ml 270 cdi maf

[Gazz270]

Evening guys,over the last week my fuel economy has gone south to the tune of 19mpg from 32,ive had it on star today and the only thing that has shown up is the maf,
(signal voltage too low).my question is would this cause this much of a drop in mpg.
The car drives perfectly boost okay and has plenty of power,ive checked all the intercooler hoses and intercooler and all looks ok,egr is all working clean and shiney.
I have even disconnected the maf and it immediately drops into limp mode reconnect and all is well, kind of at a loss now

 

[x332race]

Put a new MAF in and find out....a MAF should cost around £55 and is simple to install. Star is telling you that there is a problem with it anyway.

 

[Bobby Dazzler]

MAF failures seem to manifest themselves in slightly different ways, and poor fuel consumption is one symptom. Surprised nothing else is noticeably "odd" though.

If you're still on the original, for how much it costs, it might be prudent to swap it as it can't have much life left in it. We replaced the MAD on our ML in Summer: cost £52 from the main dealer, and was a simple swap (after a little encouragement from BlackC55!!).

 

[Justin1600]

Fairly common on CDI3 engines, stick a new one in with a new Air Filter. When was the Fuel Filter last changed aswell ??

 

[Gazz270]

fuel and air filters probably do need doing,think ill give it a service this weekend along with a new maf,£52 seems reasonable from main dealers.

 

[Gazz270]

fitted new maf and done an engine oil service,made a hell of a difference picks up quicker from standstill and i dont know if its my imagination but gear changes seem a lot smoother also changes up quicker,wil let you know about mpg later in week when i fill up.

Gareth

 

[Justin1600]

fitted new maf and done an engine oil service,made a hell of a difference picks up quicker from standstill and i dont know if its my imagination but gear changes seem a lot smoother also changes up quicker,wil let you know about mpg later in week when i fill up.

Gareth

 

[BlackC55]

In this cold weather my ML uses alot fuel. All the MAF and service items are spot on.

I put it down to the heated seats being on all the time and the wider and heavier winter tyres I now have.

 

[Gazz270]

Bit of an update,mpg still poor.was thinking if ive done anything that might affect it,the only i could think of was i put an oil catch tank in between the breather and where it enters the pipe onto the turbo over xmas.The catch tank works great.
there is a sensor in this pipe and i wondered what it did it looks like it could possibly be a temperature sensor but why would they put one there and would it affect mpg,i am going to put it back as it should be and see what its like tomorrow,ive got a 350 mile round trip to do so should be able to tell if any difference,

 

[Gazz270]

update number 2,
done 409 miles today,brimmed it before i set off and just brimmed it again once home.It took 58 litres to fill which is 12.71 gallons and that works out at 32.1 mpg:bannana:,so back to normal.So whatever that sensor in the breather pipe is it makes a huge difference to mpg when its bypassed with an oil catch can.

 

[dokalj]

Bit of an update,mpg still poor.was thinking if ive done anything that might affect it,the only i could think of was i put an oil catch tank in between the breather and where it enters the pipe onto the turbo over xmas.The catch tank works great.
there is a sensor in this pipe and i wondered what it did it looks like it could possibly be a temperature sensor but why would they put one there and would it affect mpg,i am going to put it back as it should be and see what its like tomorrow,ive got a 350 mile round trip to do so should be able to tell if any difference,

Hi Gazz270,

Could you please explain this further maybe a picture? I also have a ML and would look to try this.

Sorry if this sounds silly.

Also is this mod safe and recommended?

Regards

dokalj

 

[Gazz270]

the oil catch can works really well,i had cleaned the egr before i put it on and checked a couple weeks after and the tank had about 50ml of oil in it and the egr was bone dry,the problem has been since i did this my mpg had gone down considerably,ive now put it back to standard and the mpg is now back up.
i will put some photos on at weekend when i get chance during day.i think the sensor in the breather pipe has to have the oil mist passing over it that affects the mpg.

Gareth

 

[dokalj]

Cheers Gareth!

Good to hear your ML is now healthy.

I look forward to seeing the pictures.

Thanks

dokalj

 

[Gazz270]

200SX 180SX S13 S14 Square Oil Catch Tank 9/15mm Silver on eBay (end time 20-Jan-11 10:34:56 GMT)

this is the link to the catch tank.

Gareth

 

[dokalj]

Cheers.

Regards

dokalj