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Fuel Gauge problem

jockmog

Active member
Joined
7 May 2018
Messages
35
The fuel gauge on my '01, 3.4 Coupe has started to read full all of the time even after driving for more than 200 miles. Any suggestions as to why this might be?
I have just had the front to rear A/C pipe replaced at an OPC and wonder if something has been disturbed. On filling the tank today I noticed that there seemed to be an abnormal amount of vacuum when I undid the fuel cap.
All suggestions gratefully received, thanks.
 
I'd sort it out quick or you'll end up with an imploding fuel tank. At bare minimum, release that vac after every drive to reduce any damage to the tank. It could be that the tank has already imploded and damaged the fuel sender unit.

Have a good read of this, it may help: http://911uk.com/viewtopic.php?t=129613
 
jockmog said:
The fuel gauge on my '01, 3.4 Coupe has started to read full all of the time even after driving for more than 200 miles. Any suggestions as to why this might be?
I have just had the front to rear A/C pipe replaced at an OPC and wonder if something has been disturbed. On filling the tank today I noticed that there seemed to be an abnormal amount of vacuum when I undid the fuel cap.
All suggestions gratefully received, thanks.

As Alex says have a read of my thread on the subject, I did some serious head scratching to get it sorted.

The A/C pipe runs up inside the offside wheel arch liner and there are a few pipes from the tank venting system that were probably removed to get the A/C pipes to route through. I'm guessing something didn't get put back or got damaged in the process?

Take it back to OPC and tell them of this problem, they will totally deny all responsibility so you would need to be there when they strip the wheel arch liner off to witness anything not as it should be.
 
They will be in the area of the carbon canister when doing this work .. do i actually think they have caused this .. no .. im afraid not .

Its either a stuck float on the fuel lvl sensor , it can catch on the pipes in there but normally after work done in the tank ... or the tank has partially collapsed .. this is normally a valve on the canister and nothing on the a/c pipe replacement would cause this .. IMHO .
 
The fuel pump and level sensor assembly were both replaced at the OPC and the car was returned to me yesterday. My first stop (0.5 miles away) was to fill up with V Power but after filling, the gauge only registered a little over half full and it remained there. The OPC claim to have added 30 litres of fuel to calibrate the gauge/sensor but my "Bentley" manual says that for 2WD Carreras the amount of fuel needed for calibration is 12 litres, 28 litres being the amount for the 4WD variants due to the different shape of the tank.
Can anyone confirm the correct amount of fuel required for calibration.
 
jockmog said:
The fuel pump and level sensor assembly were both replaced at the OPC and the car was returned to me yesterday. My first stop (0.5 miles away) was to fill up with V Power but after filling, the gauge only registered a little over half full and it remained there. The OPC claim to have added 30 litres of fuel to calibrate the gauge/sensor but my "Bentley" manual says that for 2WD Carreras the amount of fuel needed for calibration is 12 litres, 28 litres being the amount for the 4WD variants due to the different shape of the tank.
Can anyone confirm the correct amount of fuel required for calibration.

This is one of those that could go round the houses with guesswork. I'd say it's one of those to put back to the OPC and instruct them to sort it out. Confirming quantity of fuel to calibrate is not going to solve the problem. Just hand it back to the OPC to sort out.
 
+1
 
I was hoping that someone might know so that I could inform the OPC because clearly they don't know!
 
You have filled your tank up and it only reads half full .. obviously that's not correct and i would assume the float is catching on something ... there are several pipes in the tank along with wiring .. there is a position mark on the top part you line up to get it in the correct place .

Its been a long time since ive replaced a fuel sender unit im afraid so from memory ..

On a C4s / turbo you have a saddle tank .. parts of the tank go below the sender unit so the remaining distance is calculated .

This type will need calibrating .. from memory it was 25 ltrs .... that's what i remember from the tester when i last did it anyways ... its also a pain in the ass to get it right .

A C2 doesn't have a saddle tank , if the float touches the bottom you have no fuel left and i don't remember there being a calibration for these ..

At best if there is a calibration routine then it would be 13 ltrs .. but i don't remember there being one .
 
jockmog said:
I was hoping that someone might know so that I could inform the OPC because clearly they don't know!

The solution has to be with the OPC. They have access to Porsche Germany's technical team to find a solution. What you you are serking is akin to a diagnosis and then telling a surgeon what is needed.

Just hand it back to OPC, tell them to sort it and suggest if they csnnot sort it, you will take up the matter with Porsche GB.

It is really not complicated. Nobody should know more sbout their brand than the manufacturer and his representative.
 
Its not a complicated system .. it should be easy to fix ..




Trust me .. you deal with UK technical ..

Nice to be told by your Technical department .. we are sorry but we don't know the answer to your question but when you work it out could you please let us know for future reference ...

I Kid You Not !!


Been there .. done that .. moved on !
 
OPC found that the float was fouling on something in the tank. They corrected the problem, filled the tank and delivered the car to my home all FOC. :thumb:
 
It does some times make me wonder .. the lvl sensor was stuck in the first place and probably on a pipe .. not an unheard of fault shall we say ..

They replaced the sensor and fitted it exactly the same way so that it was again sticking on a pipe .. :frustrated:
 

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