fuel consumption

pclarke82 · 22nd November 2012, 07:39

hi all, i put a post up last week about my fuel consumption, i've come back to read replies and its been deleted? would anyone know why?

greendriver · 22nd November 2012, 07:41

There was some down time on the forum which took out a lot of posts & replies

pclarke82 · 22nd November 2012, 07:57

ah may explain it, ok i shall ask again lol. My consumption on my 1.8t is getting beyond a joke, im about 10mpg. i do sit in a fair whack of traffic but this is getting silly. im always refueling. I cant smell petrol when i stop, everything else seems fine, sometimes the engine idles a little stuttery but not always. Only thing i have done is re-gap my spark plugs to .5 as i was hoping to cure my misfire.

Any ideas as to what could cause such poor consumption?

sraddave · 22nd November 2012, 08:06

Quote:

Originally Posted by pclarke82

ah may explain it, ok i shall ask again lol. My consumption on my 1.8t is getting beyond a joke, im about 10mpg. i do sit in a fair whack of traffic but this is getting silly. im always refueling. I cant smell petrol when i stop, everything else seems fine, sometimes the engine idles a little stuttery but not always. Only thing i have done is re-gap my spark plugs to .5 as i was hoping to cure my misfire.

Any ideas as to what could cause such poor consumption?

Just to let you know I average 30mpg, still not great but probably about right.

You say you have a miss fire? Have you checked the small boost pipes

pab · 22nd November 2012, 08:54

Very excessive fuel consumption, to say the least..

My initial thoughts would be a fuel leak at the tank or associated pipework to the pump, but as you say, you can't smell the fuel. If the leak was after the fuel filter and in the delivery pipes to the inlet, the engine would fail to start as the ECU would recognise the loss in fuel pressure.

Certain sensors around the engine send signals to the ECU regarding the fueling, if one of these sensors is sending the wrong reading, over fueling will occur.

You mention that the car has an erratic idle, the coolant temperature sensor can have this effect and will over fuel the car as the ECU thinks it's still in a cold state.

Perhaps a session on a T4 can pin point the issue.

chrissyboy · 22nd November 2012, 09:46

i agree with pab car needs to be put on t4 or any reader with live data to show how the mixture is.02 sensor can be giving a wrong reading so car is over fuelling ,misfire ca be a leaking inlet manfold gasket ,a misfire will also increase the amout of fuel used ,engine temp sensor can too cause over fuelling and a misfire, check ht leads coil packs too

SD1too · 22nd November 2012, 17:25

Quote:

Originally Posted by pclarke82

My consumption on my 1.8t is ... about 10mpg.

Phil,

How are you measuring this? I hope you're not using the movement of the fuel gauge because this will be enormously inaccurate. The trip computer is reasonably good provided that you zero it before using a whole tankful. Best of all is the brim-to-brim method, again measured over a whole tankful.
Do you do a lot of short journeys? Check the digital display of the coolant temperature. I'd expect something like 90 degrees at least.

Quote:

Only thing i have done is re-gap my spark plugs to .5 as i was hoping to cure my misfire.

You should find out what is causing your misfire. The plug gaps should be left at the manufacturer's setting.

Simon.

T-Cut · 22nd November 2012, 20:19

Quote:

Originally Posted by pclarke82

I'm about 10mpg. I do sit in a fair whack of traffic but this is getting silly. I'm always refueling. I cant smell petrol when I stop, everything else seems fine, sometimes the engine idles a little stuttery but not always.

You couldn't burn at 10mpg if you tried. You have a fuel leak.

TC

438brad · 22nd November 2012, 20:47

I dream of getting 10 mpg in traffic......however thats in my 5.7l V8 Holden!

rover54 · 22nd November 2012, 21:04

If you truly getting 10mpg then you are in 'on choke' fuel comsumption territory. Assuming it starts and runs OK then I suspect your problem with be with the Oxygen sensor reading a lean mixture and the ECU trying to compensate by overfuelling. Get it on a OBD reader and see what faults are recorded, clear them and see what new faults appear.

22nd November 2012, 07:39	#1
pclarke82 Regular poster MG ZT Join Date: Oct 2012 Location: Kingswinford Posts: 77 Thanks: 0 Thanked 0 Times in 0 Posts	fuel consumption hi all, i put a post up last week about my fuel consumption, i've come back to read replies and its been deleted? would anyone know why?

22nd November 2012, 07:41	#2
greendriver This is my second home MG ZTT 180 in Poseidon Join Date: Feb 2011 Location: Croydon Posts: 3,745 Thanks: 44 Thanked 86 Times in 75 Posts	There was some down time on the forum which took out a lot of posts & replies __________________ *None of my troubles are Rover*

22nd November 2012, 09:46	#6
chrissyboy This is my second home lovely little ford focus. Join Date: Jul 2009 Location: East Dulwich Posts: 7,877 Thanks: 2 Thanked 82 Times in 68 Posts	i agree with pab car needs to be put on t4 or any reader with live data to show how the mixture is.02 sensor can be giving a wrong reading so car is over fuelling ,misfire ca be a leaking inlet manfold gasket ,a misfire will also increase the amout of fuel used ,engine temp sensor can too cause over fuelling and a misfire, check ht leads coil packs too __________________ [ I'm really confused. -I keep dreaming I'm an insomniac

22nd November 2012, 20:47	#9
438brad Gets stuck in MG ZT-T 260 SE (#491) Join Date: Mar 2010 Location: Rossendale Posts: 753 Thanks: 94 Thanked 23 Times in 22 Posts	I dream of getting 10 mpg in traffic......however thats in my 5.7l V8 Holden! __________________ [SIGPIC][/SIGPIC] My other toys! Holden HSV GTS 5.7 V8. Turboed and Nos '98 Honda Fireblade Mercedes Vito Never mind the power, feel the torque!

22nd November 2012, 07:57	#3
pclarke82 Regular poster MG ZT Join Date: Oct 2012 Location: Kingswinford Posts: 77 Thanks: 0 Thanked 0 Times in 0 Posts	ah may explain it, ok i shall ask again lol. My consumption on my 1.8t is getting beyond a joke, im about 10mpg. i do sit in a fair whack of traffic but this is getting silly. im always refueling. I cant smell petrol when i stop, everything else seems fine, sometimes the engine idles a little stuttery but not always. Only thing i have done is re-gap my spark plugs to .5 as i was hoping to cure my misfire. Any ideas as to what could cause such poor consumption?

22nd November 2012, 08:54	#5
pab Banned MG ZT V6 190+ Join Date: Sep 2008 Location: Leeds Posts: 33,223 Thanks: 41 Thanked 1,614 Times in 1,416 Posts	Very excessive fuel consumption, to say the least.. My initial thoughts would be a fuel leak at the tank or associated pipework to the pump, but as you say, you can't smell the fuel. If the leak was after the fuel filter and in the delivery pipes to the inlet, the engine would fail to start as the ECU would recognise the loss in fuel pressure. Certain sensors around the engine send signals to the ECU regarding the fueling, if one of these sensors is sending the wrong reading, over fueling will occur. You mention that the car has an erratic idle, the coolant temperature sensor can have this effect and will over fuel the car as the ECU thinks it's still in a cold state. Perhaps a session on a T4 can pin point the issue.

22nd November 2012, 21:04	#10
rover54 Retired rover 75 v6 Auto Conn. SE 54 plate LPG and 2006 Rover 75 v6 Auto LPG , 1.8 r75 Manual Join Date: Aug 2010 Location: London Posts: 3,379 Thanks: 0 Thanked 6 Times in 6 Posts	If you truly getting 10mpg then you are in 'on choke' fuel comsumption territory. Assuming it starts and runs OK then I suspect your problem with be with the Oxygen sensor reading a lean mixture and the ECU trying to compensate by overfuelling. Get it on a OBD reader and see what faults are recorded, clear them and see what new faults appear.