CLK230K with flat spot/lack of kickdown

[lauzie_b]

I've got (well my dad but i drive it too) a X reg (2000) clk230K.

Its got a flat spot in the acceleration at around 2-3000 revs. The kickdown also has a real lag before it kicks in. Its auto, but the gears dont seem to be changing at the right time and it just feels really pokey and slow at the moment.

Its got £126,000 on the clock and we've owned it for 8 years. Its not been driven really hard and its always been serviced and well maintained (serviced at private merc specialist garages)

Can anyone shed some light on possible problems i can look into?

Is there a software for reading faults like you have with VW's (vagcom)?

Thanks

Laura

 

[jamesmc]

By all means gets the fault codes read.. your local independent MB specialist should be able to do that for you. The codes may give you a clue as the fault but MAF problems may not show. Read on......

Firstly check that the Automatic transmission fluid is at it's correct level. There is no dipstick fitted so either make one (instructions in the DIY section) or buy one. There are instructions in the DIY section on checking Automatic gearboxes. Yours will more than likely be the 722.6 five speed box.

Gearbox oil level OK?
Do a search on MAF. That is the next thing I would look at. Is it really oily? If so look at the DIY section for stopping oil reaching the MAF.
This involves changing out most of the lower part breather system locate under the inlet manifold. It's a manifold off job plus you'll need to clean out the inlet pipework including the intercooler.
Then replace the MAF with a new one (or at least new MAF insert).

If MAF can be discounted and the lower part breather system is working as it should plus you still have the same problem, then I would look at replacing the Secondary air injection system non return valve (This is a mechanical one way valve that injects air into the exhaust system to burn off any unburned fuel before it reaches the cats/atmosphere. You need to remove the air box to get at it. You'll also need a slim open ended 27mm spanner to remove replace the valve. It's located near the exhaust manifold. Black rubber pipe fitted to one end with the other end screwed into a stainless steel fitting/pipe. Not to be mistaken with the Air recirculation valve which is fitted to the airbox itself.

All of the above are cheap fixes except for the MAF replacement. MB will charge you a mint. Sourcing one from a Bosch service agent will be cheaper. Do not buy a cheap one from eBay (35-55 quid or thereabouts). An eBay unit will either not do the job or will fail in short order.

 

[jibcl500]

MAF

jib

 

[Acid@MSL]

Air mass sensor common problem

 

[Acid@MSL]

get a bosch one from GSF or Eurocarparts the cheap ones are rubbish

acid

 

[jamesmc]

Air mass sensor common problem

Yes it is..... but in a case like this, not always the root, and only, cause.
For example, no point in just changing the MAF if the original is soaked in engine oil. Equally the secondary air injection (non return) valve can produce similar symptoms and therefore changing the MAF might not see the problem go away. It most probably will, but it's good for the OP to see possible options rather than just reading MAF, fitting a new one, and then wondering why the car is still not much better.

 

[jimsinessex]

Almost certainly the MAF and at that mileage most likely to be caused by oil in the air intake. Take cover off the air filter and see if oil is present AFTER the filter at the point where the rocker cover oil separator pipe enters the chamber. Cleaning the MAF may keep you going in the short term but the root cause needs to be tackled or the money spent on a new MAF sensor will be wasted.

For further information see thread on "Oil in air intake" by Balal and the DIY by Jamesmc.

Jim

 

[television]

MAFs also from here and Bosch service sensors

http://www.airmassmeters.com/

 

[jamesmc]

.........and here on eBay.

http://stores.ebay.co.uk/carpartsberlin
These are New Genuine Bosch parts with a two year warranty
They will post anywhere.
I used them a year or so back.

Usual eBay warning applies.... do not be tempted by a (non original) cheap replacement often seen on eBay for around 50 quid. It will all end in tears!

 

[moosehead]

Sounds like exactly the same symptoms we had with our 1999 SLK230. It had the original MAF as we've owned the car for 9 years. I replaced it earlier this week with a genuine Bosch unit (£149) and the transformation is amazing - pulls like a train, smooth gear changes, improved idle, etc. The sensors must degrade over a period of time as the performance has slowly tailed off.

I did try cleaning the old sensor a couple of weeks back. There was no oil contamination and it had absolutley no effect.

 

[Dringo]

Hmmm... I am researching these pesky MAF issues.
Our 2000 CLK 320 Cabriolet just started being severely rev-limited if any load is offered on the accelerator. Once the limiting kicks in, its barely driveable but resets on the ignition.

I checked my MAF unit and it looks clean, and not oily. Air filter is pretty clean too. I am hoping its just that the MAF has deterioated and a new one will fix it.

So far, Merc price is £219, and www.maf-shop.com is only a little better at 149 Euros for a Loewe make.

Any ideas where else to try (not ebay).
-jd

 

[rpe2]

try www.eurocarparts.com

 

[vijilants]

Hmmm... I am researching these pesky MAF issues.
Our 2000 CLK 320 Cabriolet just started being severely rev-limited if any load is offered on the accelerator. Once the limiting kicks in, its barely driveable but resets on the ignition.

I checked my MAF unit and it looks clean, and not oily. Air filter is pretty clean too. I am hoping its just that the MAF has deterioated and a new one will fix it.

So far, Merc price is £219, and www.maf-shop.com is only a little better at 149 Euros for a Loewe make.

Any ideas where else to try (not ebay).
-jd

Get a Bosch unit and save yourself a lot of hassle. Get the Bosch part number from your existing unit and ring around the Bosch agents or try Euro Car parts,

 

[Dringo]

Exactly - got it from eurocarparts.com, although as it was after 1pm it didn't turn up today so have to wait a bit longer to see.
Cost £103, incl VAT and Delivery. Its a Bosch.

This compares to a bill for over £300 5 years ago when the same thing failed on my C240TE Sport, 5 years old at the time and booked into a Dealer to fix. Ouch.

I hope it works.

 

[Dringo]

Worked fine btw, when it turned up, and took 5 mins to fit it.