Thread: Fuel economy???

Originally Posted by Infiltrator

Hi There

I keep pretty good records on my fuel economy on my 2000 Disco 2 TDi5 and most of the time I average around 11.28 L\100 - but on my last fill - I had a very nasty suprise.

It has shot up to 17.67L\100!

I did do a lot more short drives to the shops and back but i didnt go offroading does 17 sound a little too high???

is it possible i got some crappy diesel and have blocked my injectors / fuel filter or have I just been hooning around more than I thought??? What else could have gone wrong???

Best regards,
Shannon

Could also be a dodgy bowser??? Is it same one as you normally use? There are a couple of variables here - the way it was filled, whether the fuel meter on the bowser is accurate, whether you filled it the same as normal (it could have had an air lock for some reason), and whether the vehicle has an issue.

I'd see what the next reading is, before doing too much. In the mean time, check the diesel - take some from the bottom of the diesel filter and see if there is water in it, as there may still be some residual. As well, look at the usual suspects - oil in the ECU loom, any diesel smell around the car when parked (lots of diesel smell if there's a leak that effects the consumption that much), dragging brakes, low tyre pressure (this should only drop the fuel economy by 5 to 10% though) etc. If the economy is as bad, then perhaps throw in some injection cleaner (cost effective maintenance sell a good one, others are ok as well - others will debate if this should be used at all). Check around the fuel pressure regulator to see if it is leaking - others may be able to say if the fpr failing causes consumption to go up,as I haven't got direct experience of this (not talking about the direct leak, but the loss of pressure causing consumption to go skywards).

I had a dunnydore once where the fuel consumption when from 12 to 17 to 20 litres/ 100km. The valve stems were failing, causing the plugs to foul up, with the fuel consumption going up. Not much oil being used, although it was noticeable. So, keeping an eye on fuel economy does help to indicate that there may be other problems. Got it checked / rectified after two refills were really bad, even with my wife driving. Boy, can she drive cars really economically.

Buy yourself a can of good quality electronic contact cleaner and give your Air flow meter (MAF) a clean out. If there is no change get your air flow meter output readings checked by a LR specialist.

MAF being dirty or faulty is a common fault of high fuel consumtion on TD5's.

Alternately make sure its not going into the sump.

I replaced my MAF at about 85000km with a new VDO unit due to high fuel cons amongst other things. Now back down to about 12L/100km on average.

Cheers

Dave

Ive just purchased a hawkeye so I can read the codes. I'm figuring that it may save me some money in the long run.

hopefully it will tell me if theres a problem with the MAF

Originally Posted by Infiltrator

Ive just purchased a hawkeye so I can read the codes. I'm figuring that it may save me some money in the long run.

hopefully it will tell me if theres a problem with the MAF

In most cases it won't log a fault code if it is playing up it will just provide the ECU with an inaccurate reading. Best to compare with another at the same time or throw up your reading on a post here for some advice from the posters.

Cheers

Dave