Fuel Gauge..

[saneesh8]

My Z's fuel gauge works in a different way than the other cars that i have. For the first 100 miles, it will move only 1/4th from full. Then for the next 100 miles, it goes to the red area and the light comes on. It is not gradual. Is this normal for this car? I have like this since i got the car. Drove almost 3K like this. Never had any issue with fuel pump or anything like that.

[PbFut]

Search Techron. Likely your sender is dirty.

[thomas88162]

That seems a bit off, but keep in mind the Z's fuel tank has an odd shape to help weight distribution, so it isn't too accurate in the first place.

[saneesh8]

For the fuel system I did Fuel Filter replacement, Techron fuel system cleaner, Replaced injector seals and then RXP.

I will search for Techron. Is it same as Techron fuel system cleaner.

Is there a way to clean this sender? I guess 1/2 tank should drive 100 miles (200 is i get for 10 gallon fill up for city drive)

[Vintage42]

My Z's fuel gauge... For the first 100 miles, it will move only 1/4th from full. Then for the next 100 miles, it goes to the red area and the light comes on...

Going to 3/4 in 100 miles might be normal for a 6-cylinder in mixed suburb/city driving. But going to the red zone and warning light in 200 miles could indicate a real problem with the gauge or sender or the tune of the engine. But first you must know the actual mpg your car is getting, to judge the gauge. For instance, if you actually used 12 gallons when the red light came on at 200 miles, that would be 17 mpg which might indicate an engine problem.

The Z3's fuel gauge is not linear so even after you get it working properly, you will need to learn your mpg by checking each tank (divide miles by gallons), and also remember the miles for each mark on the fuel gauge. That will give you the basis for always knowing you many miles and gallons are left in the tank.

For instance, I know my 1.9 gets 30 mpg per tank on a trip, and 27 mpg per tank in my usual suburban rural driving. I see that in usual driving, the 3/4 mark is reached at 140 miles and the 1/4 mark in 280 miles. When I fill up at the 1/4 mark, it takes 11 gallons. The tank holds 13.5 gallons.

Because the Z3 fuel gauge is so inaccurate (non-linear), you need to practice mental math to understand what it is telling you, and how much of the tank is used and remains in terms of gallons and miles.

Or disregard the gauge and just watch the trip meter and divide its miles by 27 mpg (in my case) to know approximately how many gallons have been used and how many remain.

[saneesh8]

I always check by the odometer. So the mpg is proper

[Terry F.]

I always check by the odometer. So the mpg is proper

Me too. I reset at every fill-up.

Terry

[SNR727]

There's a few other threads on this. It's one of those "loveable" things the Z is known for. I've had 3 of them, and they all had the same issue. (Or similar) - leave the house with a half a tank, get to the freeway and the light comes on...

Most of us just go by the odometer and reset at every fill up. Mileage varies depending how much time you spend above 4k, and if you have a 1.9 or a 3.2- but somewhere around 220-250 miles you're probably due at the gas station.

Warning though- the car has personality. Mine sure does... Typically I can count on at least 220 miles before the light comes on- but sometimes, and typically when I'm not in the mood- the light will surprise me and kick on around 180.

When that happens, I tell my girlfriend that my MBZ E430 v8 gets substantially better gas mileage than the Z, so maybe it would save money if I converted the M Roadster to a V8.

Over time she's come to say things like, "Are you sure? I mean if you're going to do it, wouldn't it make more sense to get the V10?"

And then I usually shut up.

[saneesh8]

Mine is not M version. City drive..always ~20 mpg.

[Bigcjim]

Yeah the fuel gauge is a mystery today I showed a bit over a quarter tank in the garage drove less than five miles and the light came on drive five more and could not squeeze eight gallons in the car. It is frustrating mine is a 1.9.

[2002Z3]

My 2002 will stay on full for nearly 90 miles, then drop like a stone to 1/4 full then slow down until the warning light comes on. I usually fill up before then. Figure about 200 for a tank. Yes it will be beter than that mostof the time, but that is a safe time to refill.

[saneesh8]

So i guess mine is normal?