HI,
anyone knows how big is the tank in 05 STR?
i has mine about 12 gallon and i had about 70 miles to empty.

does this have anything to do with the fuel pressure?

thanks

 

I have an 06 STR and the total capacity of my fuel tank is 18 gallons plus the reserve.

 

thanks
i thought so too.. i m sure its 18 gallons.
but why i m only filling up at 12 gallon and my gauges are already down to 70miles to empty.

any idea?

 

Because the fuel tank/gauge system design is a f*cked up mess on these cars. Don't count on anything you see from the gauge or the computer to be terribly precise.

When I fill it up the gauge starts dropping as I exit the gas station. I get about 15-20 miles on the first indicated 1/4 of tank. When I calculate actual mileage versus what the computer says the mileage is a couple mpg better. Best I ever see is 20.7 (calculated) on long runs using cruise control. It's joke of a system.

There are two free-formed fuel tanks that are squeezed into irregularly shaped voids in this car with multiple fuel pumps to get the fuel to the engine. I suspect these problems have something to do with that fact.

I've never put more than about 14.5 gallons in the tank and that's when it says I've got less than ten miles left. I guess there's some fudge factor in the system but having a computer tell you such BS doesn't inspire confidence.

I suppose we should add this one to the annoying list thread.

Bob S.

 

Odd. I find my calculated average mpg matches the car closely.

Not short term, as that's defined to be based on how you've recently been driving and thus does reflect what should be expected based on that definition. If you imagine thrashing it - maybe on a track day - then filling up, I'd want it to tell me a lower range than otherwise as the best the car can guess is that you'll continue thrashing it. Which is what the car does.

I've never wanted to run the tank too low as I know the fuel cools the pumps and they're not cheap to burn out & replace (and the idea of a very hot pump in a tank of vapour is kind of scary). So, the most I've filled at any time is 58l (about 12.6 of our gallons, I think 15.75 of yours).

 

Tank holds 69 liters

 

So I had about enough fuel to get to the next filling station in some parts of this country - good! I like a reserve.

 

thanks guys
i do agree this is an annoyance if we can't even trust the gauges to tell us the accurate amount of gas left in our tank.
i end up filling the gas every 12 gallon.
i might try to bring this to the tech sometime today. and post whats the diagnosis.

merry x'mas to you guys.

 

The only "accurate amount of gas" it could tell you would be quantity (gallons, litres, etc) because the mpg varies so widely (from say 3mpg to 43mpg). Would you really want quantity? If not, what would you want (bearing in mind it is literally impossible to give an accurate distance)?

It already estimates distance based on how you've been driving. The estimate will be accurate IF you keep driving the same way. But who does.......

 

The STR has a different fuel system from the standard S Type. Yes the factory capacity is 69.5 L or 18.3 gallons.

The STR uses two high volume pumps feeding the engine directly. The standard S Type and the Lincoln LS use one pump to feed the engine and a transfer or jet pump to keep the two sides of the fuel tank even. The low fuel light comes on early on purpose. The factory uses the fuel to cool the pumps and wants you to fill up while the pump is still submerged. This is not unique to the STR. My old SHO did the exact same thing.

I have found the average fuel mileage is what the car uses for distance to empty. So look at your fuel mileage, if it's pretty low from driving in town your DTE (Distance To Empty) will also be low.

I have put a maximum of 15.5 gallons in but I know it holds a couple of gallons more so I don't worry to much about hitting 0 miles.
.
.
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I can understand that if as you say you're driving around town but most of my observations are based on highway travel. I haven't heard anything here that changes my opinion about the fuel information system on this car. Depending upon the car most of my cars have at least 30 miles left once the low fuel light comes on. Like you I believe this one probably does as well but I just don't want to run below zero miles left.

Non linear or inaccurate fuel gauges are not unique to Jaguar either but this system presumes to inform the driver of quite a bit of information all of which I find inaccurate.

Bob S.

 

I agree. They should probably delete that display. But they could try and have an accurate fuel gauge. Maybe it's just hard given the dual tanks and multiple pumps. Mine goes from F to 3/4 VERY quickly.

The 44 gallon tank in my Suburban reads over full for quite some time making you feel really great about how efficiently you're driving a tank that gets 14 mpg downhill with a tail wind. Most of the time it's 10 mpg. Eight or lower when towing something heavy. By the time you hit the half full mark you're under 40% left.

 

There's a documented reserve, isn't there? Are you allowing for that?

Even so, bearing in mind that the pumps need cooling, how empty do you want to go i.e. how much do you want to risk your expensive pumps?

 

I've heard people mention the cooling issue on here but don't know if it's true. I have other vehicles with in-tank pumps and I've never heard of that being an issue. If 3 or 4 gallons must always remain for that purpose then effectively we don't have 18 gallon tanks do we? That sill doesn't explain all the other issues with this system.

A simple warning light for when you've hit the reserve and then let the operator make the judgement is probably the best.

I've run out gas twice in my lifetime and both times I ended up getting laid ...

 

I can beat that - I've only run out once

Oh, hang on, I lose - I didn't get laid

I can't recall the reserve but think it's 2 gallons.
What are "all the other issues"?

 

2 years ago, ( a few months after I got the Jag) I had the "floppy" gas gauge problem, which most likely was from the previous owner letting the tank go too far down causing the jet pump to overheat and fail. It would fluctuate between ~ 3/4 and ~3/8 full over a short time. Luckily, it was fixed under factory warranty, otherwise, it would have been $900-$1000 for the dealer to fix it.
DON"T let the tank go under 1/4 full if you can help it, keep the pumps cool.

 

I think we just got done discussing those starting with post #4.

The biggest being the gauge irregularities.

 

There doesn't seem much in there once you factor out the fuel reserve, which appears to have been overlooked, and that estimates depend on your recent mpg. Maybe I just spend more time looking at the road and other vehicles than the gauge LOL

 

Bob, I think the guage irregularities you speak of may be an issue with your particular car.

John (jagV8) has run MPG tests and his comes out spot on. I have too and my computer is always dead on. I'm sure others have as well. I'm going to check my owners manual for warnings about running low on fuel. I do know that Jaguar (for what ever reason) calculates against a lower fuel capacity than the tank holds; like others have said, around 15 US gallons. This isn't just the S Type either.. Top Gear did a MPG challenge and Jeremy had an XJ diesel that still had quite a lot of fuel left despite running the last 50+ miles of the test with the computer and guage showing 0. I was funny because he actually wanted the car to run out of fuel.. There was a part where he just kept yelling at the car to run out..

 

Bob,

If you run out of gas in your STR, you may or may not wind up getting laid. But if you burn your fuel pumps up in the process, you'll certainly be getting screwed....