Fuel loss and cat damage.

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- Neil Brownlee
  
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posted
19 years ago

Thu, Aug 12, 2004 10:40 AM

One for the experts ;-)

I am losing fuel - I'm pretty sure I'm not burning it. On a constant run from 0 miles to 225miles I use 60/65 litres of fuel. This equates to 100 miles in the first 1/4 of the guage, 75 in the second and 50 in the third. If I drive to a place, say 50 miles away after filling up and driving normaly, park up overnight, start up in the morning - the guage happily stays in the place I'd expect, until I hit the first corner/hill and it drops and "loses" me 50 miles seemingly!

I know it's not the guage, as it's the amount of fuel I put back in that hints that I'm losing it. Is this "normal" or is something not quite right in there?

It's a 4.6 V8i running through a 3.9 Y-pipe with cats - which have begun to rattle since replacement in March (OEM - £1800!?!). Can anyone tell me if the 4.6 needed different cats?

Vehicle is a 97 Discovery.

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- grege
  
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posted
19 years ago

Fri, Aug 13, 2004 7:52 AM

By my calculations, that works out at about 17 mpg. The 'official' fuel economy figures for a 1997 V8i Discovery [see link below] suggest around 19 mpg, so I don't think you're far off at 17. Welcome to the world of V8 engines...

formatting link

--> Greg

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- Tim Hobbs
  
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posted
19 years ago

Fri, Aug 13, 2004 8:50 AM

Doesn't sound too awful. Ignore the gauge - mine is hopeless, though better than a lot of other cars. You might expect the 4.6 to be a bit more efficient than a 3.9, but then you have a lot of other crap (sorry, essential off road kit) bolted on. Mine does 18mpg on petrol, a little less on gas, on standard wheels and no essential off-road kit fitted.

As for cats, well I paid £600 for mine replacing with non-genuine ones and I haven't noticed any major difference over OEM. If they are rattling I'd check the fittings haven't worked loose - mine did.

If you think you have a leak, fill it to the brim and leave it a day or too. See if you can get any more in after that. A leak is usually obvious if it's from the tank end - in the engine bay I guess it could just vaporise without being detectable.

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- Tim Hobbs
  
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posted
19 years ago

Fri, Aug 13, 2004 8:53 AM

Oh, meant to say...

I get 300 miles comfortably on a full tank before the yellow light really starts to worry me. I have had 320 miles on several occasions, and once I managed 340 miles in the depths of Lincolnshire, which apparently is served by only 3 petrol stations, 2 of which are closed down. It was a brown trouser moment really, due to the 8 and a half month pregnant missus getting more than slightly stressed and we all know what that can bring on!