Tuning

Getting Started

Things you need

1. KWP2000+ OBD cable
2. KWP2000+ flashing software
3. TunerPro
4. XDF file for the revision of ECU you are using. If you wish to use a different version software than your car came with, read this carefully.
   • XDF for M-box.
5. ECUFix (optional, some KWP2000 flashing software will do checksumming for you)

Fueling

Always start with this first. If you get fueling wrong, you will likely break something. Get this right, and do not try pushing the envelope in any tables until you are confident your fueling is where you want it. Always use a wideband sensor. DO NOT skimp on this. The stock narrow bands do not provide you with accurate enough readings.

• MLHFM - compensate for MAF housing diameter. Some argue that using a different MAF housing (to extend the functional metered flow range) requires you to fix this so that measured load is "correct". The upside is that all of Motronic's tables that are based on load are probably still good. The downside is that you may hit the hard limit of load, and you'll go lean at high loads because the ECU can't tell how much air the motor is ingesting. That's obviously very bad. If that's the case, you'll definitely want to scale back the MAF readings some. Even if you don't ride the hard limit, you'll also run off the end of the load axis in the timing tables. Some say this isn't so much of an issue.

• KRKTE - primary fueling. Start with this to get your WOT AFR to roughly match your requested AFR. If you are using stock injectors and fuel pump, you should not have to touch this.

There are two ways to adjust requested AFR:

• KFLDBTS - requested lambda for component protection when calculated EGT is above TABGBTS (may require a lower TABGBTS if your MAF is not 100% compensated for in MLHFM)
• LAMFA - requested lambda when calculated EGT is below TABGBTS

Once you get your WOT AFR right, you may notice that your LTFTs are way out of whack. If they get too far out, you'll throw a code and possibly go into limp mode.

• KFKHFM - Correction map for MAF. Log STFTs to determine where the MAF readings need tweaking. If you are using the stock MAF and intake system, you should not have to touch this.

Now that you have your fueling set up, you'll probably notice that your MPG readings in your cluster are totally wrong. Fill up a with a tank of gas, and reset your trip odometer and average MPG. When you are done with the tank, fill up your tank, see how much gas you used and how far you went, and check it against the new average MPG. Get a calculator out, and correct it here:

• KVB - fuel consumption (MPG in cluster)

Boost

ME7.1 doesn't really have a "boost" table. It does everything based on requested load. Requested boost is roughly 10*(spec load)+300mbar.

First, make sure the 100% pedal position requests enough load:

• KFMIRL - specified load

At WOT, specified load will ride these limits:

• LDRXN - maximum specified load
• FLKDHBN - maximum requested pressure ratio

ME7.1 will adjust the limit depending on IATs. As IAT's go up, ME7.1 brings the max boost up a bit so that the driver can't tell that the car is slow in hot weather. However, at some point, if IAT's go high enough, you may want to pull max specified load a bit to prevent knock:

• KFTARX - IAT correction for maximum specified load

Cam changeover affect on requested boost

Motronic likes to change requested boost depending on cam position. While it may seem like a good idea in theory, in practice, abrupt changes in requested boost near the MAP limit can make the boost PID unhappy. When logging, you may see an odd notch in requested boost between 3000 and 4000 RPM. These maps are what is causing that notch

• KFPBRK - Correction factor for combustion chamber pressure
• KFPBRKNWS - Correction factor for combustion chamber pressure when NWS active
• KFPRG - Internal exhaust partial pressure dependent on cam adjustment when sumode=0
• KFURL - Conversion constant for ps->rl dependent on cam adjustment when sumode=0

Timing

When running elevated boost on pump gas, you will have to significantly cut requested timing to prevent timing retard. Keep your worst case correction factors in the single digits, and always carefully monitor your knock voltages when tuning your timing.

• KFZW/KFZW2 - primary timing maps. ME7.1 has a two point variable cam timing system; there is a table for each cam timing state.

If you did not fully "correct" your MAF using KFKHFM, make sure you do a lot of logging to see where the various load points are and how much timing ME7.1 is pulling due to knock activity. Most likely, you will have to adjust the *entire* map. If you did correct your MAF, you can probably leave most of the timing table alone, except at very high load.

Other niceties

Speed limiter

• VAVMX/VMAX - Speed limiter

Rev limiter

• NMAX - RPM limit
• NLLM - idle RPM

Left foot braking

Set either of these to maximum to prevent throttle cut when left foot braking:

• NWPMBBR - Minimum RPM for acc pedal value lockout on brake operation
• VWPMBBR - Minimum speed for acc pedal value lockout on brake operation

Knock control

Adjust these maps with care. Abusing any of them can cause severe detonation and probable motor damage

• KRFKLN - Ignition retard per knock event.
• KRALH - Load hysteresis. This adjusts how quickly timing will be restored as load changes.
• KRANH - Engine speed hysteresis. This adjusts how quickly timing will be restored as RPM changes.

Requested load cut on knock detection

• KFFLLDE - Factor for slow LDR intervention on rlmax via KR

Fuel enrichment on knock detection

• KFLAMKRL - Enrichment on ignition retard

Emissions

• CDKAT - Cat diagnosis in OBDII-Mode. Set to zero to disable rear cat DTC

References

Motronic abbreviations