Engine/Transmission (1998.5 - 2002) Fuel Guage inaccuracy

[Hill Country Ram]

My 2001 4X4's fuel guage reads empty at 25 gallons and I know my truck has a 35 gallon tank. Is there a way to fix this or do I just have to live with it?

The truck is a 2001 4X4 6 speed, w/ just over 40,000 miles.



Thanks- Gary Mc

Spring Branch, TX

 

[duaneparks]

Mine does the same thing. However, the way that diesel likes to foam, I usually use the indicated "empty" as a refueling point as opposed to seeing how far I can go on a tank (which I can extrapolate anyway).



Heck, my family doesn't last a whole tank on a trip anyway without needing to stop somewhere.



Duane

 

[TowPro]

THey all do this, at least until your gauge dies, then it will show fuel and you will run out!



Anyway the manual says the check fuel light will come on when you have around 7 gallons left.

 

[Wheaties]

No, not all of them do this. . It sounds like you have a bad sending unit, a component that has been known to fail. They aren't very well made.



Matt

 

[emjay]

The owners manual states the the trip computer is based on a 30 gallon tank, even though the truck has a 35 gallon tank. I wonder if the sensor is too -- my low fuel lamp comes on when there's about ten gallons -- nearly a third of a tank of fuel left. The gauge reads 1/8 tank at that point. When the trip computer reads zero miles until empty, there is 5 gal left in the tank, and the needle on the gauge is aligned perfectly with the E tick mark.



No fuel gauge (that I've ever seen) is very accurate. Thats why they read E and F rather than some actual quantity (i. e. gallons). Whatever it reads, it will be consistent unless its broken, so all you really have to know is how much fuel is in the tank at a particular gauge indication. My preference is to run mine all the way down to E, I know there's plenty of fuel left at that point. I can easily go 30 miles from that point whether I'm towing or not.

 

[Wheaties]

Right you are Mike, but no fuel gauge should read empty when it is 25/35 = . 71 full 7/10's should

read about 7/10's... maybe compensating for usable fuel 30 out of 35 gallons?????



Something is broken here, I'm guessing it's the sender.

 

[RBSOB]

Hey Wheaties!

I think the original post meant 25/35 GONE and gauge reads empty. In other words "E" with 10 gal. remaining. I THINK? Not unheard of. My light comes on with 8 gal remaining, hits flat- out "E" with 2 gal. remaining... . it was not comfortable finding this fact out . Jim G. ... working on getting to 8\23 meet

 

[jboehm]

Mine's working well. . know when the "dinger" comes on, that I can put about 28 gallons in. Never failed yet, but, I do notice that the gauge goes down faster after a half tank... just gotta keep it up there and check the mileage... The mileage is my best guage. . even towing. I know I have about 8 gallons, or less than a 100 miles to drive before I need to seriously fillup. Figger I can find fuel in that time. .

 

[Hill Country Ram]

When the low fuel light comes lights up and chimes I can squeeze 21 gallons into the tank. When the guage reads empty 25 gallons is all that will go in. I'll give the a dealer a shout about a new sending unit.

Any dealer rec's for the San Antonio/Boerne area?



Thanks- Gary Mc

 

[emjay]

You'd think they (DC) would've paid a bit more attention to the accuracy of the fuel gauge on a diesel.

 

[Jumbo Jet]

I had a 2001 and now have a 2002.



The 2001 gauge performed exactly like the 2002 does.



When the chime goes off, I have 10 gallons left.



I set the trip meter to 0 and know that I can go at least 150 miles while empty and 100 miles when towing.



Most I ever squeezed in the tank using this tactic is 32. 5 gallons. And that was about three weeks ago when I ran the truck for over a week after the chime went off.



I don't think anything is broken, that's just the way it is designed.



Works for me!

 

[DarrellB]

Hey that sounds familiar

When the fuel light comes on I can put 20 gallons in, when the fuel gauge reads almost empty I can put 25 gallons in. The most I've ever added was 30 gallons on a trip up North. I was sooooooooo happy to see the Pilot Station I almost cried.



Darrell

 

[Smills]

My gauge got funny on me the other day and I almost ran out put 34. 5 gal in the truck was real close it sputtered when I stopped. Thats to close for me the gauge wasnt even all the way on E and usually I take it to the bottom and still have 4 gal.

 

[Oxjockey]

I had my first chime & light last night. I actually didn't realize what the chime was until I looked down, it came on at 1/8 tank left. I got all the way home (about 30 miles) and proceeded to fill up and it only took 24 gallons. Ugh. I guess it's better that way then coming up short.



Bryan

 

[AlFischer]

My gauge and computer are also VERY inaccurate. Had an old Caddy that had a computer and it was accurate to within 0. 1 mpg and less than 1/2 gal of fuel. The Dodge computer is frequently off by 1. 0 mpg and my guess is 5 gal of fuel. Very poor.



Question is if it is fixable or 'just that way'?

 

[Steve Campbell]

Jumbo Jet said

"I don't think anything is broken, that's just the way it is designed. "



I agree that it was designed that way. But I believe it was done to "cover up" a faulty lift pump placement. I have a fuel pressure guage and the fuel pressure is 1 lb less at "E" than at "F" on the guage. There has been enough speculated on the forum about lift pumps, that it is generally accepted (IMO) that the lift pump will last longer if you run on the top half of the tank.



Sorry about being so far off of the topic, but there is a concern here in my opinion.

 

[Ladders]

Also,

if the VP44 is "cooled" by fuel, then you need more than 1-2 gals to be recirculated. The fuel would not get cooled enuff with so little in the tank. If you have pulled the sender out (I have) the "bucket" holds about 1 gal at the pic-up end. We "older" timers discussed (cussed?) this and the general concensus was that DC designed it for about 3-5 gals on E for a safety margin to prevent problems. If you have ever run-out (have) and tried to restart after getting refueled, its worse then changing fuel filter and having restart problem(s) (we know how that is - read about in the TDR). If I recall, consensus was that you COULD lose both the lift and VP trying to get it re-running (not including the filter and other "bottom drain" particles that would/could plug everything up gud and tight (injectors, lines, etc). DC did us a favor by trying to get us to re-fuel with some left (ever had a Big Rig run out?? big $$ to get a re-start). So, we that know better, run a little "closer" to the edge but can appreciate the extra safety margin... ... have "pushed" it to the limit a few times but the only time it did run-out was when the fuel guage said 3/4 left (should have known you cant drive 600 miles on a 1/4 tank ).





SOTSU!!

\\BF//

 

[Mschevey]

I agree I had some in-depth conversations with tech's and inside people. They have the 'E' point set with the cooling of the VP-44 in mind. If you figure on almost the worst possible case (outside air temp ~110 deg F), with the truck under heavy load, (less volume returned to tank), etc. Then you need at least 5 gal. in the tank to insure that there is enough cooling available for the vp-44.



The fact it gives us a security factor for running out is only a byproduct. Also keep this in mind if towing across a desert.



Mike Schevey

 

[Wheaties]

Re: Hey Wheaties!

Originally posted by RBSOB

I think the original post meant 25/35 GONE and gauge reads empty. In other words "E" with 10 gal. remaining. I THINK? Not unheard of. My light comes on with 8 gal remaining, hits flat- out "E" with 2 gal. remaining... . it was not comfortable finding this fact out . Jim G. ... working on getting to 8\23 meet

I stand corrected. Hill Country Ram posted a follow up confirming this. If he had 25gallons in his tank and it said empty, I'd say there was a problem. If he can put 25 gallons in when it says empty, I'd agree that it just isn't all that accurate. Plus his original post says he knows he has a 35 gallon tank, right?



Well, if they were supposed to give you a 35 gallon tank and put in a 30 gallon tank instead, it wouldn't be the first time. Can you confirm for sure that it is a 35 gallon tank, or is that just what you paid for ?



Even so, fuel gauges are notoriously inaccurate in lots and lots of places. Standard procedure for aircraft pilots is to stick the tanks to estimate fuel, never rely on fuel gauges, and only take what fuel gauges say 'under advisement'



You all have made some interesting points as to why you might not want your fuel tank to get that low. No one has mentioned that a low tank invites condensation to form, and can lead to bugs growing in your tank. Ask Steve StL. , it happened to him, and he went through half a dozen filters in the process of cleaning them out!!!

 

[Hill Country Ram]

I paid for a 35 gallon tank, I better have gotten one!



Does anyone have measurements for what they know is a 35 gallon fuel tank? If so I'll go out and measure mine.



-Gary Mc