MAF Issues

[Larpy]

Hi
This is my first post so please excuse any technical ignorance. I have a 2001C Class 2 litre Kompressor, the issue i have started about four months ago, the engine management light came on and the performance of the car deterioated dramatically. I took the car to my local Merc stealer who wanted to rob me of £700 before they even booked the car in saying that the air mass filter needed changing. I changed this myself, after purchasing a new Bosch one. The problem still persists, i have had the car serviced by an independant who has advised me that on this model oil some how gets into the wiring loom and contaminates the ECU, which then triggers the engine management light. When the computer is hooked up to the car the vault comes up as an air blockage. I have just read the article by Parrot of Doom in the DIY section and am seriously considering giving it a go, can any one give me any hints, tips, info. Thanks in advance.

 

[television]

Hello and welcome to the forum.

The seal to the camshaft adjuster has gone allowing oil to travel through the wiring harness, through the MAF and into the engine where it gets burnt in the engine, the O2 sensor picks this up and tries to adjust the fuel mixture, and this turns on the lamp.

A new seal and short harness is required, the MAF and any ECU will wash clean.

Could you fix it yourself or would you use an indie

 

[Larpy]

Hi Malcolm

Thanks for the info, I think i will get the indi to do this work, its the wifes car, I drive a landrover and on occasions this requires lump hammer and brute force, i do not think Mr Benz envisaged some one taking said tool and attitude to a Merc.

The indi has quoted me £250 for the job all in. If this is completed i presume the problem will be rectified?

 

[television]

Hi Malcolm

Thanks for the info, I think i will get the indi to do this work, its the wifes car, I drive a landrover and on occasions this requires lump hammer and brute force, i do not think Mr Benz envisaged some one taking said tool and attitude to a Merc.

The indi has quoted me £250 for the job all in. If this is completed i presume the problem will be rectified?

Thats OK at that price, and that should be the end of it, going into the limp home that is

 

[MB TECH WARRINGTON]

Hello and welcome to the forum.

The seal to the camshaft adjuster has gone allowing oil to travel through the wiring harness, through the MAF and into the engine where it gets burnt in the engine, the O2 sensor picks this up and tries to adjust the fuel mixture, and this turns on the lamp.

A new seal and short harness is required, the MAF and any ECU will wash clean.

Could you fix it yourself or would you use an indie

malcolm, when the camshaft adjuster leaks oil it runs to the electrical plugs, to the ecu and to x connectors etc, it does not enter the intake system through this fault,

the oil entering the intake and contaminating the airmass is a different fault due to engine breathers/ventilation etc,

this fault of oil entering the intake system is NOT cured by the mods you have mentioned, the oil will still contaminate the airmass.

 

[television]

Yes the oil goes into the ECU and I have washed 2 out for people here. it does work its way down to the maf in bad cases via the loom hence the oily deposit in the MAF that re appear for sometime unless the harness is replaced

 

[Larpy]

So does this mean that i will need to check breather pipes as well as replace the seal? I remember a 318 BMW i had that did the same, the fault registered as blocked air flow, and upon checking a breather pipe had rotted away. This also made the cars performance very poor, ie high fuel consumption, poor pick up ect.

 

[television]

No you should not have a breather problem, check the wires and plug where it plugs into the MAF, if the plug or wires are oily then the oil has run down from the ECU.


It is a very odd thing with this fault. oil in itself is very high in terms of electrical resistance, in fact nothing can be measured with probes and an ohm meter, probably due to the molecule structure of oils.

We know that oil in the ECU can turn the engine lamp on, but how, I did a test on a working skybox and poured oil all over it, and it still worked OK, these boxes contain 1000 more complicated circuits than any ECU, also the huge transformers on the National grid, that run at 660,000 volts that drop the voltage down to 440,000 and so on are all oil filled

This is still an unsolved mystery

 

[Larpy]

Thanks, you have been a great help.