Mpg, wtf??

davek0974 · Sep 26, 2011

Hi all,

My mpg reading has dropped markedly on the last fill up but I can only think of two things that I have done.

First I gave her a short service, oil, filters, transmission lube job etc.

Second I bought a new set of grabber AT tyres.

Would either of these account for the 10mpg drop I saw when I updated fuelly today?

Bit ****ed off as cash is tight

Any thoughts?

I have just checked for filter leaking, fuel lines leaking and also checked the oil level for fuel in it.

Discodad · Sep 26, 2011

Tyre pressures.

Dippypud · Sep 26, 2011

If it's your '94 300Tdi your talking about, then yeah, tyre pressures, roof-rack, two ton of junk in the back or even worse some bastid stealing it...

we had some twit round our way popping the fuel caps and taking out a gallon here and there, been chased and almost caught twice, little fooker I will shoot 'im.

davek0974 · Sep 26, 2011

Do GG at's need higher pressures?
Always run 26f and 35r before now.

The vehicle has not changed since I have had it, always had roof bars, no junk at all in boot, no signs of tampering with fuel etc. Just a sudden drop between two fuel-ups, normally around 33-35, this one was 27, best ever was 37.

Discodad · Sep 26, 2011

I noticed mine had drastically dropped last year.
read this LINK
I'm now running at 38 PSI and loads better. But I normally drop back to 28 when I'm playing in mud.

davek0974 · Sep 26, 2011

Bloody heck, seems very sensitive if it is that.

I must admit that she drives much quieter now, even the mrs commented that all the knocks and bangs had disappeared! But if the price for that is 8mpg then I'll fill the beggars up with cement

In the meantime I'll try 35psi all round for starters.

biolandy · Sep 26, 2011

Also there was a predicted cold snap for October-(seems funny now its the warmest all year)The fuel companies add more naphtha to derv in cold weather,to stop waxing-winter derv mix has less energy in it,so less mpg-this might be part of your problem

davek0974 · Sep 27, 2011

Just a quickie...

The grabber AT's I have I presumed had All Terrain treads but on the side they are stamped M & S which I thought meant Mud and Snow? Are there different types of AT tyre as I know running mud tread on roads is not generally good.

Discodad · Sep 27, 2011

Are we talking General Grabber AT2 tyres?
If so only one model as far as I know.
If you read the spec on their page for the AT2 it states "Meets the severe snow service requirements of the RMA and RAC"
Maybe something to do with that, but thats all.
Source

davek0974 · Sep 27, 2011

Ok thanks, it was just a thought.

I'll whack the pressure up all round and see how the next tank of juice goes, if it's gonna cost me 6-7 mpg though, I might look into some road biased tyres and flog these ones, it might seem insignificant but over the life of a set of tyres it adds up to big money, which haven't got.

davek0974 · Oct 18, 2011

Update

Filled her up tonight, the first time since upping the Grabbers to 38psi all round, and were back to 33.9 mpg

I am a happy bunny again and I'll do my hardest to treat the old girl to a new set of swivel oil seals this weekend

Watch that tyre pressure guys!

Mpg, wtf??

davek0974

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Discodad

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Dippypud

Never Knowingly Understood

davek0974

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Discodad

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davek0974

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biolandy

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davek0974

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Discodad

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davek0974

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davek0974

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