Help needed LIMP MODE

[chrisquay]

The problem I’m faced with is that my car has a flat spot whenever I try to accelerate and has very little power most of the other time, I had a diagnostics from someone out of the local paper who informed me that it was the 02 sensor which I duly had changed which didn’t make a sred of difference. I then tried my local mechanic who after running a diagnostics test the it was acam sensor as the reading were too varied. H changed the cam sensor which again made no difference. He thought maybe sticking valve. I finally bit the bullet and took the car to my local Mercedes dealer

They ran diagnostics and also checked the car out and informed that they strongly suspected that the fault causing the flat spot was a fault to the airmass sensor due to it being contaminated by oil. they suspected the valves were blocked causing contamination through the inlet manifold.

The advive and quote I was given was to have the valves Unblocked and the airmass replaced at a cost of £689 inc.this cost was based on 5 hours labour plus parts I asked the technician how sure he was that this would cure the fault and he replied Im pretty sure as your sensor has oil over it.. I could just replace that and your car would run ok for a couple of weeks but then it would revert back to limp mode however he couldn’t guarantee that this would cure the fault

At nearly £700.00 I’m worried at paying that sort of money as a gamble. The car is a 1999 230CLK Kompressor which has done 70,000 it runs fine on tick over just when I start to move. It has also just stated to jump when it moves into 3rd.

Any advise greatly arpeactied as Im in to totally despair at having already spent £££ and don’t seem to have got anywhere


regards
Chris

 

[Andrew Rymer]

Good luck !!!!

As you can see from my posts it has cost a ****** fortune up to now to try and "cure" limp mode.

Going to take mine to MBTech in Warrington.

 

[television]

If you have oil going into the MAF then the cam adjuster seal has gone and should be replaced along with the wiring loom for this part.

I am shocked at the poor diagnosis that you have had done, and very expensive.

As a rule what happens is this,, the seal leaks oil into the wiring and this leaks into the MAF, the oil then gets burnt in the engine, and this signals the O2 sensor to shift from its stored setting (engine lamp on now) to try and compensate.


Your new MAF £147) will wash out OK, and sorry I do not think much of who has been doing this expensive work.

Welcome to the MB forum

 

[jimsinessex]

At nearly £700.00 I’m worried at paying that sort of money as a gamble. The car is a 1999 230CLK Kompressor which has done 70,000 it runs fine on tick over just when I start to move. It has also just stated to jump when it moves into 3rd.

Any advise greatly arpeactied as Im in to totally despair at having already spent £££ and don’t seem to have got anywhere


regards
Chris

Open the air filter and check if oil is present AFTER the filter. If it is then it is not the Cam Adjuster Magnet but the dreaded "oil in air intake" problem which can happen at 70,000 miles onwards in your car.

Read the thread "oil in air filter" started by Balal and the DIY by JamesMc and all will be revealed.

The quote is about right as the problem requires the low load to upper part load crankcase breather system underneath the inlet manifold to be renewed. Parts are approx £20 but 4 1/2 hrs labour is required.

PM me by all means as I spent a lot of time tracking down the source of this contamination.

jim

 

[jberks]

Your quote sounds about right based on what they say it needs but do be aware that an indie specialist should be able to do the work a lot cheaper. The dealer is quoting 5hrs at £100 per hour. An indie with the same kit and experience should be around half that, saving at least £250 on the above quote. The second opinion may be useful too!

Flat spot does sound MAF/O2 sensor related (my E240 did the same and was cured by replacing them) but in your case this is a symptom and it's the original cause that is the concern.