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FrayAdjacent · 10-28-2008, 10:43 AM

I think I'm having more issues than just a hinkey fuel gauge...

I fill up the car every time at the pump. Meaning, I let the pump run until it stops. I do not try to squeeze in more fuel after that point, because my experience is that when the pump stops, the tank is FULL. It will overflow a little if I try to squeeze more fuel in.

A few weeks ago, I 'topped off' from a little above 3/4 tank because I was running down to Houston, and wanted to have as much fuel as I could before I left. I think the pump cut off before the tank was full, since I was expecting to put in about 2-3 gallons, and only got 1.5 or so in (iirc). I also record my fuel consumption and calculate fuel economy - and that 'tank' came out to 33mpg! I thought it may be an anomaly with the pump and went about my life.

After that fillup, I have noticed that when I fill up, the fuel gauge needle is never on top of or over the dash for Full. It's always a bit below.

Yesterday, the low fuel light came on a few miles from home. I had about 220 miles on the trip gauge (which I reset every fillup). I figured this is probably a symptom of the fuel gauge calibration issue I'm seeing. Today on the way to work, I filled up with 230 miles on the trip gauge, and put in 13.47 gallons. That comes out to a fuel economy of 17mpg!! The car's MPG gauge is showing me 26.2, which is slightly higher than the average I usually calculate. I should be hitting 24-25.

So I'm thinking something is wonky with the tank or evaporation system causing my fillups to be inconsistent. I'll have to look at data from my last fillup, but my though is, the previous time I filled up, I didn't get as much fuel in as it should have, and today, I did get 'enough' in - resulting in traveling that 230 miles on less fuel than was actually in the tank.

Saavy??

I'm about to put a new battery in the car, so I'm thinking the ECU will reset and the fuel maps will be relearned. I'm wondering if it will also relearn the fuel level?

I'm also wondering if I may have an issue that's causing the pump to stop prematurely, leaving me with varying actual amounts of fuel relative to completely full.

10-28-2008, 10:43 AM	#3
FrayAdjacent Registered User Join Date: Dec 2006 Location: Austin, TX Posts: 939	I think I'm having more issues than just a hinkey fuel gauge... I fill up the car every time at the pump. Meaning, I let the pump run until it stops. I do not try to squeeze in more fuel after that point, because my experience is that when the pump stops, the tank is FULL. It will overflow a little if I try to squeeze more fuel in. A few weeks ago, I 'topped off' from a little above 3/4 tank because I was running down to Houston, and wanted to have as much fuel as I could before I left. I think the pump cut off before the tank was full, since I was expecting to put in about 2-3 gallons, and only got 1.5 or so in (iirc). I also record my fuel consumption and calculate fuel economy - and that 'tank' came out to 33mpg! I thought it may be an anomaly with the pump and went about my life. After that fillup, I have noticed that when I fill up, the fuel gauge needle is never on top of or over the dash for Full. It's always a bit below. Yesterday, the low fuel light came on a few miles from home. I had about 220 miles on the trip gauge (which I reset every fillup). I figured this is probably a symptom of the fuel gauge calibration issue I'm seeing. Today on the way to work, I filled up with 230 miles on the trip gauge, and put in 13.47 gallons. That comes out to a fuel economy of 17mpg!! The car's MPG gauge is showing me 26.2, which is slightly higher than the average I usually calculate. I should be hitting 24-25. So I'm thinking something is wonky with the tank or evaporation system causing my fillups to be inconsistent. I'll have to look at data from my last fillup, but my though is, the previous time I filled up, I didn't get as much fuel in as it should have, and today, I did get 'enough' in - resulting in traveling that 230 miles on less fuel than was actually in the tank. Saavy?? I'm about to put a new battery in the car, so I'm thinking the ECU will reset and the fuel maps will be relearned. I'm wondering if it will also relearn the fuel level? I'm also wondering if I may have an issue that's causing the pump to stop prematurely, leaving me with varying actual amounts of fuel relative to completely full. __________________ 2001 Boxster - Grey on Grey 1969 911T Targa - 'Stinky' http://www.zoto.com/frayadjacent/img...f27a-4a399.jpg <---- my car. ^ crap I post. "The existence of the flamethrower is evidence that someone, somewhere once said 'I want to set those people over there on fire, but I don't want to have to walk over there to do it.'"