Fuel gauge on FEH inaccurate
 

I'm new to the forum. I have a '07 FEH which is about a month old. I'm quite pleased with the vehicle. I'm getting about 32 MPG and have about 1500 miles so far. One thing is bothering me though, when I fill up (the fuel guage reads E and the low fuel alarm is on as well) I can only get about 12 gallons in the tank. The owners manual says that it has a 15 gallon tank. Does any one else have this problem? I thought maybe it was a break in sort of thing but I just filled the tank for the 5 time today and only put in 11.6 gallons. I have thought about carrying a gas can and driving till I run out but haven't done it yet.

The information I have read at this forum has been very informative and has helped me to get the most out my FEH. Thanks!

Re: Fuel gauge on FEH inaccurate
 

What does your Miles To Empty gauge say? At 32mpg it shoud be reading aprox 480 miles at at tank top off.

Re: Fuel gauge on FEH inaccurate
 

Your vehicle isn't unique but yours seems a little worse than both of mine.

If I drive mine to 50 miles to empty I usually take around 13 gallons or so. At 0 MTE it takes right at 14 gallons.

I have gotten to where I don't even look at the fuel gauge. I either look at the trip odometer or the miles to empty gauge to know when to fill up.

The gauge is only accurate at full and empty. Everything in between is non-linear and seemingly arbitrary.

Re: Fuel gauge on FEH inaccurate
 

I'll have to check what MTE says at full but it only shows 10 or 20 miles when the guage it indicates empty. I think the low fuel alarm goes off at an MTE of about 60.

I don't really care much about any indication but full or empty. I intend on getting a Scangauge, but I would like for the MTE for the two devices to sort of match.

Re: Fuel gauge on FEH inaccurate
 

LOL, I even mention that in the FAQ.

On my last tank, I was at 3/4 after having driven about 60 miles, yet I was at 1/8 of a tank, and still had 120 miles to empty on my display.

Also, you get more than one (or at least on the older models) low fuel warning, you should get them at 50, 25, and 0 MTE. You can press set to clear the low fuel warning.

In addition, keep in mind that your FEH is brand new, so until you hit some of the break ins, you're not going to be at a fantastic performance rate, which means a slightly reduced range. While it's common for me now to get around 500 miles on 13 gallons of gas, I wasn't when I first got her; generally I fill up with 5-15 MTE.

Re: Fuel gauge on FEH inaccurate
 

I believe this is pretty standard practice among most cars. Lots of cars intentionally misreport their "empty" status to avoid people running out of gas. All cars I've driven in the past have fit this behavior (Volvo, Chrysler). On all of them the fuel guage won't report about 2 gallons.

I've confirmed this on my FEH by driving until "miles to empty" hits 0 (and even past that) and then fueling up ~13 gallons to "full".

So it's a good thing for most people to have this "feature".

Re: Fuel gauge on FEH inaccurate
 

My Jeep Wrangler would run out of gas with the gauge showing 1/8 of a tank. :(

Re: Fuel gauge on FEH inaccurate
 

My experience is like Ray's in that it seems predictable at fill-up and empty, and unpredictable in between. Right now I am getting around 41 mpg (computed) and when I fill-up, it's estimating a little over 600 MTE (41 mpg X 15 gal =~ 610 MTE) while at fill-up its 41 mpg x 13.5 gal to fill-up =~550 MTE. Not really sure what values it actually uses, but I am consistent in predicting what the FEH is going to read using the current mpgs and these estimates.

Re: Fuel gauge on FEH inaccurate
 

My God Chuck, a 41mpg tank in an AWD FEH???? That's just great and proves that the AWD can use the same bag of tricks I use in my FWD to punch out those big numbers.

Anyway, the fuel tank volume has been an issue since day one. I've drain her dry and keep an eye on how much gas I had left after 0 MTE. It's about 1.3 gallons. The size of the tank is said to be 15 gallons, but you can put up to 17 gallons in it.

A fuel tank mounted fuel vapor vent valve and vapor control valve prevent fuel tank overfilling during refueling. They keep liquid fuel from entering the EVAP canister even during rollover ('05 PCM/ED manual page 1-101). My guess is that this is why you can put more fuel in the tank sometimes, and less other times. This is the reason I go by the SG for MPG. It seems to be the best I've found. I've narrow down the Nav Sys to 10 hours of data before it drops old data, but it's still better than basing your mileage on fill up gallons.

GaryG

Re: Fuel gauge on FEH inaccurate
 

Gary:

Thanks for the nice thought, but my wife now drives the AWD and I now have a FWD.

Re: Fuel gauge on FEH inaccurate
 

I usually fill up between 50 MTE and 20 MTE. I've never squeezed more than 13.4 gallons in at that point.

Also, can anyone clarify how and when the vehicle determines MTE? Mine seems to vary radically. It seems to re-calc every time I start the vehicle, but sometimes it changes ALOT. I started it today at an avg of 32.4 mpg and it reported like 414 MTE. Then shortly thereafter I started it again at 32.0 mpg and it reported 361 MTE. I had only driven about a mile between these two stops. Wacky.

Re: Fuel gauge on FEH inaccurate
 

Chuck, the FWD can get extreme mileage when broke in, but I'm not seeing it with any other posters. I went to check todays SG reading and this is the results.

Today was 48.0 mpg
26mpg average
2.9 Hr
4157 rpm max
77.6 miles
1.6 gallons used

This was with the A/C on from a cold start. I had to use the Ice for cooling alot to stay cool.

garyG

Re: Fuel gauge on FEH inaccurate
 

Oh really???
:P

Re: Fuel gauge on FEH inaccurate
 

Yea, it is. In 1972 I bought a brand new SuperBeetle. That car had by far the most accurate fuel gauge I have ever seen. I was on the first tank of gas & it was still reading a very tiny sliver above empty. I should have stopped for gas on the way home from work, but I was tired & just wanted to get home so I skipped it.

That gas got very good gas mileage, so I figured I could make it to work the next morning with no problem. I pulled out the next morning & as I was driving away, the needle edged to the empty line. The car died totally one block later just as I left the light right in the middle of a VERY busy intersection............

~John

Re: Fuel gauge on FEH inaccurate
 

Sorry John

When I looked back at my post, I did type "any other posters", but it was a typing mistake. I meant "many other posters". I also put "26mpg average" and meant "26mph" average.

Just looked at the mileage data base to see how many I affended and see you have a 37.3mpg average. Are you not maintaining at least a 42mpg average overall? Also, it looks like two other people are reporting over 39mpg averages. I'd like to hear from them if they can hit extreme numbers like we report.

Wayne has wanted me to post my tanks for some time now, so I guess I'll start doing it. The SG really helps with tank averages now. Among other things, I just didn't think messing with gallons pumped was worth my time in the past. One problem I saw when I found out about the data base was I had about 6,000 miles on My FEH with no records. Will it be unfair to start reporting after 27,000 miles, when most included break in mileage in their average?

Any thoughts?

GaryG

Re: Fuel gauge on FEH inaccurate
 

Re: Fuel gauge on FEH inaccurate
 

John

When I first got my FEH in Feb '05, it was nice and cool, so A/C was not required. Driving low speeds along the coast put me in the 36-41mpg tank average. The subject of this thread is the fuel gauge, but you and I know, it's the inaccurate tank fills that is the real problem. It may have been when I filled up, that I could not get the amount of fuel in the tank that I burned on that tank of gas. Same thing with when I filled up later, I was able to put two extra gallons in, and brought my millage way down for that tank.

Their were only two tank readings during the summer of '05 that I got 29 and 31mpg. At that time, I estimated my overall lifetime mileage at ~38mpg for the first six months of ownership. My wife was driving the FEH more at that time also.

From Sep. '05 till this date, I don't recall any tank below 40mpg, with most tanks being between 44 and 47mpg. I did get a ~55mpg (~300miles) tank, but it was not a full tank burn. Ive had a few tanks in the 52mpg range.

To date, I would estimate my lifetime average at ~43mpg. Starting this fall when thing cool down, I expect my tanks to be between 47-52mpg most of the time. My lifetime average should go up with all things considered also. If I started the fuel data log now, it may cause others to look bad and give up I guess. Maybe the MTE picture on my sig page should be the goal to hit and exceed.

E-10 drops my mileage 5mpg because I can't adjust to it like those that drive with it all the time. Also, "Keep Alive Memory" (KAM) adjust the "Fuel Trim" and oxygen sensors with fuel quality (% alcohol or oxygenates). This seems to effect my mileage after the ethanol is gone. This keeps the ICE running rich for awhile on pure regular gas. Drafting can readjust the KAM as RPM's reduce with speed and load, but the adjustments need to be made throughout the KAM table of engine speed and load.

If your using E-10 all the time, your KAM and fuel trim are stable most likely. Your driving style has adjusted with this stable fuel trim, so I wouldn't know what your reduced mileage could be.

GaryG

Re: Fuel gauge on FEH inaccurate
 

How about this idea...

In order not to taint the main database, how about both of us keep a running total starting from NOW in our signature line? Each new tank, just change the signature line.

Example: "Starting at 25,000 miles, I've been getting 42.4 MPG over the past 3 tanks and 1255 miles."

Next time change to: "Starting at 25,000 miles, I've been getting xx.x MPG over the past 4 tanks and xxxx miles."

Whacha think?
-John

Re: Fuel gauge on FEH inaccurate
 

I have heard that cars actually use the gas to keep the pumps cool. So that amount under E might not just be for emergencies but be sure there's gas left to cool the pumps. I know a few people that won't let their cars get much below 1/4 tank. They say then the pump might suck up debris at the bottom. Personally, I wait until I get the low fuel warning which means there's at least 4 gals left.