Poor Diesel MPG!!

[Batman]

Hi Guys, I'm guessing theres already a thread out here about poor Diesel MPG, but here my story so it's not lost amongst someone elses thread.

I've got a 57 plate 1.9CDTi SRI 150, with just under 16k on the clock, it looks the part, and drives beautifully, but..............I seem to getting poor MPG!!

I've filled up the tank on Sunday, re-set the tripometer, and initially, the MPG was ok, around 45 around town, but now its dropping, FAST!

I'm now at between 32.8 and 33.2, and when I filled up, the rang said I could travel 425 miles, then it went up to 470, even when I'd travelled 50 miles after filling up, so I thought I'd be home and dry.

I'm now showing a range of 385 miles, and I've used up 1/8 of the tank to travel a total of 70 miles. Its stop-start milage, hardly done motorway apart from a blast last week to Nottingham before re-setting the figures.

I've even driven at 60 mph in 6th for about a mile and a half, and the MPG didn't get higer than 33.2!!

I've checked the engine bay, no sign of leaks, no diesel patches on the floor where I park on the road.

Anyone know where I'm going wrong?? Wasn't going to post this thread until i'd used up the tank and work out my actual MPG to the display MPG, but seeing the range drop so much changed my mind. I'm guessing some of you will say that as my range went up to 470 while driving, it's settled down and is correcting itself, but it's the MPG i'm worried about.


Thanks in advance!!

[Sean-2.2Direct]

Wow thats really bad I get around 39 - 42 in my 2.2 direct petrol thats on motor way
some other oil burners will be along soon mate to suggest somthing

[neverlandandy]

id be interested to hear an answer to this as my computer says 37mpg same car as yours and same sort of driving conditions

[Batman]

I'm kind of hoping its an air filter problem, not enough air causing more fuel to be used, but i'm not a mechanic, and its a guess. If it is a problem with the air filter, what would the cost be for a new one? thanks neverlandany and sean-2.2Direct for replying so quick!! was only posted a few minutes ago!!

[Duncan]

Is it an auto?

[Sean-2.2Direct]

I'm kind of hoping its an air filter problem, not enough air causing more fuel to be used, but i'm not a mechanic, and its a guess. If it is a problem with the air filter, what would the cost be for a new one? thanks neverlandany and sean-2.2Direct for replying so quick!! was only posted a few minutes ago!!

Your welcome mate.

Not to sure if it would be the air filter but they only cost £8.50 from vauxhall not much and really easy to change
Not sure if it could need the firmware updating

[Batman]

Nope, it's a 6 speed Manual. I do 'occassionally' put my foot down, but nowhere near enough to cause that drop in MPG as far as I know. should i take it back to the dealership?? Think I've got a 3 month warranty with them, but it's still in its Vauxhall Warranty too. Should I take it back or will they just laugh me out the showroom??

[Sean-2.2Direct]

No they wont laugh mate there is no way in hell you should be getting 32 mpg even if you keep it in 1st gear all day long.
I used to cane my cdti alot and did not get any lower than 40

[Batman]

Never thought of the firmware to be honest. Never had a car with an ECU that could be updated before. (Last car was a 1.3 Petrol Kia Rio - Quite a step up to a Veccy)

[Sean-2.2Direct]

btw mate before you do go back to Vauxhall how are you getting these calculations? have you tried resetting the trip computer and see what happens?