Help! CL 600 2008 low on power, but no fault codes.

[Uncle Benz]

“Power drops while driving” suggests intercooler pump to me. I’m a little surprised that it’s not showing a fault code, but if the intake air temp is still within defined safe levels, albeit high, I suppose it won’t. You can run the pump via Star, but you’ll likely need a hand on it to see if it’s actually running. They are pretty quiet

 

[Tabraze Akram]

“Power drops while driving” suggests intercooler pump to me. I’m a little surprised that it’s not showing a fault code, but if the intake air temp is still within defined safe levels, albeit high, I suppose it won’t. You can run the pump via Star, but you’ll likely need a hand on it to see if it’s actually running. They are pretty quiet

Thanks,
It certainly looks like a likely culprit along with a boost leak.
Also I agree, probably within normal running parameters but enough to notice a power drop.
Gonna check for both of these today.
Will let you know how I get on.

 

[Tabraze Akram]

Update.
It’s not in my head!!!
Local garage has driven it and confirmed formed when you set off the power is all there, however when you put your foot down the power drops. Not into limp-mode or enough to set off any warning lights, but enough to feel.
So as suggested we are looking at
1) The IC coolant and pump.
2) Boost pressure and general vacuum check
3) MAF and O2 sensors.
Thanks for all the help and suggestions. Will let you know how I get on.

 

[alexanderfoti]

Update.
It’s not in my head!!!
Local garage has driven it and confirmed formed when you set off the power is all there, however when you put your foot down the power drops. Not into limp-mode or enough to set off any warning lights, but enough to feel.
So as suggested we are looking at
1) The IC coolant and pump.
2) Boost pressure and general vacuum check
3) MAF and O2 sensors.
Thanks for all the help and suggestions. Will let you know how I get on.

There are no MAFs on these engines (speed/density) so don't try and change those O2 sensors are unlikely and can be ruled out by checking adaption values for fuel trims.

 

[Tabraze Akram]

There are no MAFs on these engines (speed/density) so don't try and change those O2 sensors are unlikely and can be ruled out by checking adaption values for fuel trims.

Doh!!!!
The mechanic did say he could find any MAF sensors.
He’s looking at the fuel trim log and actual running data. Should give us a clue.

 

[mioba]

Are you using a merc indy btw

 

[Tabraze Akram]

Are you using a merc indy btw

No, local garage I’ve used for 10+ years. Well trusted and capable.
If we can’t figure it out will look for a specialist.

 

[Botus]

If you have a Bluetooth obd connector then you can use the Torque app.

air charge temp on torque app sounds pretty cool, never used it...but if it can find that (alongside boost) on a Merc V12 that's rather useful

 

[Tabraze Akram]

air charge temp on torque app sounds pretty cool, never used it...but if it can find that (alongside boost) on a Merc V12 that's rather useful

Thanks.
Inside to use the Torque app a while go. A friend has it and gonna pick it up later on today.
I’ll try it out.

 

[bembo449]

I use this app , usefull little thing to have thow i haven't used it on my MB as yet

 

[mioba]

I would be looking at using a indy with the correct diags, based on what you have said so far you could end up replacing bits till you replace the right one, which will hurt the wallet.

 

[Don_Muscles.]

Any update on this?

 

[Craiglxviii]

No, local garage I’ve used for 10+ years. Well trusted and capable.
If we can’t figure it out will look for a specialist.

Strongly suggest you do.

My CL500 has a similar issue of low power but smooth running. Fault code kept throwing out an auto adaptation issue. New MAF, all sorts were tried out...

It turns out that a family of mice had made their home in the valley between the cylinder heads, under the intake manifold, and had peed all over the the adaptation sensors and blowoff head plugs to the point they’d fully corroded. All were replaced and the car transformed.

 

[Tabraze Akram]

Sorry for the delay in the response.
It was the passenger side coil pack in the end. Two cylinders were not firing properly. Also the whole coil pack was not on full power. The driver-side coil pack looks like it was changed not long before I bought the car. Had it checked at Performance Prestige in Portsmouth. Work was done by prestige performance in Derby. Both I recommend highly especially Prestige performance in Derby the specialist there Ben really knows his stuff. The car he’s running and driving absolutely brilliantly now.