Gas Mileage Issue

[jameshk]

I have a 2001 996TT which I bought used. I have replaced the fuel pump since then. I am getting only 220Km per tank of high octane gasoline. No apparent leaks, no smells of fuel-can't figure out what is going on. Would appreciate any help or direction you might be able to provide.

james

[greenboxster]

The problem may be located under your right foot. :P

I've found my first couple tanks haven't lasted very long either. Then again, I have been watching the boost-o-meter more than the fuel gauge.

Steve

[fdss]

The problem may be located under your right foot. :P

I've found my first couple tanks haven't lasted very long either. Then again, I have been watching the boost-o-meter more than the fuel gauge.

Steve

You're probably not completely filling the tank either. There are posts that people are getting a few gallons less that the capacity of the tank.

[hooster]

The problem may be located under your right foot. :P

I've found my first couple tanks haven't lasted very long either. Then again, I have been watching the boost-o-meter more than the fuel gauge.

Steve

You're probably not completely filling the tank either. There are posts that people are getting a few gallons less that the capacity of the tank.

I recall problems with a gas flap in the tank for those years for both 911s and 986s. As said, you're probably not filling the tank completely and you don't realize it, because the pump is stopping you.

[Chuck Jones]

fdss is right........the problem is directly tied to your right foot....I can get 22 mpg and eek out a 23.6 if I set the cruise control and let it drive itself on the freeway....but invariably I set the onboard computer LCD output to boost and see if I can nail 1.0. That results in a meager 13.5 mph most of the time. I routinely only get 200 miles out of a tank of gas.

[greenboxster]

....but invariably I set the onboard computer LCD output to boost and see if I can nail 1.0.....

My wife and I took our turbo to Roebling Road near Savannah on Saturday and had to fill up 3 times. What a blast! I saw 151 just before the Turn 1 brake marker. :o

And today is my 2 week anniversary with the car. Honeymoon's still going...

Steve D.

[TAndujar]

I have a similar problem with my GT2. The fuel gauge/on board computer indicates that the fuel tank is empty and the tank fills with 55-60 liters. A few weeks ago I confirmed that the gauge/on board computer are not showing the correct fuel level in the tank by driving the car 100 miles with the fuel gauge marking empty. I filled it up with 70 liters.

I am convinced that the problem with my car is the fuel gauge/on board computer/fuel sender are not working properly.

[RFM]

TAndujar

Go to your dealer for a fuel tank level recalibration.

[TAndujar]

TAndujar

Go to your dealer for a fuel tank level recalibration.

The dealer has calibrated it several times. The Porsche service rep authorized the change of the sender unit located at the tank.

[Chuck Jones]

Steve D: I've had mine 3 months, and the honeymoon just keeps going. I don't think it'll stop....well maybe when gas hits $5.00 a gallon. Gotta' pitty those Britts for the cost of their gas...

[jameshk]

I have a similar problem with my GT2. The fuel gauge/on board computer indicates that the fuel tank is empty and the tank fills with 55-60 liters. A few weeks ago I confirmed that the gauge/on board computer are not showing the correct fuel level in the tank by driving the car 100 miles with the fuel gauge marking empty. I filled it up with 70 liters.

I am convinced that the problem with my car is the fuel gauge/on board computer/fuel sender are not working properly.

thank you for the reply and those of others. I had the same problem as you as well as the original one cited. When my warning light (message) says refill the on board computer is telling me I have 100Km or so left before a refuel is required. As suggested by others a recal sorted this problem out. AS for fuel usage, I certainly understand the "right foot" point of view. I also understand math 65 litres into the tank and 200Km =horrendous mileage. Nothing to do with whether the tank is filled or not.

thanks for your time

james

[fastboydave]

Steve D: I've had mine 3 months, and the honeymoon just keeps going. I don't think it'll stop....well maybe when gas hits $5.00 a gallon. Gotta' pitty those Britts for the cost of their gas...

Pity away Chuck, we are paying £4.99/gallon (approx $10/gallon) for high octane Shell 99 RON. Even the cheap stuff (95RON) is $9.40/gallon. OK, our gallon is slightly larger, but what a tax rip off!!! But hey, its all worth it........... i guess??

Incidentally, my mpg with all round types of driving (motorway, stop go traffic etc) is 18-20ish, and i dont hang about either.

[4G64T]

I am getting approm 8 - 10 Miles per gallon or 4 - 5 Kms per litre City Driving. This is about what I always expected. Its all to do with the right foot and the bigger the smile you get as the heavier your right foot gets.

[Chuck Jones]

Fastboy: You folks are buying by the litre, so it is a slightly larger volume than the gallon, but that still exceeds our prices by quite a bit. Also, we're getting 91 ROM here, and you folks...even with your "cheap stuff" are up to 95. I wish we had some place around here that routinely sold 95. There are only a very few stations that sell the higher octanes. Otherwise you have to buy racing gas....or I'll buy Toluene by the 5 gallon can and mix it in with the 91 for my 87 930S.

You mentioned you are getting 18-20 mpg.....but wouldnt' that also be metric in KPG? Therefore a bit less in the MPG conversion? I'd be on the seventh step of Nirvana if I could routinely get 20mpg out of it during spirited driving. But as so many will say....you didn't buy ia 996TT to whine about gas consumption.

[Danyol]

I get 19 mpg on a run and as low as 14 with "spirited" driving...how can one avoid it, the car begs to be run (like Dash in the Incredibles!) :jump:

Edited January 17, 2008 by Danyol

[fastboydave]

Fastboy: You folks are buying by the litre, so it is a slightly larger volume than the gallon, but that still exceeds our prices by quite a bit. Also, we're getting 91 ROM here, and you folks...even with your "cheap stuff" are up to 95. I wish we had some place around here that routinely sold 95. There are only a very few stations that sell the higher octanes. Otherwise you have to buy racing gas....or I'll buy Toluene by the 5 gallon can and mix it in with the 91 for my 87 930S.

You mentioned you are getting 18-20 mpg.....but wouldnt' that also be metric in KPG? Therefore a bit less in the MPG conversion? I'd be on the seventh step of Nirvana if I could routinely get 20mpg out of it during spirited driving. But as so many will say....you didn't buy ia 996TT to whine about gas consumption.

Chuck, we do buy by the litre yes, but my calcs were to 'our' gallon which is 4.54 litres. My figures of 18-20 mpg are from my on board computer in the main clock (set to MPG (UK)), which i reset each time i fill up. Dont know how acurate it is, but i get that kind of MPG with my daily commute (crawling traffic, stop start, few overtaking manouvers etc) and weekend driving (motorway and open roads more). Obviously, the roads in our tiny little country are a little jammed up and you cant 'toe it' every time, but i do my best!!! Ofcourse, i may get little better mpg due to higher octane fuel. I believe this helps??

[DrSheily]

Conversion Rule: To convert from Gallons to Liters, multiply the number of Gallons by 3.7854 and,

to convert from Liters to Gallons, multiply the number of Liters by 0.26417

[fastboydave]

Conversion Rule: To convert from Gallons to Liters, multiply the number of Gallons by 3.7854 and,

to convert from Liters to Gallons, multiply the number of Liters by 0.26417

For the US gallon yeah. But i was talking about UK gallon, which is 4.54 litres. So when i talk about $10/gallon (UK) in my previous post, that is because we are charged £1.10/litre (approx $2/litre), therefore a gallon (UK) is £1.10 x 4.54 = £4.99 (approx $10).

[Chuck Jones]

Fastboy wrote.... therefore a gallon (UK) is £1.10 x 4.54 = £4.99 (approx $10).

I'm going to quit bitching about the cost of gas in California. My sincere condolences sir.

Out of curiosity, today I filled up and went to visit a friend 120 miles away. I set the cruise control so that I maintained a steady speed at around 2900 rpm in 6th. The terrain was freeway from sea level up to about 1800 feet and thru several small towns...and managed to get 21.2 mpg....which is the best I've ever gotten....but it took all my self control to keep from tromping on the accelerator when goaded on by some folks...so you can get fairly decent mileage if you stay out of the boost....but that ain't no fun.....most boring trip I've ever taken.

As a quick add-on for today...which is Feb 1st....I decided to very judiciously be a tenderfoot for an entire tank of gas. Most of the driving was on freeways with the cruise control set to 2600-2800 rpm. This rpm range seems to get the best mileage. I did about 20% of the driving on city streets, but came off of stoplights by shifting very slowly and gradually bringing the car up to cruising speed. I was really surprised to get approximately 310 miles out of a tank of gas. Up to this point, I was getting from 175-210 miles out of a tank. By driving "judiciously" I increased my travel range by a good 25%....so these cars can get some fairly decent mileage if you stay off the accelerator....but now that the test is over....time go go back to getting 200 miles out of a tank. :) I was amazed when I'd set the onboard computer readout to "Miles left before refill" and watch the LCD readout. I had 39 miles left according to the indiator...I left my house to go downtown and the readout showed 39 miles before fillup was needed. As I drove on the freeway, the calculator increased the miles left from 39 all the way up to 48....in other words I was increasing remaining mileage on the fly. Idrove a total of almost 34 miles and when I got home the indicator still had 29 miles left on it. I had no idea I could get this sort of mileage and never tried this before....probably won't try it again until gas hits $4 a gallon. Don't shoot at over how these cars aren't meant to be driven that way....this was just a test under real conditions to see what was possible through restraint.

Edited February 1, 2008 by Chuck Jones