Cold - Jerking/Bucking

[buzzc1989]

Good evening all,
I'm new to the forum and looking forward to having a good read through.

I have a problem with my 2004 (54) w203 c220 cdi auto saloon. The problem seems to be worse the colder the weather is. Once the engine is up to temperature the bucking goes away and the engine seems to be quite smooth. There are a few things I want to list as possible symptoms.

1. Intermittent fluctuating idle (needle moves +/- 50 rpm) when engine is under load I.e putting car in D with the brake applied.

2. Car bucks quite aggressively when cold (left overnight) between 1400 and 2500ish rpm up to around 80 degrees C

3. If I let the car change automatically when cold it doesn't seem to hold a high rpm before changing gears and changes down to 3rd at a low speed which puts the rpm down to around 1200 and a nasty groaning noise is made from the exhaust/gearbox area. Below and between the front seats.

4. There seems to be no fast idle on cold start it starts at around 900rpm then after a few seconds drops to about 670ish rpm (iirc) although it's been around 2-3c the last few mornings.

5. If I've just been out in the car and leave it for say 2 hours then drive it, the car runs as it should

6. MPG seems a little low at around 37mpg on a 20 mile round trip half of which is motorway travel.

7. Sometimes the engine note changes, usually after say 15-20 miles of driving, the engine becomes very smooth and much quieter than it normally sounds and there seems to be more throttle response.

So far I've replaced the 2 idler pulleys, alternator pulley, belt, new MAF, battery, belt tensioner, one injector, all injectors tested fine and have been cleaned and the injector seats have been cleaned and re cut and stretch bolts and copper washers were replaced and the injectors were coded.

STAR diagnostic showed no faults other than alternator over charging due to a seizing clutch pulley. My mechanic couldn't find any other obvious mechanical faults. Full service was done 5k miles ago (car was doing this before the service). Gearbox has been serviced. I removed and cleaned the EGR valve system but not the EGR cooler (seems hard to get at). New seals on high pressure fuel pump and new fuel lines and fuel return lines. New thermostat and coolant temp sensor.

I did notice the waterpump pulley seems a bit stiff and moves slightly if I wiggle it in and out.

its beginning to baffle me as I've quickly run out of ideas and can't seem to find anything online that relates to my cars symptoms.

Any ideas are welcome. I appreciate you taking the time to read this and I apologise for it not being a short introduction

James.

 

[Pitts Pilot]

Re-flash the ECU? Or update the ECU firmware?

Might be a fueling issue?
Needs it to be a tad richer when cold?

Main Steeler for that.....

Cheers,
Robert



.

 

[buzzc1989]

I forgot to add that there is some oil leaking from the crank case vent seperator area and there seems to be quite a lot of oil being sucked through that tube that connects the vent to the intake (before the turbo) which obviously is being sent through the intake into the engine. could a faulty oil vapour seperator have anything to do with this problem? If the oil pressure is suffering for example? I believe there's some kind of valve that opens and closes depending on the crank case pressure, if it's stuck closed or open could it cause the issue?

I look forward to hearing ideas.

James.

 

[buzzc1989]

Re-flash the ECU? Or update the ECU firmware?

Might be a fueling issue?
Needs it to be a tad richer when cold?

Main Steeler for that.....

Cheers,
Robert



.

Thanks for the reply Robert. I was thinking that the problem would be apparent more of the time and not just when the engine is cold. I'm not dismissing the idea and think maybe a deeper diagnostic needs to be performed.

Do you have any idea how much a stealer may charge to reflash/update the ECU?

James.

 

[Pitts Pilot]

I was thinking that the problem would be apparent more of the time and not just when the engine is cold.

Do you have any idea how much a stealer may charge to re-flash/update the ECU?
James.

My SL is juddery when cold. I almost 'kangaroo' up the street until the oil temp has got past 80c!

Had the same problem on a BMW M3 I had years ago. On that occasion I had it re-mapped and asked them to increase the fueling a bit when stone cold. Fixed the problem immediately!

As for ECU reflashing at a main stealer, £250? They should be able to quote you before hand…

Cheers,
Robert


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[Pitts Pilot]

3. If I let the car change automatically when cold it doesn't seem to hold a high rpm before changing gears and changes down to 3rd at a low speed which puts the rpm down to around 1200 and a nasty groaning noise is made from the exhaust/gearbox area. Below and between the front seats.

I don't like the sound of that (no pun...).

Don't know where in the UK you are, but I'd have someone 'new' have a listen to the gearbox. (Fresh pair of ears, etc.)

Sometimes a main stealer can actually be useful because they have access to a vast record of online trouble shooting problems.


For example: I had a whirring sound from the gearbox/rear dif. So I had MB Basingstoke have a listen and it turned out to be a 'damper' on the ABC suspension!

Not saying it’s your suspension, just that sometimes it can be something completely off-beat and seemingly unrelated.


Incidentally, gearboxes have ECUs too

Robert

PS. When was the last time you had the gearbox oil changed?


.

 

[SteveFromAvantgarde]

When it bucks does it then go into limp mode but then reset when the ignition is switched off and on?

 

[buzzc1989]

I don't like the sound of that (no pun...).

Don't know where in the UK you are, but I'd have someone 'new' have a listen to the gearbox. (Fresh pair of ears, etc.)

Sometimes a main stealer can actually be useful because they have access to a vast record of online trouble shooting problems.


For example: I had a whirring sound from the gearbox/rear dif. So I had MB Basingstoke have a listen and it turned out to be a 'damper' on the ABC suspension!

Not saying it’s your suspension, just that sometimes it can be something completely off-beat and seemingly unrelated.


Incidentally, gearboxes have ECUs too

Robert

PS. When was the last time you had the gearbox oil changed?


.

The gearbox oil and filter were service about 1500 miles ago.

The car doesn't go into limp mode and restarting the engine doesn't make a difference. It starts up fine it's a very strange situation. No warning lights, no fault codes.

I have taken the PCV off which has the oil filler part attached and if I hold all the screws in place (they are secured to the part so they don't fall in the engine I presume) I can't hear any rattling. I can blow freely through the valve which makes me believe the valve is stuck open? That explains my situation if you search for pcv valve stuck open. I wonder if there is actually a valve in the part I'm not sure how the c220 cdi engine pcv works? Can anyone shed some light please

Jim.

 

[camerafodder]

Re-flash the ECU? Or update the ECU firmware?

Might be a fueling issue?
Needs it to be a tad richer when cold?

Main Steeler for that.....

Cheers,
Robert



.

Just for reference, diesel engines don't run rich when cold. When stationary and cold is your idle stable?
I'm wondering if your problem is transmission related, perhaps torque converter or lock-up mechanism?

 

[buzzc1989]

Just for reference, diesel engines don't run rich when cold. When stationary and cold is your idle stable?
I'm wondering if your problem is transmission related, perhaps torque converter or lock-up mechanism?

I think the idle is stable when it's cold (when I've just started the car) if I give it a blip of the throttle then the rev counter bounces a little (barely but it moves)

I'm not familiar with how auto boxes work, is there a way I could test either one? It does seem as if the gear box slips actually. I was hoping for something simple hopefully it's not either of those... I've spent a lot already and possibly been looking at the wrong parts lol.

Jim.

 

[pembssurf]

Just for reference, diesel engines don't run rich when cold. When stationary and cold is your idle stable? I'm wondering if your problem is transmission related, perhaps torque converter or lock-up mechanism?

Normally on a cold Diesel engine the timing is advanced. Perhaps there is an automatic advanced on these engines which is sticky?

 

[buzzc1989]

Normally on a cold Diesel engine the timing is advanced. Perhaps there is an automatic advanced on these engines which is sticky?

I was wondering whether it could be something to do with the EGR system but at the same time was thinking it would show a fault code. It's frustrating that the problem goes away or maybe it doesn't but isn't noticable so much when the engine is warm.

I looked into how auto boxes work and am now thinking that worn seals in the hydraulic system could be letting pressure passed and not engaging the clutches fully. Then as the gearbox warms up, the seals are sealing the pressure better and the clutches are engaged properly. I've put some stop leak in and will see how it is after a few days. I figured it won't do any harm (let's hope not..)

Jim.

 

[camerafodder]

Normally on a cold Diesel engine the timing is advanced. Perhaps there is an automatic advanced on these engines which is sticky?

Good suggestion, on this engine it will be controlled electronically by the ECU I expect. I'm still favouring gearbox issues at the moment though.

 

[buzzc1989]

Good suggestion, on this engine it will be controlled electronically by the ECU I expect. I'm still favouring gearbox issues at the moment though.

Just an update. So far the stop leak hasn't made any difference. It may be too early to tell if it's made it slightly better or not changed anything.

There is a motor controlled flap after the intercooler pipe (the EGR valve flow pipe diverts in behind this moving flap. When I switch off the engine the flap vibrates. I think it's the shut off flap which doesn't seem to "shut" it just barely moves and makes a ticking noise as the engine is shut off. The engine does shut off pretty roughly but not too bad that it causes me concern

 

[hollyhocks]

Hi did you change the alternator pulley, we had that and it was very rough and the belt vibrated so badly it damaged a fuel line. New pully and ok after . good luck

 

[buzzc1989]

Hi did you change the alternator pulley, we had that and it was very rough and the belt vibrated so badly it damaged a fuel line. New pully and ok after . good luck

Hey, yes the alternator pulley was replaced a couple of weeks ago. The waterpump pulley feels a little gritty and very slightly loose but not as if it's failing.

I only had the car for a week before changing the thermostat, I can't remember the car bucking when cold before this. I wonder if a bad thermostat would cause this? I changed the temp sensor recently as the new stat didn't have one included and read that a bad temp sensor could cause problems when the engine is cold which made no difference. I tried to bleed any air out of the system but not 100% sure there isn't an air lock. The stat only seems to open when at full temperature rather than a gradual flow of water as the car warms up to temp (I tested this by feeling the upper radiator hose coming out of the thermostat)

 

[E270 Owner]

MB Star session is needed and checked on smooth idle/running mode.

 

[buzzc1989]

MB Star session is needed and checked on smooth idle/running mode.

I'm beginning to think it does need more in depth testing. The fluctuating idle is minimal and Intermittent. Sometimes the idle is dead steady. No sensors are throwing faults. Tomorrow I'm off work so I will try to get a better look at all the air intake pipes. The only ones I haven't been able to check properly are the intercooler inlet and outlet where they connect. There does seem to be a gathering of oil where the outlet is but I assumed that's oil dripping when the system isn't under pressure like overnight.

Jim.

 

[buzzc1989]

I have another question. I accidently forced the car into limp mode and only realised when I was driving along and had no power. However the engine was in the temp range it normally jerks, the engine seemed much smoother! I'm wondering if there's gunk built up in the turbo and the engine is over/under calculating pressure. I don't want to take off the turbo so may get the garage to have a look and see if it's a possibility.

 

[E270 Owner]

I have another question. I accidently forced the car into limp mode and only realised when I was driving along and had no power. However the engine was in the temp range it normally jerks, the engine seemed much smoother! I'm wondering if there's gunk built up in the turbo and the engine is over/under calculating pressure. I don't want to take off the turbo so may get the garage to have a look and see if it's a possibility.

Just get it on MB Star and have it diagnosed properly and save money