sitting for a while, long while, put fresh fuel in, added a can and drove it around the property, within 20-30 mins was running way better. SF isn't meant to be a parts cleaning solution, it's an additive, so using it as a parts cleaner, I would not expect good results IMO.
To the OP, have you tried fueling it up completely and disco'ing batteries for 20-30 mins? I'd put $20 that'll work
The fuel gauge sending unit is a variable resistor that changes value as a wiper moves across it with the gas level. My 97econline had a wear spot on the resistor where the wiper rode most of the time...just below the 1/2 tank mark. This wear sport caused erratic resistance readings and explained why my gas gauge would not move reliably until the wiper was off this bad section of the resistor. You can measure the (almost) empty and full resistance values and compare to the specs on a new one. If the resistance is OK you will have to troubleshoot the corresponding voltage going into the ECU.
Everybody raves about seafoam so I took a few jets from a carb I was going thru and soaked them in straight SF. It did nothing for them. I say its snake oil like most of the stuff you buy these days. Far as the gauge being off it might be a case of a replaced fuel pump, and like many or most these days from china they are less than stellar in the tank reading department. Been there, done that.
This isn't a debate about Sea Foam or any of the other can of snake oil. It's about how to resolve my issue with the fuel gauge reading. Hopefully I will get it sorted, with the help of others, and, the next guy / gal with this issue will have some direction for their issue.
No, I have not done anything as of yet. Between the snow and wind chill, it's about 10 degrees currently with wind chill, the truck can sit a few more days. But yes, my plan is to buy some Sea Foam and use it as described on the can. If that means I need two cans then that's what it will be. Yes, I will fill the tank and do a battery disconnect.
Yes, the fuel pump could have been replaced with a cheap Chinese part. That could be the problem. I have way too much experience with cheap Chinese parts that barely last long enough to go around the block. Those stories would make for a good thread in itself.
If, it comes down to it, is the variable resistor adjustable? Clearly the Sea Foam is used to clean the contacts on this variable resistor. I'm not going to replace the fuel pump unless I have a fuel delivery issue.
Here the the level sensor from my van. You can see the extra wear 1/2 tank to empty. When looking for a new fuel pump I did not see this part as stand alone option. If you are going through the trouble of pulling the pump, you should replace the entire assembly. But you have to search to find a high quality pump assembly if your is out of stock at Ford.
I get the snow and wind chill, grew up in MO, did Cold Weather Training in WI, now in my advanced age of 55 I Operate a Sno-cat 6 mos+ out of the year and I find I'm not as near tolerant to the cold as I was when a kid! Just went out earlier to hook up Cat to my truck for this week and man, I got cold!
Originally Posted by Racer Z
This isn't a debate about Sea Foam or any of the other can of snake oil. It's about how to resolve my issue with the fuel gauge reading. Hopefully I will get it sorted, with the help of others, and, the next guy / gal with this issue will have some direction for their issue.
No, I have not done anything as of yet. Between the snow and wind chill, it's about 10 degrees currently with wind chill, the truck can sit a few more days. But yes, my plan is to buy some Sea Foam and use it as described on the can. If that means I need two cans then that's what it will be. Yes, I will fill the tank and do a battery disconnect.
Yes, the fuel pump could have been replaced with a cheap Chinese part. That could be the problem. I have way too much experience with cheap Chinese parts that barely last long enough to go around the block. Those stories would make for a good thread in itself.
If, it comes down to it, is the variable resistor adjustable? Clearly the Sea Foam is used to clean the contacts on this variable resistor. I'm not going to replace the fuel pump unless I have a fuel delivery issue.
There is one other possibility I’d like to put out there as you don’t know the full history of the truck, if someone swapped out the cluster or went in and changed the fuel tank size to a 30 or 19 gallon tank, this could be your problem.
As for a bad sending unit, the cluster would throw a code for that, a standard obd2 reader won’t show you it as it’s not emissions related/pcm, I would get forscan and the recommended adapter and check your truck over with that, you can also check fuel tank size and change it with forscan.
"This isn't a debate about Sea Foam or any of the other can of snake oil. It's about how to resolve my issue with the fuel gauge reading. Hopefully I will get it sorted, with the help of others, and, the next guy / gal with this issue will have some direction for their issue."
True, my point was why waste $12 on a can of snake oil that will do nothing for worn or cheap parts. As mentioned, to each his own. Good luck with your fix. Sounds like my 99's gauge but it did have a new pump put in it. 15 miles home from the station it typically is down to 3/4 of a tank. 250 miles and its on 1/8 of a tank with the 29? gal tank. . I average 13mph typically.
I agree that a can of snake oil does not include a new sending unit. If the contacts are simply gummed-up, and snake oil softens the gum, it's an easy fix. Much easier than dropping the tank and pulling the fuel pump. I'm willing to toss $12 before pulling the sending unit. I can, and have, used the trip-meter to estimate the fuel in the tank.
Yesterday, I finally ran out of gas, 430 miles from last fill-up. Dumped in five gallons that I had with me and motored two miles to the gas station and filled up. In total, 38 gallons.
I had some SeaFoam with me, enough for 44 gallons, so I dumped that in during fuel fill. I had read the info on all the SeaFoam type products at the parts store. Most didn't say much at all. SeaFoam had the most info, but they all seemed about the same. The most consistent was to use one once per one gallon. You can use more if you think the 'gum' build-up is sever.
Today I disconnected the battery for 30 minutes, or more.
Now it's a matter of time before I can see any results.
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