Cylinder cut off? Or something else?

[amwebby]

Today my 2000 CL500 suddently started running very rough as I pulled up to a red light. The idle was so lumpy I thought 1 or 2 cylinders must be misfiring. I took of and it seemed smooth enough at cruising speed but there did not seem to be as much power on tap as normal.

125 miles later I pulled into Watford Gap services, noted that the idle was still lumpy, turned the engine off and took a comfort stop. When I returned to the car and started it the lumpy idle was gone and, as I pulled away full power had returned.

Now, I know the CL500 had the option of cylinder cut off, but have no idea if mine has it or how to initiate it or even if that is what the problem was but it certainly seems like it as the power before 'reset' was just like driving a V6.

Anyone got any ideas what happened?

 

[SG CL500]

I'm normally shown to be wrong when i try to answer a technical question but i believe the (emissions reduction) cylinder cut-off was on US spec only cars and operate on one 'bank' of the v - i.e makes an inline '4'.

Unfortunately that makes it all sound a more serious reason for the apparent partial shut down

 

[i_york]

May not necessarily be anything serious... could be an HT lead going bad or possibly an air leak after the MAF causing unmetered air to enter the engine and upset the fuelling.

Cheers,
Ian.

 

[amwebby]

Should I worry?

Thanks, I'm not sure whether to worry or not now. Thinking about it, it couldn't be cylinder cut off as it was way too lumpy. The fact that it righted itself with a restart gives me hope. I'll see how it is today and get it in to check over the HT leads and MAF

 

[saorbust]

I'm normally shown to be wrong when i try to answer a technical question but i believe the (emissions reduction) cylinder cut-off was on US spec only cars and operate on one 'bank' of the v - i.e makes an inline '4'.

Unfortunately that makes it all sound a more serious reason for the apparent partial shut down

Nope - sorry. Its on any country spec car, but you could only order it for about 12 months. Bank on regarding the shut down execution - one bank is correct.

Its on both the V12 (non turbo version) and V8 engines - V12 has it as standard. V8 had it as an option.

 

[SG CL500]

Nope - sorry. Its on any country spec car...

told you

 

[amwebby]

So, how do you shut down one bank?

How do you shut down a bank or know if your car has the option to do so?

 

[SG CL500]

the shut down is automatic - activates under certain driving conditions

if its an option then it will be listed as such - get your VIN code a tap into one of the VIN look-up sites - this will give you a list of the factory options (i will try to search for the link but it has been posted on the forum before)

ta daaaa

 

[stats007]

It sounds like a MAF or Lambda / Oxygen sensor issue.

 

[se97mlm]

I'm normally shown to be wrong when i try to answer a technical question but i believe the (emissions reduction) cylinder cut-off was on US spec only cars and operate on one 'bank' of the v - i.e makes an inline '4'.

And it was a disaster apparently; never properly worked and made the software more than twice as big. Apparently the software logic diagrams and explanations from Bosch ran into more than 5000 pages.

Matt

 

[GazCaff]

I wouldn't have thought that idle speed was a condition were the engine would shut down cyliner(s) anyway. It would most likely do this when cruising tbh.

 

[Birdman]

[http://www.mbclub.ru/mb/vin/index.html?lng=eng ta daaaa

This is a Russian site. Now why would anyone want to input their VIN number into a site located in a country where all those stolen luxury cars wind up and are never ever recovered?

 

[Parrot of Doom]

What, like Liverpool?

 

[Birdman]

What, like Liverpool?

The scam's too complicated for a scouser.

 

[amwebby]

Well. I just got the CL500 back after the local dealer fixing the ABC fault mentioned eslewhere.

As I asked them too, they 'checked out' the performance/lumpy idle issue and reported back: "Investigated rough running, cleared fault codes from system, advise customer to try." Gee, thanks guys.