MAF How do I remove & clean it?
03-09-2009, 04:07 AM
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MAF How do I remove & clean it?
Hi all.
I have an ML270CDi (02). It has the lack of power at speed problem and no kickdown when about to overtake etc. It runs great the rest of the time & shifts through all the gears as expected. Idle is nice & smooth. I can pull away fast but when at around 40mph it levels out and with pedal to the floor it refuses to go any faster or drop down a gear. Instead it seems to start slowing down until I pull the throttle back and ease it very slowly back down again. Speed then creeps up very slowly to around 80mph & stays there.
I have changed the air filter, no difference and I have reset the ECU - just got better on the short drives. I got these tips from here after searching for hours.
I now want to take off the MAF & clean it. By the way this has been unplugged & made no difference to running. Can anyone help with pics or diags of best way to remove & how to clean it without breaking it please?
I have an ML270CDi (02). It has the lack of power at speed problem and no kickdown when about to overtake etc. It runs great the rest of the time & shifts through all the gears as expected. Idle is nice & smooth. I can pull away fast but when at around 40mph it levels out and with pedal to the floor it refuses to go any faster or drop down a gear. Instead it seems to start slowing down until I pull the throttle back and ease it very slowly back down again. Speed then creeps up very slowly to around 80mph & stays there.
I have changed the air filter, no difference and I have reset the ECU - just got better on the short drives. I got these tips from here after searching for hours.
I now want to take off the MAF & clean it. By the way this has been unplugged & made no difference to running. Can anyone help with pics or diags of best way to remove & how to clean it without breaking it please?
03-09-2009, 04:17 AM
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190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
The MAF can cause problems on the 270CDI, but cleaning won't help, it would need to be replaced if it is at fault. Unpluging it won't help you diagnose it unfortunately.
Other casues may be the boost pressure sensor, blocked cat/exhaust (most common), leaking boost pressure transducer (not common), or a large air leak in the intake from either a split hose of leaking intake manifold.
I would suggest you get all current fault codes cleared and you have entered some by removing the MAF. Drive it until if looses power and then rescan for codes.
Does the engine sound like alot of air is escaping when accelerating? Does it have power when initially started then looses it after a minute or 2?
No power after an immediate restart is likely to either be boost pressure sensor or MAF. Power then it looses it after first heavy acceleration sounds more like an air leak, or blockage but it can still be both of the above.
Other casues may be the boost pressure sensor, blocked cat/exhaust (most common), leaking boost pressure transducer (not common), or a large air leak in the intake from either a split hose of leaking intake manifold.
I would suggest you get all current fault codes cleared and you have entered some by removing the MAF. Drive it until if looses power and then rescan for codes.
Does the engine sound like alot of air is escaping when accelerating? Does it have power when initially started then looses it after a minute or 2?
No power after an immediate restart is likely to either be boost pressure sensor or MAF. Power then it looses it after first heavy acceleration sounds more like an air leak, or blockage but it can still be both of the above.
03-09-2009, 05:52 AM
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Thanks Ausmbtech. I will get the codes cleared and a rescan.
There is definitely no sound of air escaping at any time, but it does lose power after heavy acceleration not immediately on restart.
Something I forgot to mention (sorry), the preglow lamp re-lights up after start. Sequence is I turn ignition, lamp goes out (as it should), I start car, pull away, lamp comes on again (no change at all in driving response) stays on for half a mile or less, then goes out. Is this related to my posted problem do you think, or is it separate?
There is definitely no sound of air escaping at any time, but it does lose power after heavy acceleration not immediately on restart.
Something I forgot to mention (sorry), the preglow lamp re-lights up after start. Sequence is I turn ignition, lamp goes out (as it should), I start car, pull away, lamp comes on again (no change at all in driving response) stays on for half a mile or less, then goes out. Is this related to my posted problem do you think, or is it separate?
03-09-2009, 07:27 AM
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190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
The glow plug light will be totally unrelated to the power loss, be careful taking on the glow plug replacement, the glow plugs are highly likely to break when you try to replace them. Don't attempt it unless you are prepared to have the vehicle off the road for a few unexpected extra days incase you need to drill them out. always replace all 5 together.
As for the low power, get back to us when you have some codes to go off.
As for the low power, get back to us when you have some codes to go off.
03-12-2009, 06:54 PM
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Great news for me! It was the MAF. Took it to my guy with his code reader and the MAF code would not go away. Removed the MAF and the tiny wire was not visible, put in the new MAF & it goes like a rocket (the car not the MAF:-))
Thanks for your help. I really appreciate it.
Now I just need to find out how to fix the rear door not locking on the central locking & my ML will be perfect - well almost perfect :-)
Thanks for your help. I really appreciate it.
Now I just need to find out how to fix the rear door not locking on the central locking & my ML will be perfect - well almost perfect :-)
