2003 clk200komp cabrio erratic idle/ hesitation

[paulmann]

hi guys
first posting on the forum
a am member of a couple of other makes of car forums in the uk and find they are amazingly good and helpful, no doubt the same or even better on this site

i give you a little history of the events on this car
2003 100000km
basically in the first 9 years nothing to remark
i did just regular servicing ( always do it myself , bit of a fanatic for cars )
engine light on , take to mb star check and say maf is out of range
i check up google and see that the little breather jets can get blocked in town driving ( wifes car 100 pct city ) and foul up the maf with oily gunk
get the guy to take off the inlet tracts and clean out the jets
engine light off
about 6 months ago engine light came on and indicated low voltage
i went the cheap route and changed the battery as a first step and all was well for a couple of weeks and then the light came on again and the car died mentioning alternator failure
towed to the electrical garage where they replaced the alternator
engine light out and running better
engine light on again mentioning maf sensor bad, cleaned with brake cleaner and qtips
works ok or a few weeks
then engine light on again same problem
buy aftermarket maf and fit
engine light off
now i have got the engine hunting at idle and missing/ poor response to power request from idle to 1500 rpm, particularly bad when not fully warm
before you ask the fuel filter is also recently changed ( really expensive )
my wife is getting p-----d with the car and is about to give up
i find that a pity as basically its a good vehicle
any ideas of what to check next?
regs paulmann

 

[streethawk]

hi guys
first posting on the forum
a am member of a couple of other makes of car forums in the uk and find they are amazingly good and helpful, no doubt the same or even better on this site

i give you a little history of the events on this car
2003 100000km
basically in the first 9 years nothing to remark
i did just regular servicing ( always do it myself , bit of a fanatic for cars )
engine light on , take to mb star check and say maf is out of range
i check up google and see that the little breather jets can get blocked in town driving ( wifes car 100 pct city ) and foul up the maf with oily gunk
get the guy to take off the inlet tracts and clean out the jets
engine light off
about 6 months ago engine light came on and indicated low voltage
i went the cheap route and changed the battery as a first step and all was well for a couple of weeks and then the light came on again and the car died mentioning alternator failure
towed to the electrical garage where they replaced the alternator
engine light out and running better
engine light on again mentioning maf sensor bad, cleaned with brake cleaner and qtips
works ok or a few weeks
then engine light on again same problem
buy aftermarket maf and fit
engine light off
now i have got the engine hunting at idle and missing/ poor response to power request from idle to 1500 rpm, particularly bad when not fully warm
before you ask the fuel filter is also recently changed ( really expensive )
my wife is getting p-----d with the car and is about to give up
i find that a pity as basically its a good vehicle
any ideas of what to check next?
regs paulmann

Hi aftermarket maf is no good. Always replace with genuine Bosch maf as the cheap ones don't last. That's what it sounds like. They also don't like being cleaned! That said I did mine and alls well but it is brand new. Only got oily because after I'd done all the same work as you, I think still had residual oil in supercharger that got on maf again. Cleaned all intercooler etc so must of been oil in charger. Maybe another star session before you do anything.

 

[paulmann]

hi streethawk
indeed i have read that non oem maf can be dicky, i mayh re- try my cleaned up mb one again, to buy a oem one is very very costly
also i read that non bosch alternator can also cause issues at low rpm
the one fitted by the garage has no sticker on the body but says huco on the brushbox
any seconds on this being part of the issue?
regs paulmann

 

[streethawk]

hi streethawk
indeed i have read that non oem maf can be dicky, i mayh re- try my cleaned up mb one again, to buy a oem one is very very costly
also i read that non bosch alternator can also cause issues at low rpm
the one fitted by the garage has no sticker on the body but says huco on the brushbox
any seconds on this being part of the issue?
regs paulmann

Think a go on a star is the way forward so you don't keep throwing money at it. Mafs don't normally show up on star and it can point to other things like actuator flap etc. Check to see if you have oil in loom were the cam magnet is too as this could cause problems.