850 t5 Fuel consumption

[vpcukTommy]

I have finally found a t5, collected it on saturday, so far im happy enough with the car, but having a few problems.

Fuel consumption is pretty bad, im lucky to get 60-70 miles from £20 (116p/l) Bp ultimate

Under heavy acceleration theres alot of smoke, and sometimes theres no boost at all.

I will get some pictures up soon.

[Colin850]

If my calculations are right then that works out at roughly 18mpg.
I have a fairly heavy right foot and can average as low as that if not lower on a particularly fast drive. So it all depends on how fast you were driving.
The black smoke and lack of boost really doesn't sound good though!

[vpcukTommy]

Thats a mixture of driving.
When i first bought the car i took it for a spirited drive on the motorway, when i came off the motorway i noticed the smoke, it was a bit like an old diesel. When its idling its fine no smoke at all, there does seem to be quite a strong smell of petrol tho.

[AlanG]

What colour is the smoke? Strong smell of petrol suggests a leak buddy..

As for no boost.......start by checking for leaks..

[vpcukTommy]

The smoke is black. A leak would suggest the high consumption i guess.

[Johnny5]

I can get 26 - 28mpg average if i drive with a very light right foot, if im giving it some large (which i often do) it can go as low as 14 - 17mpg ave. The smoke doesnt sound good tho Is it using oil?

J5

[danny-R]

them figures do seem a bit low, since fitting my 18t i put £20 of tesco 99 (approx 18.5 litres) and i have done 105 miles and my light has come back on.
not sure exactly waht that is but my computer saus around 26mpg. hth

[Mrs_PA]

I get around 310 miles from a full tank on my 850 T5, Mr PA gets around 290, so your figures are low. Have a look at the oil, is it black and gritty? Any sign of water? Black smoke would suggest a problem with rings (oil being burnt in the cylinder) and strong smell of petrol could be either a leak or a buggered O2 sensor chucking too much petrol in the bores.

[Alan M]

Black smoke usually appears from an overfuelling problem. You could have a coolant temp sensor problem, a fuel pressure regulator problem, an injector problem, a lambda sensor problem. I would get the fault codes read from the diagnostic box or OBD plug depending on which it has. I stored fuel trim code could possibly lead you to diagnose the problem but a little investigation work is required.

[RollingThunder]

It sounds like its overfuelling a lot - I'd check the intercooler pipes and vacuum pipes for splits/leaks. This would seem to be confirmed if you're not getting boost ?

[cameron]

Sorry to Hijack slightly

But how do i check for fuel leaks, i got a right old wiff of petrol this morning, quite un-nerving

On the fuel consumption figures, i have had mine as low as 12ish and had it as high as 45 just depends on how you drive it and wether its auto or manual will also make a difference

[RollingThunder]

Sorry to Hijack slightly

But how do i check for fuel leaks, i got a right old wiff of petrol this morning, quite un-nerving

Easy. Same way as checking for a gas leak - take one match...


(sorry)


Best bet is to check the fuel lines and their connections for signs of leakage - its not as easy as it seems as the fuel will evaporate leaving little trace. One way to check (if its dry) is to use chalk on the joints - just lightly smear/cover the joints with chalk then start the car. Although the fuel will evaporate, it should leave telltale marks in the dust. Thats the theory anyway - I've never done it myself.

Obviously if the smell is strong, I wouldn't advise a DIY check, but would take it to a garage - apart from anything else, they should have good fire extinguishers!

[cameron]

Its sorted

The hose that comes off the end of the metal fuel line and into the injector rail had split at both ends allowing the petrol to freely pour out once the car was running



I knew there must have been a leak somewhere as i was always at the petrol station every other day and i wasnt driving it about that much.

Cheers anyway guys

[The Flying Moose]

Glad you sorted it, that could have had some nasty precussions.

[vpcukTommy]

Thanks for your help guys.

I think it is an O2 sensor, going to plug it into the computer to check, but would that cause the loss in power as well?

[RollingThunder]

Glad the leak is sorted out Cameron.

Tommy, its possible that it is an O2 sensor, however don't assume that it is faulty - even if the fault codes highlight a faulty unit. Leaky hoses often cause the same errors to be logged - and are cheaper to fix Of course it may be the sensor, but do some checking of the hoses first.

[cameron]

Just been a wee run, 5.4 miles, before i fixed the fuel leak i had a juddering like blocked injector syndrome, but now its gone

Fuel average has went from 17.3 up to 23.6, the run was all in 30mph limit with speed bumps all over so not a smooth run by any means, but well chuffed its sorted itself out

[MrMopp]

speed bumps

What are those we dont see those in these parts lol

[cameron]

Lucky you

Probably the reason my wishbone bushes ( Replaced ) and top mounts are knackered ( lowers bought awaiting uppers )

Should ask them to fork out for new bits for my car as its rattling itself to bits.

[RollingThunder]

Lucky you

Probably the reason my wishbone bushes ( Replaced ) and top mounts are knackered ( lowers bought awaiting uppers )

Should ask them to fork out for new bits for my car as its rattling itself to bits.

Damn right. They made our street a 20mph zone and liberally dotted speedhumps of various designs all over the place. Not good in an 850R with the lower suspension - I hold my breath every time. The barstewards