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[Andy A]

Just unplugged the MAF sensor and took the car for a run. It ran the same with it unplugged as it did when plugged in. Does this mean the the MAF sensor is OK? 

No fault codes are showing.

The car went through its MOT in March and passed its emissions test, while it was using a lot of fuel compared to usual.

What other sensors could cause the fuel economy to go up and how do I test them?

I have a holiday coming up in a couple of months, up north and want the fuel economy to be back to normal if possible.

[flyer 0712]

I believe if it runs the same with it disconnected then the unit is ok.....have you cleaned out the throttle body and the breather hoses as these clog up with gunge and require regular cleaning..

[zirk]

I take it you really mean Low mpg 2.2 as in Poor, rather than High, if so whats figures are we taking about.

[Andy A]

I believe if it runs the same with it disconnected then the unit is ok.....have you cleaned out the throttle body and the breather hoses as these clog up with gunge and require regular cleaning..

That is what I thought. 

Yes just cleaned the throttle body and still poor fuel economy.

[Andy A]

I take it you really mean Low mpg 2.2 as in Poor, rather than High, if so whats figures are we taking about.

Yes its dropped to just under 16mpg local. Very poor compared to usual through the winter. :-(

[flyer 0712]

Could it be fuel leak,,,,rusted steel fuel pipes that run under the car and maybe being porous and seeping through...Has it had a descent service recently,,plugs etc....silly thing but are tyre pressures correct ??..does it run at the correct temp and get up to temp as it should,,,,,

[Andy A]

Could it be fuel leak,,,,rusted steel fuel pipes that run under the car and maybe being porous and seeping through...Has it had a descent service recently,,plugs etc....silly thing but are tyre pressures correct ??..does it run at the correct temp and get up to temp as it should,,,,,

Will check all tomorrow, rain permitting and time. Will let you know.

Thanks

[Andy A]

Could it be fuel leak,,,,rusted steel fuel pipes that run under the car and maybe being porous and seeping through...Has it had a descent service recently,,plugs etc....silly thing but are tyre pressures correct ??..does it run at the correct temp and get up to temp as it should,,,,,

Checked all of the above including tyre pressures and all is OK.  I did a full service around 2 months ago. 

Temp outside is 13 but the software I was using to check the codes said air temp was 20. Could this cause poor fuel economy? 

[Marks DTM Calib]

No not really, what condition is the coil pack in?

[Andy A]

No not really, what condition is the coil pack in?

Just looked and the coil pack looks in excellent condition.

[Doctor Gollum]

What does the ecu think of the coolant temp? Ignore the gauge 

[plym ian]

I take it you really mean Low mpg 2.2 as in Poor, rather than High, if so whats figures are we taking about.

Yes its dropped to just under 16mpg local. Very poor compared to usual through the winter. :-(

Seems fine to me 

But then again i have a heavy right foot. Mine averages about 17-19 anyway 

[Andy A]

What does the ecu think of the coolant temp? Ignore the gauge 

Waiting for a replacement psu for the laptop to arrive. Will recheck when laptop is working again.

[Andy A]

I take it you really mean Low mpg 2.2 as in Poor, rather than High, if so whats figures are we taking about.

Yes its dropped to just under 16mpg local. Very poor compared to usual through the winter. :-(

Seems fine to me 

But then again i have a heavy right foot. Mine averages about 17-19 anyway 

Mine has always been around 20 on avg but lately down to 16.

[Andy A]

Unplugged the ERG this morning and took it for a short run. The pull of the engine below 3000 rpm was noticeably better. The car picked up speed a lot smoother and with a lot more go below 3000 rpm.

Will cleaning the ERG valve sort the mpg out or will it need replacing with new?

Can I reuse the gasket or is it recommended to replace with new?

I seem to remember that using a blanking plate to blank it off is a better option. What do you think?

[Andy A]

Should say EGR and not ERG. 

[TheBoy]

I believe you can just blank it on 2.2

[plym ian]

Checked mine today and here is the result

[Doctor Gollum]

Clearly not trying




Single figures should be readily achieved 

[plym ian]

Clearly not trying




Single figures should be readily achieved 

I'll give it a go and report back sir

[mandula]

Checked mine today and here is the result

Wow, that's like 14,1 litres/100km.. And I thought mine 9,8 l/100km was high (has been at 8,9 l/100km lowest with just motorway driving) 

[Andy A]

Checked mine today and here is the result

Is that local or a mixed driving?

[Viral_Jim]

Mine, which is an auto estate does 24-26mpg around the doors and up to 30mpg on a run (that's measured tank to tank, not on the car's readout).

I tried all the hypermiling cobblers once and got 32mpg, but after 500miles of it I wanted to hurt myself and those around me, so never bothered again  .

[plym ian]

Checked mine today and here is the result

Is that local or a mixed driving?

Local. If i go on a run i always reset it before hand just so i know

[Viral_Jim]

Ok, daft question time. Have you measured it tank to tank rather than using the gauge/info screen?

You could be chasing a problem in totally the wrong place. Looking for something that's caused the mpg to drop rather than chasing a sensor that's thrown the mpg calculator off.

[Andy A]

Ok, daft question time. Have you measured it tank to tank rather than using the gauge/info screen?

You could be chasing a problem in totally the wrong place. Looking for something that's caused the mpg to drop rather than chasing a sensor that's thrown the mpg calculator off.

No it's not a daft question. Yes, but what sensor/sensors would cause the sudden drop in mpg?

Thanks

[Viral_Jim]

Ahh! Now, youre going to need someone who knows what they're talking about 

I'm not sure what inputs the display takes to calculate the mpg, roadspeed sensor obviously, but on the fuel side... no idea