Volvo S60 2.5T AWD increased fuel consumption

Jonty

Hi all,

I have a Volvo S60 2.5T petrol that is gone harder on fuel lately. There are no codes thrown up and so far I have done the spark plugs, air filter, cleaned the throttle body and an oil change. I also changed the intercooler pipe to the manifold.

There is 170K Kms on it. Can a MAF sensor get lazy and not throw up a code? Also should I check the O2 sensors?

Any ideas??

Jesus.

Has it gone up by much? The weather's been pretty bad, that can count for a couple MPG's

biko

Have you used the brimming method to get an exact reading of mpg?

Jonty

Its gone from 11.7L/100Kms to 12.8L/100Kms.

It was about 11.7L/100Kms in winter last year

Jonty

biko wrote: »

Have you used the brimming method to get an exact reading of mpg?

Yes

biko

I suppose that's from the computer?
Have you verified with brimming method?
Or do you fuel up more often/spend more?

Jonty

No I'm in Canada,

I know how to work fuel consumption - Fill to the neck, drive, go to the same pump in the same petrol station to refill and record litres and divide by the number of KMs covered.

It ties in with the trip computer to about .1L

Jesus.

I wouldn't mind the Computer reading but you've brimmed it and its down 2 MPG. That's not an awful lot. Perhaps you've been doing slightly more urban driving?

Jonty

Not really, Its mostly highway driving

biko

Isn't it like -30 in Canada at the moment?

As Jesus said, that isn't much of a drop and small things like tyre pressure or too much junk in the boot can account for parts of it.

Jesus.

Jonty wrote: »

Not really, Its mostly highway driving

Hmm. I think the difference is neglaible mate. If it was over say 5 MPG then I'd start thinking there might be something wrong. Slight fluctuations like this are quite normal. My MPG moves up or down 2 or 3 with most tanks even though I do pretty much the same trips.

That's my tuppenceworth anyway bro

Jonty

biko wrote: »

Isn't it like -30 in Canada at the moment?

Yeah, but it went harder on juice before the big freeze. I might bring it to a main dealer for a code reading.

Labour is 115 bucks an hour here in a Volvo garage

Jesus.

They're a sweet motor those S60's aren't they mate? If I lived in north America I'd drive something similar.

You can get away with an S40 with a 1.6 in a tiny Country like this. A Country where if you put your foot down in a powerful car you could end up in the sea! But in the wide open vastness of Canada/USA, you need something bigger with a bit of power behind it.

Jonty

Jesus. wrote: »

They're a sweet motor those S60's aren't they mate? If I lived in north America I'd drive something similar.

You can get away with an S40 with a 1.6 in a tiny Country like this. A Country where if you put your foot down in a powerful car you could end up in the sea! But in the wide open vastness of Canada/USA, you need something bigger with a bit of power behind it.

The lads in work take the piss out of me over it saying its an auld lads car

Jonty

Just an update, it's gone up from 12.8 to 13.7L/100km in the last 2 weeks. Routes haven't changed or weather hasn't changed.

Jesus.

Jonty wrote: »

Just an update, it's gone up from 12.8 to 13.7L/100km in the last 2 weeks. Routes haven't changed or weather hasn't changed.

Strange indeed Jonty. Maybe you should take it for a service after all.

Jonty

I got the plugs and air filter done myself. I'm going to take the platic cover off from the top of the engine and see if I can detect any vacuum leaks around the intake manifold.

Supergurrier

T5's aren't exactly the most economical to begin with

Jonty

Aye, but she's gone harder on the stuff lad! It's not a T5 though, it's only the low pressure turbo version

Jesus.

Jonty, didn't you have freaky cold weather in Canada this year? Were you calculating your MPG during this spell or had it subsided?

Jonty

The car was getting harder on fuel all the time, and now the weather is backed off a bit and it's still getting crap mileage.

So, I know there could be a few numbers at play:

Winter Fuel,
Temperature,
Vacuum leaks,
Sensor Issue (MAF or O2)

We're still on winter fuel, but consumption did not get this bad lasst year. I will check for vaccum leaks before I give it to a mechanic.

Edit - I will check tyre pressures, but I have checked no calipers are binding.

Andrew_Doran

Hi, the below is probably not the answer to your problem but maybe it'll provide some food for thought.

I had poor fuel consumption on the 2.0T version of that engine last year. In addition the throttle response was jerky and it eventually started cutting out at idle.

The dealer tool (VIDA) showed a dodgy MAF correction factor (0.7ish, should be 1.0) on the live readout and also a high air leakage factor. There was also a code stored for boost/vacuum leaks/clogged PCV system but the engine light was not on. Being turbocharged the vac system is quite complicated.

I cleaned the throttle body, replaced all vacuum/PCV/turbo control lines with new fuel hose, removed intake manifold and cleaned the muck out of the tiny vac ports, cleaned the turbo control valve with carb cleaner, replaced the oil trap (which was clogged with sludge) and cleaned the sludge out of the oil return ports on the block. It was a miserable job but it fixed it completely.

PS: The turbo Volvos seem very sensitive to spark plug choice (as I learned the hard way). The consensus on internet forums seems to be to fit genuine Volvo only. They are not expensive from memory. PPS: Its said to use fully synthetic oil only as semi can cause them to sludge up, which I would well believe after doing that fun job.

Jonty

Thanks.

I'm not suffering idling difficulties or cut outs. The PCV system was replaced last year, and I have a new throttle body fitted.

I'm thinking it's a vacuum or sensor issue, but will not rule out anything out.

Thanks!

Andrew_Doran

Jonty wrote: »

I'm thinking it's a vacuum or sensor issue, but will not rule out anything out.

Being a turbo you can safely do both a vac and a pressure test (up to 1bar or 15psi, ish) because it has a couple of one-way valves in the vacuum piping. Due to the one way valves there are a couple of bits that will only be tested by doing both.

Yakuza

Could the weather be having an effect on the fuel? Do you buy the same fuel from the same garage? (Just thinking of ways to eliminate sources of difference)

Jonty

Just an update.

Fuel consumption back to normal. The main culprits were:

Winter Fuel
Excessively low temperatures
and I hate to admit it, I was down a few psi on all 4 corners.

Thanks for the help

visual

Good to see update and positive conclusion