FAP Fluid priming?

fred1 · Post by **fred1** » 07 May 2010, 10:40

Hi,

Fuel gauge on C5 appears to work by registering the actual tank contents at fill up and when the engine is turned off and restarted. In between times it calculates the level by measuing how much fuel is being used.

I found this out when I suffered a large leak from a filter connection whilst on a motorway journey.

Fuel gauge behaved as normal but I got an increasing smell of diesel.

When I pulled into a service area to investigate, the gauge was still showing 3/4 full. When I stopped and subsequntly restarted the engine, having first fixed the fault, the gauge showed empty! This was confirmed by the fuel it took to fill the tank.

John

Post by **Paul-R** » 07 May 2010, 10:45

fred1 wrote:Fuel gauge on C5 appears to work by registering the actual tank contents at fill up and when the engine is turned off and restarted. In between times it calculates the level by measuing how much fuel is being used.

I know, it's dreadful isn't it.

It also needs at least 10 litres of fuel to be put in before it even acknowledges that anything has been added. I regularly top up jut 5 - 10 litres in order to brim the tank for accurate fuel consumption figures and roll out of the fuel station with exactly the same reading on the gauge.

Of the cars I've ever had I distrust the C5's gauge more than anything else. There should be option that the Lexia can set along the lines of "just tell me what the sender unit in the tank is reading".

cachaciero · Post by **cachaciero** » 07 May 2010, 16:13

jimleshed wrote: As mine is an early C5, I will need a Lex with the older type 30 pin connector/adaptor I guess. Probably of chinese origin. Will take a look at Fleabay.

No 16 pin std connector is what you need.

cachaciero

jimleshed · Post by **jimleshed** » 07 May 2010, 18:20

We'll see then, have ordered one....

cachaciero · Post by **cachaciero** » 10 May 2010, 16:31

myglaren wrote:I always run mine until I get the low fuel warning the it accepts around 62 litres.
Supposed to be a 65 Litre tank but I have managed to get 72 in on one occasion.

Probably a cold day

cachaciero

Post by **myglaren** » 10 May 2010, 17:18

cachaciero wrote:
myglaren wrote:I always run mine until I get the low fuel warning the it accepts around 62 litres.
Supposed to be a 65 Litre tank but I have managed to get 72 in on one occasion.
Probably a cold day

cachaciero

Just the opposite, it was a swealtering day in early September the year before last.

cachaciero · Post by **cachaciero** » 10 May 2010, 19:54

myglaren wrote:
cachaciero wrote:
myglaren wrote:I always run mine until I get the low fuel warning the it accepts around 62 litres.
Supposed to be a 65 Litre tank but I have managed to get 72 in on one occasion.
Probably a cold day

cachaciero
Just the opposite, it was a swealtering day in early September the year before last.

Interesting I wonder just how fuel pumps meter, the amount of energy you are buying is proportional to weight not volume. Volume varies with temperature and in the case of diesel that's quite a lot.

cachaciero

MikeT · Post by **MikeT** » 10 May 2010, 20:57

jimleshed wrote:We'll see then, have ordered one....

Pity I didn't see your thread earlier - I'm in Christchurch if it's not too far to travel and am offering free sessions to FCF members.

Post by **myglaren** » 10 May 2010, 20:59

I presume that there was just a faint whiff of diesel left in the tank that day. Fuel pumps are checked for accuracy fairly frequently I believe and this was quite a recent installation.

jimleshed · Post by **jimleshed** » 11 May 2010, 09:18

Thanks MikeT, but I've ordered it now, and waiting with bated breath for its arrival.
I'm sure when it arrives I'll have a few questions....