E60 M5 'driving style detune' reset?

[simonpa]

Been reading Eddie's fantastic buying guide sticky again and had a question regarding the 'detune' the car performs to suit the owner's driving style.

Can this be reset, by disconnecting the battery, for example?

I have an occasional hesitation, that could be down to this, or possible fuel/pump pressure, when pushing on.

TIA - Simon

[jcolley]

simonpa said:

Been reading Eddie's fantastic buying guide sticky again and had a question regarding the 'detune' the car performs to suit the owner's driving style.

Can this be reset, by disconnecting the battery, for example?

I have an occasional hesitation, that could be down to this, or possible fuel/pump pressure, when pushing on.

TIA - Simon

The only adjustments the mss65 DME "learns" are the adaptation values which are stored to correct for the minor variances in fuel trims (AFR), throttle actuator offsets, idle actuator offsets, MAF offsets, cylinder specific injector and airflow variances, O2 sensor offsets, etc. There are no parameters stored in the DME which take into account the driver's habits. The adaptation values can be reset using INPA, DIS, or ISTA/D however. It is possible that resetting them may improve performance, but this is more of an indication of deviation of the engine as a whole across the entire powerband from original spec.

Say for example you have a small air leak on the intake, allowing the engine to gulp in air which bypasses the MAF. The DME knows there is extra air because the pre-cat O2 sensor detects the exhaust a little lean. It adjusts (increases) the fuel injector pulsewidth to correct the AFR. Over time, the DME realizes it's *always* having to add a little extra fuel to maintain AFR and stores that in the "adaptation" values.

Now, the DME isn't advanced enough to have an adaptation curve stored for that which takes into account % power. It only has a single value which it calculates based on what it sees most often as necessart.

If you have a small air leak, a little bit of extra air will sneak in at low power, and a lot of extra air will sneak in at high power. Since the DME knows the car is driven around a lot a low power conditions, the adaptation value stored is done so for the most common error, a low power condition.

So, at higher power demand, the DME finds the mix lean again since there's more air leaking in which isn't accounted for by the MAF adaptation value, so it tries to correct the mix *after the fact* instead of properly predicting it before hand.

Recently in the US, an individual who had purchased an S85 6.0L stroker was seeing great gas mileage in town, but the car seemed much weaker than it had been initially. After a trip to the dyno, it confirmed a 100HP or so loss. The DME adaptations were cleared and another dyno pull made. The engine almost immediately gained nearly 100HP back for several successive runs. Driving back home nearly 1000 miles, the engine then re-learned the everyday adaptations and overall power output when called for was reduced. In this case however, this is an indication of a less than optimal tune which only full power tuning was conducted in-car and not on an engine dyno at varying load levels.

If you are on the stock tune, it might be worth investigating spark plugs, clean the MAFs, change air filters, inspect the intake plenum couplings to the throttle bodies (S85 plenums are notorious for being improperly installed).

Also, reading out the DME for any error codes is a good place to start.

[simonpa]

Many thanks for that comprehensive answer, JC - I have a lot to learn!

I've only had the car a couple of weeks and will go through the service history again to check when plugs, etc. were last done.
The throttle actuator was changed some time back, so a check the TB connections are secure is sound.

Cleaning and refixing MAFs, checking the plugs and changing filters are a good idea. I'll do that too.

Is resetting the DME adaptations afterwards something that can be done simply, or will it need to be done by a specialist?

Thanks again,

Simon

[Shaoxter]

Just to make sure - are you talking about the gearbox or the car in general? If it's the gearbox being sluggish in D mode then the solution is easy - drive in S5 mode all the time!

[Schermerhorn]

Driving in automatic mode will probably be contributing to a certain driving style being recognised and set with the SMG etc parameters. Not only that but auto mode is sh*te too. I only ever drove my M6 in auto mode twice......both by accident!

I would programme the car to S5 P500Sport model and drive it in manual mode all the time. Give it a slight lift on gear upchange and it'll save the clutch too. Give it some beans and it'll re-learn to a more 'sportier' set up for you.

[AW10]

jcolley said:

inspect the intake plenum couplings to the throttle bodies (S85 plenums are notorious for being improperly installed).

Thanks for another useful post. Can you elaborate on what the common mistakes are on plenum installation?

[simonpa]

Shaoxter said:

Just to make sure - are you talking about the gearbox or the car in general? If it's the gearbox being sluggish in D mode then the solution is easy - drive in S5 mode all the time!

I'm talking about the engine output specifically.

I've noticed how the gearbox changes in D can change significantly, depending on how you drive - use kickdown a bit and it will hold changes longer for a while, even if in D1 or 2.