Poor MPG 2.3 T5 v70 x-reg

[jteez]

Don't laugh...please!

I've been reading a number of posts and it seems that people get widely different mpg's from their daily runners... I don't have high expectations, but... it seems almost as bad as my old 5.4L 7-series without a fraction of the performance...

Basically I think my volvo's a little lacking in maintenance to say the least. I'm lucky if I get 25mpg on a run and long term average is 21mpg (at a little over 70mph . The most I've ever seen running on petrol at 50mph is 27mpg.

I could let you into some more secretes:

• It is converted to LPG (should account for 10% less than petrol...?)
• Smokes a little under WOT
• Is fast but doesn't seem really fast
• Very embarrassed to admit, but I only notice hearing the turbo spin at low speeds when I've got round to topping up the oil...
• The tip of the exhaust is pretty sooty
• Run's smoothly except sometimes for less then a minute it will skip a beat of two when idling at start & occasionally idles a little lumpy

So I've seen a lot of people over 30mpg (if they're being ultra careful). I know you have to feather the throttle, etc and I used to manage this on my 7 series at 50mph (I did have cruise control to help mind you, though long term average was 21mpg ). But I seem so far off it on this v70...

So basically where should I start looking for increasing the mpg? What general maintenance is going to have the biggest effect on mpg? I've never worked on a car with a turbo and not used to the way they drive yet either.

Thanks in advanced!

[M-R-P]

Here's a few driving tips,
Light on the throttle, anything over 2500rpm allows the turbo to spin up using more fuel.
Change gear early, into 4th at 20mph and 5th at 30 mph don't try to accelerate from 30 in 5th cos it won't like it but will sit happily at 30 in 5th with cruise on and return about 54mpg.
If you want performance, make sure you're in a gear that lets you sit at 3500rpm before you put your foot down - you'll be on boost and in 2nd and 3rd, she will fly.

As for maintenance, performance wise, change the oil, air, and fuel filters. Flush the engine and replace the oil. A coolant change wouldn't hurt as the turbo is oil and water cooled.
Do these and see where you are. If you can get your codes read too that might help.
Hope this helps.
P.S. Got any pics of the car?

[t5_monkey]

Sounds like your MAF is tired and you need your injectors cleaning FPS can also give a drop in consumption.

[Steveh24]

This mpg does seem a bit low as my S60 T5 does on average about 29 mpg and I'm not that gentle with the accelerator pedal, but there are lots of things that can cause bad mpg, not just the driver.

Steveh24

[jteez]

Thanks for the quick replies!


And was toying with the idea of getting some Jag wheels



Is carb cleaner any good for MAFs on these... I'm very wary of touching MAFs after I broke one on my 7-series trying to clean it with isopropyl and Q-tips Are they sensitive to genuine volvo ones or are aftermaket ones ok?

What is FPS? The engine seems very clattery as well. Not in a knackered engine way but a 'relatively' light tapping. Could it be the injectors? Camshaft? Don't know what type of engine this has inc. valve control?

I could hear a slight rushing of air at idle from the engine bay as well but could identify where it was coming from... Does the turbo pipe work sound like that at idle? Where's the PCV as I've read about that causing problems? I pulled the dipstick out: it didn't smoke at all and the o-rings looked good. It was a bit sludgey at the bottom so def could do with an oil change

I was thinking there's no point doing the fuel filters as it's bad on both LPG and petrol, but stupidly didn't occur to me that both might be clogged, lol!

Definitely try the mega low revs stuff, not how I normally drive

Haven't tried the volvo software but plugged in easyOBD today, no codes thrown but was surprised by how high the temp got (105C at one point before the fan kicked in) and the air intake was up at 50C. The gauge on the dash was reading normal though. That was idling at approx 2000rpm with external temp of 24C (ish). I'm not familiar with reading fuel trims and stuff but noticed that the O2 sensor was dancing all over the place, especially whilst on LPG (0.1V-0.6V) which is a little strange???

Probably be a couple of weeks before I get round to do a full on service but I'll definitely update routinely as I know how beneficial these forums are to everyone reading them as well as me !

...so the saga continues

Thanks guys.

[t5_monkey]

FPS - fuel pressure sensor.

Most sensors have a lifespan.

[M-R-P]

Ok, a few answers...
No smoke from dipstick and oil filler cap means pcv is ok.
These engines run hot naturally.
The tappu noise is the hydraulic tapets/valve lifters - should be cured/helped by an oil change.
don't know about the O2 sensor!
Bosch MAF's bought from anywhere other than a Volvo main Stealer will cost about 80-120 quid - cheap ones don't usually last.
Carb cleaner will be ok - be gentle.
Rushing air noise is normal (depending on how loud).

Nice pics, kinda looks familiar!

[jteez]

Great, thanks! I'll keep you all posted!

[LeeT5]

Thanks for the quick replies!


And was toying with the idea of getting some Jag wheels



Is carb cleaner any good for MAFs on these... I'm very wary of touching MAFs after I broke one on my 7-series trying to clean it with isopropyl and Q-tips Are they sensitive to genuine volvo ones or are aftermaket ones ok?

What is FPS? The engine seems very clattery as well. Not in a knackered engine way but a 'relatively' light tapping. Could it be the injectors? Camshaft? Don't know what type of engine this has inc. valve control?

I could hear a slight rushing of air at idle from the engine bay as well but could identify where it was coming from... Does the turbo pipe work sound like that at idle? Where's the PCV as I've read about that causing problems? I pulled the dipstick out: it didn't smoke at all and the o-rings looked good. It was a bit sludgey at the bottom so def could do with an oil change

I was thinking there's no point doing the fuel filters as it's bad on both LPG and petrol, but stupidly didn't occur to me that both might be clogged, lol!

Definitely try the mega low revs stuff, not how I normally drive

Haven't tried the volvo software but plugged in easyOBD today, no codes thrown but was surprised by how high the temp got (105C at one point before the fan kicked in) and the air intake was up at 50C. The gauge on the dash was reading normal though. That was idling at approx 2000rpm with external temp of 24C (ish). I'm not familiar with reading fuel trims and stuff but noticed that the O2 sensor was dancing all over the place, especially whilst on LPG (0.1V-0.6V) which is a little strange???

Probably be a couple of weeks before I get round to do a full on service but I'll definitely update routinely as I know how beneficial these forums are to everyone reading them as well as me !

...so the saga continues

Thanks guys.

Not meaning to step on anyones toes, but when you first start the engine from cold, you may hear a slight tapping noise that should quickly disappear. This is normal and is just the Hydraulic lifters filling with oil. The only other engine noise you may hear (other than exhaust) should be a slight clicking noise. This is also normal and should be constant. It is just the Injector solenoids opening and closing.

PCV oil trap is under the inlet manifold. The remaining parts of the PCV are in the form of various pipes and hoses. Not a 5 minute job and done properly will involve removal of inlet manifold. It is well worth doing and if your car is around the 100k mark then a simple test will confirm if it needs replacing.

Simply: warm the engine by driving for 10 - 15 minutes (no need to rag it).
Once warm, pull over on flat level ground and let engine idle for 5 miutes. With engine running, open bonnet and slightly pull out engine oil dipstick about 2". If white 'Choo Choo train' type smoke can be seen puffing from the dipstick tube then guess what? YEP, You need to replace your PCV system complete.

Main dealer only parts and for a 850/v70 P1 is about £70. P2s are around the £155 mark for ALL the parts. Some people just change the oil trap, or clean it out. i would advise against this as you will only have to strip it all out again in less than 50k. Do the job properly and it will last another 100k and save your rear main seals from blowing.

[M-R-P]

I think all the bases are now covered, Jteez there you go mate. Keep us updated.

[LeeT5]

...Ref your air intake temp at 50 degrees, well think about it....it would be as the car is stationary. All the hot air from the engine bay is just swarming around the engine and entering the intake. When your driving then the temp will be ambient air temp due to the replenishment of fresh air and RAM air entering the intake.

[jteez]

AMAZING!

So shook the dead bugs out of the air filter (I know it's terrible, I will replace it but when I do the oil & filter as well, not sure if oil returns/breathers will mess a new one up). Sprayed loads of carb cleaner.... and guess what!

30MPG!!!! up from a previous high of 24.7mpg! And it's not juddering as much at low revs (which is one reason I wasn't driving eco/gently)!

So thank you all for you advice! Loving the 'old man' pull away from the lights but still able to gun it a little and don't loose to much MPG!!! This is fantastic!

As the MPG's were rising I had a little De Javu... I think when I picked up the car it did do 30mpg. However I then didn't use it for 6months. When I started using it I had forgotten that and it was down in the low 20's. I wonder....
...does the MAF clean it's self like some others, (by over-heating when you switch the ignition off and vapourising gunk on them)? If so, maybe, not being used for so long may (and consequently not cleaning itself) enabled 'gunk' to get really stuck on requiring a 'proper' clean!!! Just a thought! Then being dirty, underestimates the airflow??? misinterpreting that as load on the engine resulting in a richer mix???
---just an idea

Thanks anyway!