Running out of fuel/Massively inaccurate fuel gauge

[Toomanyloti]

They are different things.

The line represents the physical fuel level based on the sensor in the tank.

The distance will change (down and up) based on how you’re driving.

If you’re on a track doing 10mpg the range will drop based on that as the computer works it out.
If you then start driving at 30mpg on the motorway the range will rise as your new driving style is taken into account.

The trip computer will have an algorithm to work it out based on mpg over a certain time or mileage.

sorry chap I understand how it works just hadn't picked up the line was a graphical representation of fuel level I thought it was a graphical display of the range number. I would prefer to know quantity numerically.
I just got a photo of the line which is showing full but a range of 230m. I went to get the MPG but its all gone due to disconnecting the battery last night. I think it was about 19mpg as I have been running all over in it mostly in track mode.....of course.
If it holds 58l (12.775 real gallons then 19mpg gives a range of 242m so 230m displayed now seems reasonable.
I have just brought up the image of the gauge and range (in track mode) on my mac and noticed the 1/2 marker which due to my eyes being painted on had not seen before. Forgive the dust.
The manual cleary shows its a level/quantity indicator. Never thought to check
This was at the point that it had run out of fuel...

 

[Toomanyloti]

This is now.....
So its reset all data as I disconnected the battery last night.
I assume the software won't do another calculation until its supplied with new data after a period of time moving?
I will shove it in tour and do a few miles see if it changes.

 

[Toomanyloti]

warnings last night after washing....

 

[Toomanyloti]

Sat in the garage and ran if for a minute or so. Brake warning caption and yellow triangle in amber. No other warnings.
Moved it a few feet back and forth and turned it off. Got out locked it.
Unlocked got in and started engine......
All captions and warnings gone
A friend is heading over with a decent code reader to see if there's anything left lurking in the background.
The only change from yesterday is maybe it 'dried out'??
I still had faults after I reconnected the battery.

Back to the original issue looks like it's the level sensor at fault reading half full when its bone dry.....
I'll induce some 'G' today and see if it makes a difference.

Hope i didn't bore anyone. If I was at the factory I would be all over this data. Surely it must get seen????

 

[Superman]

I would suspect a calibration issue, rather than a mechanical issue. Suggest taking it to your dealer and asking them to investigate... Although they may not have an answer if nobody else has had the issue, they can at least investigate.

 

[Eagle7]

keep it topped up and see if it makes a difference on start parking as you would normally.
When it died it was nose up. When I reversed if back off the road it ended up flat-ish nose to tail but slightly off side down. a gallon made hardly any difference it spluttered but didn't start. Fired immediately with 2 gals

^^ this.

 

[Pugwash]

dunno cant remember to be fair but i think it looked proportional to the numerical range left

Are you proposing that line is the gauge and the range is numerical and not the same thing???

ie the line is NOT a graphical representation of the number?

Correct. It’s not.

 

[Pugwash]

The car should be measuring fuel usage even when stationary. If you pull up one of the trip computers and look at instantaneous fuel consumption, when stationary with the engine running it reads in gallons per hour consumption. It’s only when you pull away that the computer now has some distance data to play with and so it can give you an mpg reading.
As suggested above, could just be a calibration issue.

 

[NicolasB]

Wow. So many limitations. I park the car like it is so I don’t get my car stolen off the driveway and obviously never had these issues before. My first Lotus. I’m wondering if the fuel pump is faulty/too weak and not pressurising to start first time no matter what angle you’re parked.

Try turning things on (button on, but not trying to start), then off a couple of seconds, then try to start. See if that primes the fuel pump. There is oftentimes a check valve type thing that keeps the pressure up after the vehicle is turned off, at least it was that way on some older engines. That way when you jump in and immediately turn on the key it already has pressure in it doesn't have that trouble starting. However, newer cars try to prevent any problems by anticipating that you will be starting the car in the get the fuel pump pressurizing when you open the driver's door or do something similar. Either way, it's not normal for it to struggle to start or sputter to life as you say.

 

[Toomanyloti]

I would suspect a calibration issue, rather than a mechanical issue. Suggest taking it to your dealer and asking them to investigate... Although they may not have an answer if nobody else has had the issue, they can at least investigate.

mmmm I will report it but im going nowhere near the stealers unless it dies completely.

Codes were...
P0700 Transmission Control System - suspect as it juddered to a halt in 2nd gear (Auto)
P0627 Fuel Pump A Control Circuit/Open
P0087 P0087 Fuel Rail/System Pressure- Too Low Bank 1
So running out of fuel and juddering to a halt in gear caused the above. A random code/fail on my mates old discovery caused untold seemingly unrelated codes.

Just done 10miles and it's been fine.

Reversed into drive and get this...

Restarted and its gone.
Bloody thing has more bugs than a tramps mattress

 

[eriegz]

due to my eyes being painted on

This is great, I've gotta use this one.

 

[Porter]

The service manual doesn't have detailed photos of the fuel pump and sender unit, it just explains how to remove it and indicates that it uses a float type level sensor and to tilt the assembly when removing it so you don't damage the float arm.

There's a chance that it's a two-stage unit with a separate priming charge pump, which (if failed) would explain some of your troubles with the car on an angle or when trying to restart after a dry tank fill.

Then again it could just be a weird combination of conditions involving a bad or stuck level sensor. It could even have an internal control that uses the charge pump differently when the sensor indicates low fuel level, which yours doesn't because it's stuck. Lots of potential failure modes here.

 

[KCMO68_510]

Parking on a gradient can cause the fuel to move in whatever direction the car is angled. The reason your car starts fine the second time is because the fuel pump has pressurized the system. If you have to park on a gradient, try turning your car around the other way. It sounds like the way you've been parking is causing the fuel to drain out of the fuel line and away from the pickup instead of towards it.

This is all good for suggestions on what to do with how it currently is, but it just seems odd to me that the tank baffles are not designed well enough to not have to worry about parking angle.

 

[Eagle7]

This is all good for suggestions on what to do with how it currently is, but it just seems odd to me that the tank baffles are not designed well enough to not have to worry about parking angle.

Probably depends on how much fuel is in the tank. The Emira has a 15.8 gallon tank (60 l), so if you're down below the 1/4 tank mark, that's only about 3 gallons or less which is not very much.

 

[Porter]

This is all good for suggestions on what to do with how it currently is, but it just seems odd to me that the tank baffles are not designed well enough to not have to worry about parking angle.

They might work fine but if his pump isn't priming correctly (or the surge pump isn't doing its job, if it uses one), then the baffles won't help.

 

[KJD]

sorry chap I understand how it works

I did think as I was typing my reply that I was giving egg-sucking instructions to Grandma so sorry about that.
But I do think that you were over-thinking the fact that the fuel gauge is a fuel gauge.
Hopefully if it’s a stuck level sensor, it will free up with some vigorous petrol sloshing.

 

[Toomanyloti]

I did think as I was typing my reply that I was giving egg-sucking instructions to Grandma so sorry about that.
But I do think that you were over-thinking the fact that the fuel gauge is a fuel gauge.
Hopefully if it’s a stuck level sensor, it will free up with some vigorous petrol sloshing.

Nah I think we all need to offer whatever we can in support and guidance. If we cant cope with a bit overlap of experience then best go elsewhere. Every day is a school day.
Been messing with cars and bikes all my life but learned a lot on here more than anywhere else.

If I can do anything myself I will to avoid disappointment at the hands of others. I might try the dealer if i get a rod through the block.

I intended setting off and staying in tour...that lasted to the end of the drive as we have a small railway tunnel 20m from the entrance overruntastic.
I completely forgot about doing some sloshing about action totally engrossed in the ride! Dohh

 

[nimbusblack]

my guess would be faulty fuel level sensor in the tank, i had mine replaced 2 weeks into receiving my Emira at B&C guildford, was a 6 hr job and i waited, free wifi and coffee .

 

[Toomanyloti]

Awesome - 3 weeks in here and having someone whos never seen one before rag it to bits

Really grim

 

[Porter]

Awesome - 3 weeks in here and having someone whos never seen one before rag it to bits

Really grim

Uh oh... story?