I really hope someone can help me. I have a 2000 SLK 3.2 auto and recently I have been experiencing problems when I floor it between 3 / 4 000 rpm. I find I have a dead spot and sometimes it has almost cut out on me and feels like it is running on 3 cylinders. Just had a full service and have looked afterher well. Can anyone help me please?

Ben

 

Hi Ben,

CEL Check Engine Light ON?
If not see what happens when you demand max power from the car. i.e. Timed acceleration run up to max shift speeds.
CEL on now?

After the accel run get the DTC Diagnostic Codes read with an OBDII compliant scanner and lets see what the diagnostics think.

You don't mention mileage. 70k miles+? COULD BE your MAF but lets get a bit more data before lashing out.

I trust your original cutting out issue was resolved by the "K40" fix?

Stuart

 

Hi Stuart,
Thank you for your response. Firstly the millage is 112,000 on a 2000 which is high but I don’t expect it to die at this mileage.
I do not get any lights come on when the problem happens, it is as if it loses a cylinder or to when you really gun it.
I will arrange for a brain scan and let you know what the results are.
Thanks for your help mate,
Ben

P.S The last cutting out problem I had was on a different car, I changed it for that reason alone and now it has happened again, so I am not best amused!

 

112k...it should go on forever!

Just checking. Does the CEL comes on when you first turn the ignition on. Correct? OK it hasn't been disconnected / turned off.

Lets assume outcome is no codes set but this doesn't mean there won't be if the light is off. I also assume that the air filter etc have been changed at recommended change points. I don't believe for one moment these are at fault but you never know.

Any more details about when / how this first started? Could be important clues here.

Subject to the above my attention would firstly turn to an intermittent fuel supply. However it could be the ignition. (The CPS Crank Position Sensor is a known source of problem and doesn't set codes. However before going this route you need to eliminate a whole host of other possibilities unless cost is irrelevant to you.

Intermittent faults are difficult to locate.

Simplest way to eliminate the fuel pump electric supply (faulty relays, oil switch, ECU etc) is to connect a light across the pump contacts and wire this back to somewhere where you can see it in the cabin whilst you are driving and the problem occurs.
Intermittent interruption of the power supply is a real possibility?
Whilst you are at it the fuel filter should be changed if it has not been changed for 50k or so miles. IMHO these get swapped out unnecessarily but they are low cost and they do include a pressure relief valve which could be at fault but I doubt that this will be the cause.
When I changed the filters on my cars (entirely precautionary at 100k+ I was amazed just how little debris was present within and how clean the filter appeared. (I dismembered it in order to understand the working). All about how good your fuel quality is but it does eliminate certain possibilities.

Of course there could be many reasons for this problem.
The trick is to avoid replacing everything in sight!

I'll await some feedback from you before going further. Incidentally. The problem didn't start coincident with the service did it?

Stuart