M272 E30 (CLK280) Hesitation when cold

[DelDrew]

Hi everyone,

So I'm a newbie here and been pouring over the various threads picking up loads of really useful information.

I've just bought a 2007 CLK280 convertible as a 2nd car. It was a bargain price but it does need a little TLC!

So, the first issue that I'd love some advice on, is a hesitation when cold.

Scenario is that I start the car in the morning (this only happens in the morning). Can let it warm up or drive straight off, it doesn't seem to matter, but for the first mile or so of my journey when I try to pull away, usually at a junction, there's just no power. This can be a little nerve-wracking if I'm trying to pull into a busy road from a side road! I push the throttle down and nothing happens. Eventually once I've pressed the pedal at least half way, the car launches off at a rate of knots! In the damp or wet, this usually triggers the traction control

The engine doesn't appear to run roughly and general gear changes seem smooth.

So, looking at threads, I've struggled to find one that describes this issue.

I'm having the gearbox megaflushed at a local MB Specialist for two reasons, firstly its been out of the MB service network for 6 years and it appears the 40k mileage gearbox service hasn't been completed for 80k and the car is now on 108k, so potentially 68k miles overdue for a service. Secondly, I had picked up a thread that suggested a gearbox service and mega flush might clear hesitation issues.

However, the Indy has said that he thinks my problem lies with the throttle body.
I thought that, if this was the case, it would throw up the engine management light, but the Indy says no.

Assuming he is right, I have three options.
Firstly, pay him to fit a new one (£670+fitting) - Eurocarparts price
Secondly, I send mine off to get it reconditioned, do the strip down and instal myself (£250)
Thirdly, pick up a used but working/tested throttle body from eBay and install it (c.£25)

If I remove the throttle body myself, is there any recoding needed to install the new or reconditioned one or are throttle bodies plug and play? I don't want to end up with a dead car on my driveway.

Are there likely to be any other issues that could give me the problem I have described or do you all agree with my indy? And, if so, are options 2 or 3 doable on a driveway without being able to sort out any pairing issues that might be generated by unplugging the throttle body and plugging in a different one or even the original if it has been reconditioned???

Before I do anything though, I will try a can of throttle body cleaning spray!

Sorry for the big post, just wanted to try to give everyone as much info as possible.

Thanks in advance!

Del

 

[PobodY]

I was just going to suggest starting with a can of throttled body cleaner.

Is the hesitation weather dependant? I'm just wondering if it's something like an engine coolant sensor not recognising the engine isn't warmed-up. I don't know about MB, but on my other car the ECU and gauges have separate sensors.

Have you got summer tyres installed? The ESP isn't quite so active with winters installed.

 

[JamesG66]

My M272 engine used to do something similar, in that it wouldn't idle smoothly from cold for the first 20 secs or so. I cleaned the MAF and also replaced the seal between the airbox and the MAF as it had split. This cured it, so definitely clean things up first.

Regarding the gearbox, I would be careful about any treatment that involves "flushing" as I've read a few horror stories of that causing debris to dislodge and doing more damage. A simple drain and refill was what I opted for when I did it recently and my local MB dealer were only £20 more than the local Indy so I used them. £275 if I recall.

 

[DelDrew]

I was just going to suggest starting with a can of throttled body cleaner.

Is the hesitation weather dependant? I'm just wondering if it's something like an engine coolant sensor not recognising the engine isn't warmed-up. I don't know about MB, but on my other car the ECU and gauges have separate sensors.

Have you got summer tyres installed? The ESP isn't quite so active with winters installed.

Haha, yes I thought I'd better add that in!

I can't say for sure whether the problem is weather dependent or not as I've not had the car very long. It is possible that it is worse the colder the ambient temperature is.

I don't have winter tyres fitted, what are good ones on the market?

Thanks

 

[DelDrew]

My M272 engine used to do something similar, in that it wouldn't idle smoothly from cold for the first 20 secs or so. I cleaned the MAF and also replaced the seal between the airbox and the MAF as it had split. This cured it, so definitely clean things up first.

Regarding the gearbox, I would be careful about any treatment that involves "flushing" as I've read a few horror stories of that causing debris to dislodge and doing more damage. A simple drain and refill was what I opted for when I did it recently and my local MB dealer were only £20 more than the local Indy so I used them. £275 if I recall.

I'll take a look at the MAF/airbox seal, thanks for the heads-up on that. I've seen that come up in several threads, wasn't 100% the symptoms matched mine, but I won't discount it.

I hadn't heard about issues with gearbox flushing. Its a bit late now, guess I'll just have to keep my fingers crossed that I don't get more problems! I do need to check MB prices for things though and not just assume they're going to be ludicrously expensive with everything. Sometimes they can be surprisingly competitive and I should credit them with that.

Thanks for your advice

 

[DelDrew]

Update

Not much to report. I drove home from the Indy this afternoon. They reported that the transmission service and flush was complete and that they had reset all the adaptive learning in the gearbox memory - which apparently will take 600-800 miles to re-learn.
Tomorrow morning we will find out whether this has resolved the issue or not. I will let you know!

 

[rifiki]

I just don't this, gear box to learn my my driving style. I drive according to road/traffic conditions, I have eyes not the gearbox !!!!

 

[MancMike]

The ECU and TCU adapt to your current "mood".

If you start belting it around, frequently flooring it through the kick-down and accelerating until it shifts just below the redline, then it'll start hanging onto gears longer, you'll experience engine braking when lifting off as it keeps the low gear incase you're about to floor it again, and downshifting further to give the most acceleration it can, even if that puts the engine at 5000+ and it's roaring.

Then you start taking it easy and it'll start shifting at the first appropriate time and only shift down a gear or two if you put your foot down a bit. In the "excited" state, depressing your foot from say 20% travel to 30% travel might drop a gear, whereas in the sedate state, it'll keep the current gear and just let your speed gently creep up.

I'm not sure about 800 miles, it constantly adapts, it can go from sedate to eager and back on my 10 mile commute.

 

[grober]

Your car will probably have an electronic throttle?? If so there are two components to this--- the throttle pedal assembly and the throttle body as mentioned. A problem with either would give you the symptoms you describe.

 

[DelDrew]

Thanks Grober, I'm sure you are right. Unfortunately, having got the car back from the Indy yesterday, the water pump went this morning so it's been recovered back to them. The hesitation and general gear changing is far better follow the gearbox service and flush but the hesitation hasn't been entirely cured.
I'm going to follow the throttle body reset procedure when I get the car back and try that, if there's still a problem, I'll get a can of cleaner and try that. Failing that I'll be looking at replacing or reconditioning the throttle body.
I'll keep you posted!


Sent from my iPhone using Tapatalk Pro

 

[DelDrew]

Seems sorted now!

Hi all,

Thanks again for everyone's suggestions. I think I've resolved the problem now.

I removed the MAF sensor and used CRC MAF cleaner on it and I removed the throttle body and used a throttle body cleaner on it.

The hesitation and rough idle have completely gone now and she purrs like a kitten!

Cheers all! :bannana:

Del

 

[rifiki]

i-CONICA The TV program 'building a super car' it would appear the new Roller's gearbox has eyes!!

 

[MancMike]

Yep, I saw that, with the "looking ahead" GPS stuff to know in advance what gears you'll likely need, etc.