C55 wants to stall and sometimes it does.

[brucemillar]

Friends

My C55 is laid up for the winter and kept garaged and healthy on a maintenance battery charger etc.

Yesterday I removed the air box to clean it and fit new filters.

On refitting it and starting the car!! The car runs and ticks over fine. Then when I blip the throttle and let the revs drop....They drop too low and the engine either stalls or surges and recovers. I also now have an eml that clears if I disconnect the battery.

A cursory check by removing the air box reveals no obvious issues - pipes off etc. I have noticed that the MAF appears to be loose and I think that the clip that should hold it to the engine is broken? I can't really tell without another car to compare?

• If the MAF is not sealing to the air box? Would the car behave like this?
• Should I be able to wiggle the MAF about in a way that it may not make a good seal with the air box? Or, should it be rigid in it's mounting?
  

I drove it up and down the road and when coming to a halt (everything seemed fine apart from the eml) the car stalled, restarting first turn of the key.

 

[Auto-mobile]

When you pushed the airbox back on did you dislodge the elbow going onto the throttle body? You would be letting in unmetered air then.

 

[brucemillar]

Thank you. That is entirely possible. Where should I be looking for the elbow? Is it under-near the MAF?

 

[logman]

Hi I was informed that after change of air filters on e55/e63 star has to reset engine management system however I don't think this would cause cutting out of engine

 

[Auto-mobile]

Thank you. That is entirely possible. Where should I be looking for the elbow? Is it under-near the MAF?

Yes under the maf.

 

[brucemillar]

Yes under the maf.

Had a look today. I see one rubber elbow on the drivers side under the MAF. That is connected nice and tight. Plugging it in shows a MAF error. So MAF may be bad? I will unplug it and see what happens.

 

[Auto-mobile]

Maybe didn't like being disturbed, Rev it in park, does it Hold back? If it does I'd change the maf.

 

[brucemillar]

Maybe didn't like being disturbed, Rev it in park, does it Hold back? If it does I'd change the maf.

Hi. It revs well if you blip it. But if you lift it wants stall or does stall as the revs drop too low. It will idle just fine. Still has EMl

 

[rorf]

MAF should not wiggle about - many of the rubber pipes, hoses and plastic parts are subjected to high heat and so over the years it is inevitable that seals will not be doing their job.

This applies to vacuum pipes as well.

You need to trace all air and vacuum connections and check their integrity.

 

[Petrol Pete]

Hi I was informed that after change of air filters on e55/e63 star has to reset engine management system however I don't think this would cause cutting out of engine

I can understand why one might use Star to 'tell' the car that its air filters have been changed but I can't see how not telling it would make it stall on idling. I am interested in this thread as I am about to change the air filters on my C55.

 

[brucemillar]

Plugged the car in yesterday to iCarsoft and it shows MAF low voltage. I unplugged the MAF electrical connector and this made NO difference to the issue. That suggests that the MAF itself, is the culprit. I will have a try with some cleaner. If that fails I will replace he MAF with a good branded part.

There are no other obvious vac leaks. Tested with some damp start.

 

[brucemillar]

Friends

Can anybody please advise if the plastic clamp that holds the MAF to the engine is available as a part please?

As above one of the retaining fingers is missing on mine allowing the MAF to move. I am not sure that it is then able to correctly locate and seal to the air box, when it is fitted back on.

The car is a W203 (2004 vintage) C55 AMG Estate.


Many thanks.

 

[brucemillar]

The part # is: A112 141 03 40. Priced £2.40 from Mercedes Germany.

 

[brucemillar]

Update:

I fitted a new MAF clip and the MAF is now nice, snug and tight to the air box and engine inlet manifold.

I am still getting OBD Code = P0102 and an EML light.

I can re-set both, but they return as soon as I switch the engine or within a few seconds of switch on. The engine idles fine but wants to stall if you blip the throttle - the revs go up as they should but then she bogs down and tries to catch or stall.

Any other clues or suggestions before I shell out on a new MAF?

 

[brucemillar]

Gentle bump.

Sent from my iPhone using MBClub UK

 

[WG M-B]

Sounds like an air leak

 

[brucemillar]

Folks

I need some help here please....

The rubber breather/Vac pipe that runs under the MAF and crosses from one bank (rocker cover height) to the other (I think) with an elbow, directly under and in front of the MAF. Could somebody tell me please:

a) Is it one pipe or two?
b) What the part number(s) is please.

This is the only pipe that I can see at the MAF end (rear) of the engine, that looks like a vacuum or breather pipe. It sits in a horseshoe on the MAF retaining clip. I haven't pulled it right out yet to inspect it. But it is, as old as the car so probably warrants replacing.

Are there any other vac hose(s), that I should be looking at, that may give me a MAF error and symptoms? I see another slightly fatter hose that runs across the front of the block on the top, under the air box. That looks new and not split.

 

[Auto-mobile]

Can't think off the top of my head, the only pipe round there on my c43 is the brake booster pipe but you would either hear that leaking or have a hard brake pedal, have you tried spraying brake cleaner or wd40 with the engine running and the airbox on? See if the rpm change when sprayed.

 

[brucemillar]

Can't think off the top of my head, the only pipe round there on my c43 is the brake booster pipe but you would either hear that leaking or have a hard brake pedal, have you tried spraying brake cleaner or wd40 with the engine running and the airbox on? See if the rpm change when sprayed.

I'm going more from Wayne's comment "sounds like an air leak". That is the only pipe(s) that I can see there. Yes I tried the damp start test. But with the C55 when the air box is there is no room even allowing for overspray from the can. I am loathed to spend £250 on a MAF to find it was a leaky £5.00 pipe ^)

 

[Lyserman]

There are 4 pipes and a connector in that area.
They are the part load and full load crankcase ventilation pipes.
Part numbers are:
A1120180482 Full Load £8.75
A1120180182 Part Load £6.97
A1120180282 Part Load £4.32
A1120180382 Part Load £6.97

[URL=http://s250.photobucket.com/user/lyserman/media/C55%20Vent.jpg.html][/URL]

Hope that is of some use.

Tony