Fuel Gauge Crap Or Fuel Consumption Crap?

[jtek 0]

right, when i got my 205, we were driving it down the motorway back home and the car used about 25-30 quid in 150 miles? it stunk of petrol to be fair so i assumed it was running rich. so i changed the ECU temp sensor and today replaced the AFM for a newer one, which has had an effect on the idle. however i put 10 quid of fuel in yesterday, and i have done probably about 30-40 miles, and the gauge has gone right down already. the car hasnt been driven particularly hard, with the odd blip every now and then. My gauge seems to take ages to rise at the start of the journey then it is all over the place. ther car doesn't seem to smell as much of fuel as it did, wth only a slight smell on idle. any ideas why i could be getting crap economy, or are the gauges just that inaccurate?

thanks

[jackherer 543]

Anything below half on the gauge is wildly inaccurate IMO, the only way to measure the economy is to fill it up, drive x miles, top it up with y petrol and then do the maths.

[DrSarty 90 1 Cars]

If you've got a smell of fuel, I wouldn't suspect rich running, I'd suspect a fuel leak.

 

I've experienced 4 causes of leaks:

 

1) The tanks are plastic and can split anywhere, especially if you ground out on something. I've also had a Citroen BX tank crack on the top somehow?

 

2) Between the tanks near the rear beam your 2 metal fuel lines jubilee clip to 2 rubber lines. I've managed to strike ground (in a Cornish road rally) and weaken one of these exposed joints enough to leak.

 

3) Fuel filter banjo bolts/washers poorly fitted

 

4) Split/perished fuel hose near filter to rail.

 

I'd search for a leak my friend. Lay down some brown. clean cardboard on level ground; park and observe. Likewise check hoses & filter when running.

 

Good luck.

[Richie-Van-GTi 71 2 Cars]

another one to watch out for is the pipes in the wheel arch below the filler cap, I didnt even know I had a leak there until I brimmed it one day and seen a large pool appear on the forecourt.

[Ahl 4]

Anything below half on the gauge is wildly inaccurate IMO, the only way to measure the economy is to fill it up, drive x miles, top it up with y petrol and then do the maths.

Like he says. Work out how much MPG its doing first.

[jtek 0]

cool, i've been watching the mileage as the fuel goes down so i will see what its at when the light starts flashing at me again, and i'll have a look at the fuel system today, see if there's any leaks

cheers

[DaveK 0]

25 quid to 150 miles sounds about right to me, id regularly do 110 mile trip and it would cost about £16-£20, expensive i know but fun

[Guest harry snotter]

heavy right foot

[DrSarty 90 1 Cars]

heavy right foot

 

We all do that with our 205s, BUT, you don't get a fuel smell with enthusiastic driving. Leak I tell you AND poor economy through joyous driving combined. I'm getting nearly 400 miles out of £35 of jungle juice and I absolutely bladder the arse off my valver ....

[jtek 0]

well i checked for any leaks yesterday and i must admit i couldn't see any, however i then stumbled upon another issue that is the car seems to run out of revs past 5500 ish, as if its hitting an imaginery limiter. it pulls cleanly elsewhere however. could this be a fuel pressure regulator that may be playing silly buggers? and not working well at lower revs thus letting too much fuel through? just a thought, thanks for your advice so far

[DrSarty 90 1 Cars]

The leak (my opinion) might not be apparent then when either the engine's not running or it's just sitting there, i.e. not a gravity leak. Potentially then, if performance is down you say, then a fuelling leak in the line somewhere near the carbs which worsens as demand builds (read: you boot it or take it passed 5k).

 

I'm no expert but I gather the fuel line pressure will be constant as a result of the pump's capabilities; I believe it's 2.8bar on a GTi pump. If the leak appears when the engine's running it should be easy to spot, still on clean cardboard watching for drips, perhaps revving it and also checking the engine bay lines. Liekwise the carb(s)' float chamber could spring a slight leak underload (i.e. when the engine moves), maybe even loosening a feed line?

 

These are just my ideas and I'm still convinced, PURELY based on you mentioning a fuel smell, that there has to be a purge in your fuel line somewhere.

 

I accept I could be wrong, but no car I know of smells of petrol unless there's a leak. Exhaust gases maybe, hot oil on a manifold, catalytic convertor smell, but not unburnt petrol.

 

Good luck.