T4 Session and MPG

[Nigel1516]

Hi all.
I seem to be getting really poor MPG from my CDTi. Brim to brim approx 325 miles. I believe this to be approx 22 to the gallon. I do mainly do 2 miles journeys to work and back, but surely it should be better than this. I emailed a local Mg/Rover specialist a couple of days ago, and he said he would have to put my car on a T4. My question is, could this diagnose the problem ? or is it a way for him to make more money. Incidentally the car drives fine, there seems to be no loss of power. I have changed air filter, PCV valve and fitted a EGR bypass.

Nigel.

[Tam]

Not had my car hooked up to T4 yet but after reading this recent thread from BigRuss below i will definately be getting maff and injectors balance checked at some point!.

http://www.the75andztclub.co.uk/forum/showthread.php?t=77783&highlight=screenshots

[HarryM1BYT]

Hi all.
I seem to be getting really poor MPG from my CDTi. Brim to brim approx 325 miles. I believe this to be approx 22 to the gallon. I do mainly do 2 miles journeys to work and back, but surely it should be better than this. I emailed a local Mg/Rover specialist a couple of days ago, and he said he would have to put my car on a T4. My question is, could this diagnose the problem ? or is it a way for him to make more money. Incidentally the car drives fine, there seems to be no loss of power. I have changed air filter, PCV valve and fitted a EGR bypass.

Nigel.

2 miles from a cold start and twice a day - 22mpg is impressively good. What do you think you can expect over such a short regular distance?

Try driving it a sensible distance and check the mpg.

[crashmarks]

I agree with Harry in 2 miles its not likely to be getting warm enough to reach its best thermal efficiency. Try filling the tank zero the miles and go for a decent run, say 50 - 100 miles, a trip to the coast may be. When you get back fill her up and see what you got. If its anything like the norm then theres probably nothing wrong. Also before you set off set the dash diagnostic to check what temp the engine is reaching. should be somewhere in the upper 80s or above if your lucky. If the best you get is mid 70s then you probably need a new thermostat.

[kully]

Those short journeys do kill fuel economy. My wife's 1.2 Ibiza normally does 46-49 MPG on my commute of a-roads and motorway, when she was working just over three miles away, that dropped to around 32-33MPG.

Still 22MPG does seem low.

[Roverron]

Hi all.
I seem to be getting really poor MPG from my CDTi. Brim to brim approx 325 miles. I believe this to be approx 22 to the gallon. I do mainly do 2 miles journeys to work and back, but surely it should be better than this. I emailed a local Mg/Rover specialist a couple of days ago, and he said he would have to put my car on a T4. My question is, could this diagnose the problem ? or is it a way for him to make more money. Incidentally the car drives fine, there seems to be no loss of power. I have changed air filter, PCV valve and fitted a EGR bypass.

Nigel.

The T4 will show whether the maf is overfuelling. This is probably the commonest cause of very poor mpg although you should probably not expect a massive improvement.
Such short jouneys are not good for the engine and it needs a good thrashing once a week.

Ron

[Nigel1516]

Thanks Ron.

Its really frustrating, as I have purchased a Synergy 2, and a Pierburg Maf from your website. I had not given it a thought about informing the insurance company, and now I am worried how it will affect my premium if I do tell them. So in the meantime Synergy etc. remains in the jiffy bag.

Nigel.


The T4 will show whether the maf is overfuelling. This is probably the commonest cause of very poor mpg although you should probably not expect a massive improvement.
Such short jouneys are not good for the engine and it needs a good thrashing once a week.

Ron

[crashmarks]

Didnt change my maff but I did fit a synergy Admiral charged me an extra £26 for the year which I thought was ok. Give them a ring you may be suprised if its a bad suprise then shop around and when the time comes renew elsewhere. I would try the synergy with the orional Maf first.

[lamuff]

I agree with Harry in 2 miles its not likely to be getting warm enough to reach its best thermal efficiency. Try filling the tank zero the miles and go for a decent run, say 50 - 100 miles, a trip to the coast may be. When you get back fill her up and see what you got. If its anything like the norm then theres probably nothing wrong. Also before you set off set the dash diagnostic to check what temp the engine is reaching. should be somewhere in the upper 80s or above if your lucky. If the best you get is mid 70s then you probably need a new thermostat.


sorry im new to 75s does my 02 2.0 cdti connie have this diagnostic thingy ? and how do i access it ?

[Nigel1516]

sorry im new to 75s does my 02 2.0 cdti connie have this diagnostic thingy ? and how do i access it ?

Yes, I believe all 75's have onboard diagnostics. I can't remember how to do a link, but look in the "how to" section, or search "onboard diagnostics" and you will find it.

Nigel.