First 2 Minutes 1999 C200

[NSquirrel]

Strange problem others may be able to help me with. When starting from cold my C200 (WDB202) feels almost choked for the first 2 minutes. Almost no acceleration and a max speed of about 20 mph. After about 1 mile it starts to regain acceleration and is fine and perfectly normal for the rest of the day however many stops and starts. Next day, when the engine in completely cold, it is slow again.

If it had a carb, I would suspect the choke not working correctly, but my knowledge of injectors, etc. is limited. I've checked the air filters, etc., but then if they were blocked I wouldn't expect the roughly 2 minutes period; I would expect it to be much longer.

The car has been driven from new by me; has about 81K on the clock and has been regularly serviced by MB.

Any suggestions would be gratefully received.
TIA

(BTW I have tried a search here, but did not find anything obvious.)

 

[NW_Merc]

It needs to be put onto STAR diagnostics as the fault codes would be registered on the ECU helping to pinpoint the problem.

It could be any of:
1. Mass Air Flow (MAF) meter not working
2. HT leads
3. Coil packs
4. Throttle body

Without knowing exactly you will be unnecessarily spending money which may not fix the issue.

 

[jefrs]

I know what you mean about carburettors.

You've had this car from new and it has always been MB serviced. First thought is aim the car at your garage people.

I'm going to go out of the box here, it's a 99 so the right age, and suggest you check all the earthing points in the engine bay (brown wires bolted to bodywork, some hidden), and then the battery for low voltage.
The first will exacerbate the second. Poor earthing means low voltage. Poor battery will be most obvious first thing in the morning.

 

[Dieselman]

Possible temp sensor of MAF problem.

 

[NSquirrel]

Thanks for the comments above. I have car booked in for the annual service, so I will see what they come up with...

 

[NSquirrel]

I meant to post back the solution earlier... It was a dirty MAF sensor, which I found before the garage. I looked at the sensor wire with a magnifying glass and there was a thin film of oil or similar on it and a few fibres, which looked like they came from the air filter. £3.99 of cleaning fluid from Halfords and I was away. Something that was really helpful and hence may help others was a pdf of how to remove and clean the MAF. This came from MAF DIY PICTORIAL: replacing/cleaning - Benzworld.org - Mercedes-Benz Discussion Forum The pdf file itself is at http://www.benzworld.org/forums/att...-maf-diy-pictorial-replacing-cleaning-maf.pdf)

 

[NSquirrel]

I meant to post back the solution earlier... It was a dirty MAF sensor, which I found before the garage. I looked at the sensor wire with a magnifying glass and there was a thin film of oil or similar on it and a few fibres, which looked like they came from the air filter. £3.99 of cleaning fluid from Halfords and I was away.

Something that was really helpful and hence may help others was a pdf of how to remove and clean the MAF. This came from
MAF DIY PICTORIAL: replacing/cleaning - Benzworld.org - Mercedes-Benz Discussion Forum

The pdf file itself is at http://www.benzworld.org/forums/att...-maf-diy-pictorial-replacing-cleaning-maf.pdf)