V6 CDI/7G hesitation

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developer

MB Enthusiast
SUPPORTER
Joined
Dec 28, 2007
Messages
8,228
Car
Volvo V90 D5 AWD
Brabus chip
Latest gearbox software
No fault codes
ATF changed at 38K

However, I still have an annoying delay which shows itself from standstill and again at kickdown.

Turbo lag?
Gearbox characterstic?
Normal?

More importantly - can it be eliminated?

ps - I'm not driving in C ;)
 
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Sounds like a bit of a strange one John.. As far as I was aware the hesitation issue only really presented itself on the BlueEfficiency models because of how the gearbox is set up to work in order to lower emissions?

I had it on mine initially but after having the latest auto 'box software loaded some time last year it went away all together.

How do you drive? The gearboxes learn your driving characteristics which if you just plod about and don't give the loud pedal enough attention can make you believe there's an issue with the way it shifts up and down but after a few "blasts" though the gearbox that goes away.

(On a slightly different note, having my Brabus installation certificate posted out tomorrow from the dealer).
 
i had that on my 2007 57 plate e320 sport with 7G, seemed like a characteristic to me, was a bit worrying sometimes when i put my foot down and nothing happened. suspect turbo lag however did seem better have after the gearbox oil changed at 37K.

Have you had the oil changed in the gearbox?
 
Sounds like a bit of a strange one John.. As far as I was aware the hesitation issue only really presented itself on the BlueEfficiency models because of how the gearbox is set up to work in order to lower emissions?

I had it on mine initially but after having the latest auto 'box software loaded some time last year it went away all together.

How do you drive? The gearboxes learn your driving characteristics which if you just plod about and don't give the loud pedal enough attention can make you believe there's an issue with the way it shifts up and down but after a few "blasts" though the gearbox that goes away.

(On a slightly different note, having my Brabus installation certificate posted out tomorrow from the dealer).

Hello Nab,

While they d*cked about with the chip I had a 220CDI. Fabulous shove from no revs, all the time, every time, though it's a twin turbo.
Also if I'm on the motorway say 70 (;)) and I go for kickdown there's a delay while the right gear is selected and then away we go. It's very annoying.

ps, good news about the cert :thumb:.
 
i had that on my 2007 57 plate e320 sport with 7G, seemed like a characteristic to me, was a bit worrying sometimes when i put my foot down and nothing happened. suspect turbo lag however did seem better have after the gearbox oil changed at 37K.

Have you had the oil changed in the gearbox?

Sorry, I forgot to add, the ATF was changed at 38K.
 
I have this delay as well John.

It's only a split second, but it's there.

This same delay made an Audi driver think he had the jump on me from the lights today. You've got to give them a headstart I suppose, or it wouldn't be fair now would it? ;)
 
I have this delay as well John.

It's only a split second, but it's there.

This same delay made an Audi driver think he had the jump on me from the lights today. You've got to give them a headstart I suppose, or it wouldn't be fair now would it? ;)

Hello Lee,

I wonder if the 7G+ box is any better - I hope so.

I found that a 170bhp 220CDI was much much better away from standstill - a proper diesel shove with 100bhp less - it's just not cricket :confused:.
 
Same story on wife's 2010 C350 CDI Kleemann chipped. Friggin' delay annoys me to no end.
 
Its the 5 speed box John, its just well, better.

Sorry, all the cars have a delay, there will be nothing fundamentally wrong with your car, just like the rest of the V6 cars, it has a ****ing **** gearbox.

Try if you have issues with it, using the "hold" feature when stopped, or holding the car on your left foot, and use your right foot to move it. Try using the S mode as it will stop and use 1st gear to move, but your car does not have the decoulping device which gives the later 212s which have a slight delay before taking off.

Alternatively, adopt a driving style of "slow to go" and try not to stop and to keep the car rolling, however slowly....
 
*** - it's not the box. The box is way better than the 5 speed in almost every way other than the reach of 1st and 2nd which are a little too low (bragging rights are scuppered as it needs 3rd gear for 100km/h)

The engine is laggy though, lift the cover and look at the size of the turbo nestled by the firewall in the vee, it's not small for a car turbo and it does take a bit to spool, having to flow enough air for up to 240bhp and raise the inlet pressure by 21psi in my car.

I tend to find myself driving in "M" for spirited driving, C most of the time and S very rarely.

Once the turbo has spooled up though it's a big grin every time.

The coupe I drove (see my review) was a 220 twin turbo with the 7speed and was far more responsive, but you miss the power the 320 has.
 
A Message from John (Developer215)

Hi All,
I got a text message today from john (Developer215), to say he is at his Sisters in Scotland and that her broadband has been disconnected.
So he says to tell you all he wont be able to post on the forum for a few days or so. He is hoping to be back on Thursday.
His normal service will resume as soon as possible.:D
He didn’t want any of you to think he was ignoring you..:(
Brought to you via the SSpeed messaging service.

P.S My E320 Cdi didnt hesitate at all on the motorway when overtaking..
I have had 2 cars with the 7 speed box and both were very good indeed.
My only issue with the 7 speed is / was the half ****d way that the ATF is changed.
 
Mine also has a slight pause when changing on normal roads but on the motorway its more or less instant.
 
I find mine has huge lag you can go 1,2 away you go
It drives me nuts
 
As *** says it's definitely the box the same size turbo coupled to a 5 speed box does not have the lag If you want a drivers car then the 7g box is the worst thing possible 5g is miles better, sharper, better response, no lag and far more reliable. If it's one of the early 7g boxes then you have to live with the lag not a lot you can do about it, software upgrades help but never cure it.

A tuning box or remap with a 7g box IMHO is not a good idea, keep it standard and you can eliminate the lag to near zero go for performance gains and the problem gets worse.
 
Can only mb dealers do software upgrades? Also where/how do you find out what version you are currently on?
Having these cars are worse than owning an iPhone!
 
As *** says it's definitely the box the same size turbo coupled to a 5 speed box does not have the lag If you want a drivers car then the 7g box is the worst thing possible 5g is miles better, sharper, better response, no lag and far more reliable. If it's one of the early 7g boxes then you have to live with the lag not a lot you can do about it, software upgrades help but never cure it.

A tuning box or remap with a 7g box IMHO is not a good idea, keep it standard and you can eliminate the lag to near zero go for performance gains and the problem gets worse.

I've had 4 Mercedes with the 5 speed, 3 of which were the IL6 engine and this is my first V6 7 speed.

Besides the very slight delay what John is referring to, the 7 speed, in my opinion and experience makes the 5speed feel old and cumbersome. The gear changes are smoother, there is less jerking when dropping a gear etc etc.

I find myself using the tiptronic more on this car than I ever did with the other 4 that had the 5 speed, meaning that it's a more responsive and involving gearbox.
 
I've had 4 Mercedes with the 5 speed, 3 of which were the IL6 engine and this is my first V6 7 speed.

Besides the very slight delay what John is referring to, the 7 speed, in my opinion and experience makes the 5speed feel old and cumbersome. The gear changes are smoother, there is less jerking when dropping a gear etc etc.

I find myself using the tiptronic more on this car than I ever did with the other 4 that had the 5 speed, meaning that it's a more responsive and involving gearbox.

I would agree with you but the 7g is a lot more fragile than the 5g, smoother and refined yes, but I'd be prepared to sacrifice some of that refinement for durability. We've seen 7g boxes fail very early in their lives and also had far more 7g boxes in than we ever have 5g, Can't remember the last time we saw a 5g failure but 7g although not common do have a lot of problems. But from a driving perspective yes the 7g is more involving with tiptronic. I wonder what the new 9g box is going to be like :dk: or is that a gear too far :dk:
 
I was advised to go for the V6/7G combo when i bought my car, but imho i'm not convinced i made the right choice. The tip i don't use simply because my brain cannot comprehend moving the stick left/right so i end up just leaving it in drive:dk:.

Sorry to sound like a stuck record, but can someone please advise where i would find out what software my box is on and if it is just a MB dealership job to get it updated?

I've had the ATF changed but to me it is still jerky in the first 2 gears on pull off and sometimes just holds onto gears without change up for no apparent reason.:confused:
 
While taking part in a drag racing series in the race car I had some time to to give the Merc (CLK320 CDI) a few runs just to see what it could do.
I have been racing front/rear and 4WD cars for years and I couldn't get the Merc to play.
I think the delay is the electronics limiting the power to avoid breaking things, basicity taking over and doing what it thinks is best rather than allowing the driver to modulate the right foot.
Was tempted to totally disable the ESP in the hidden menu but it's my daily driver, the delay is awful when pulling out onto busy roundabouts, go for the quick pull away and you end up pulling in front of the car you thought you had time to avoid.
 
Thanks everyone for your replies.

I was concerned that I'd asked a question and then disappeared, but I'm back now :thumb:.

I'm taking the car back to the dealer under warranty for the diag tech to have a drive.
 

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