Maf

coppersid · 21st October 2007, 19:46

Evening All
I hope someone can advise me on our much talked about friend ...the maf!
Yesterday I unplugged the maf and ran my tourer a few miles and did not notice any difference to when it was connected.
Today I took the plunge and removed those pesky screws ( by filing a slot in a slotted screwdriver....most pleased about that!! I also cut a slot in the plastic shroud to access the maf...thanks to advice on this site)
I cleaned the maf with the correct spray cleaner. However after replacing cleaned, still felt no tangible difference.
I also cleaned out that egr thing...it was filthy!
So what does all this mean please? Reason I did all above was slight roughness on idling (650 revs) and some flatness between 30 and 40 mph

2002 cdt conn auto hi-line. maf....Bosch

Many thanks.
Sid

pondweed · 21st October 2007, 19:56

well it sounds like the MAF is ok then! did your same flatness and idle persist with the maf unplugged too?

and did these disappear after you cleaned the EGR, or still same?

coppersid · 21st October 2007, 19:59

hi...there was no difference post cleaning of maf and egr...same rough idling but i never encountered any flat spot

JohnDotCom · 21st October 2007, 22:52

Still sounds like it could be MAF.
Where is Ron and the others when you need them?
Sleeping if they have any sense.

Keith · 21st October 2007, 23:19

if you had the Maf unplugged and the car ran the same as before then I would have left it alone cleaning it is a last resort exercise as it can often do more harm than good

pondweed · 22nd October 2007, 07:34

i guess the mext sensible question is what is your car's mileage... and has it ever had any 'major' replacements in fuel system area?

comet · 22nd October 2007, 09:38

Yes Rover Ron should be along shortly but if you already havn't used the search please give it a whirl with "MAF" in search line. The answers are all genuine.
I myself have a "roveron" mafam and pierborg maf and I will never go back to the original set up, my car was useless at standing starts and roundabouts but not now!.

Roverron · 22nd October 2007, 18:44

I'm here!

Unfortunately, disconnecting the maf is not a foolproof diagnostic technique because it only really shows a maf with a below normal signal. (which gives poor low down torque).

About 20% of mafs start to give too high a signal as they age. These don't tend to show up because low down torque isn't affected adversely, in fact it will often be very good at very low revs.
But you can have smoke at low rpm, sooty deposit on the bumper, rough idle and hesitation when you accelerate gently at low rpm plus some smoke, which clears once the turbo gets going and a detioration in mpg. All are signs of overfuelling due to too high a maf signal.

The only way to confirm this is to try another maf or PB maf + mafam or Synergy 2.

Pesky Bosch mafs!

Ron

21st October 2007, 19:46	#1
coppersid Newbie Rover 75 Tourer CDT Auto 2001 Hi-Line Join Date: Aug 2007 Location: West Yorks Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Maf Evening All I hope someone can advise me on our much talked about friend ...the maf! Yesterday I unplugged the maf and ran my tourer a few miles and did not notice any difference to when it was connected. Today I took the plunge and removed those pesky screws ( by filing a slot in a slotted screwdriver....most pleased about that!! I also cut a slot in the plastic shroud to access the maf...thanks to advice on this site) I cleaned the maf with the correct spray cleaner. However after replacing cleaned, still felt no tangible difference. I also cleaned out that egr thing...it was filthy! So what does all this mean please? Reason I did all above was slight roughness on idling (650 revs) and some flatness between 30 and 40 mph 2002 cdt conn auto hi-line. maf....Bosch Many thanks. Sid

22nd October 2007, 18:44	#8
Roverron Gets stuck in Rover Join Date: Nov 2006 Location: Tarbert Posts: 980 Thanks: 0 Thanked 19 Times in 9 Posts	I'm here! Unfortunately, disconnecting the maf is not a foolproof diagnostic technique because it only really shows a maf with a below normal signal. (which gives poor low down torque). About 20% of mafs start to give too high a signal as they age. These don't tend to show up because low down torque isn't affected adversely, in fact it will often be very good at very low revs. But you can have smoke at low rpm, sooty deposit on the bumper, rough idle and hesitation when you accelerate gently at low rpm plus some smoke, which clears once the turbo gets going and a detioration in mpg. All are signs of overfuelling due to too high a maf signal. The only way to confirm this is to try another maf or PB maf + mafam or Synergy 2. Pesky Bosch mafs! Ron __________________ [SIGPIC][/SIGPIC] Click to visit my website Ron on Twitter MyFacebook page

21st October 2007, 19:56	#2
pondweed This is my second home Waiter, Waiter! I seem to have a Roomster in my drive... Join Date: Nov 2006 Location: Sussex Posts: 3,268 Thanks: 0 Thanked 1 Time in 1 Post	well it sounds like the MAF is ok then! did your same flatness and idle persist with the maf unplugged too? and did these disappear after you cleaned the EGR, or still same?

21st October 2007, 19:59	#3
coppersid Newbie Rover 75 Tourer CDT Auto 2001 Hi-Line Join Date: Aug 2007 Location: West Yorks Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	hi...there was no difference post cleaning of maf and egr...same rough idling but i never encountered any flat spot

21st October 2007, 22:52	#4
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	Still sounds like it could be MAF. Where is Ron and the others when you need them? Sleeping if they have any sense.

21st October 2007, 23:19	#5
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	if you had the Maf unplugged and the car ran the same as before then I would have left it alone cleaning it is a last resort exercise as it can often do more harm than good

22nd October 2007, 07:34	#6
pondweed This is my second home Waiter, Waiter! I seem to have a Roomster in my drive... Join Date: Nov 2006 Location: Sussex Posts: 3,268 Thanks: 0 Thanked 1 Time in 1 Post	i guess the mext sensible question is what is your car's mileage... and has it ever had any 'major' replacements in fuel system area?

22nd October 2007, 09:38	#7
comet Avid contributor CDTConnSE Wreg 102000mls Join Date: Nov 2006 Location: Grappenhall. Cheshire Posts: 105 Thanks: 3 Thanked 15 Times in 1 Post	Yes Rover Ron should be along shortly but if you already havn't used the search please give it a whirl with "MAF" in search line. The answers are all genuine. I myself have a "roveron" mafam and pierborg maf and I will never go back to the original set up, my car was useless at standing starts and roundabouts but not now!.