stuartinzg said:
Zap results:
http://datazap.me/u/stuartinzg/serviced?log=0&data=4-18-21-25
Seems to be some timing corrections but I don't really understand it - can anyone help me out?
That log is fine for stock.
The stock map is far from perfect and if that log were to come from a tuned car I would advise you ask them to re-do it!
The main points I check are:
Cyl1-6 Timing Cor* - These are the timing corrections that are due to knock. This log doesn't have any but minor corrections are fairly normal even on a stock car.
Boost mean PSI vs Boost target PSI - I compare these to make sure the boost is smooth and at least shadowing the requested boost. Oscillating boost mean PSI would mean the PID is setup poorly and needs tweaking.
Throttle Position - This should read 81 while your foot is on the floor. If your accelerator pedal position reads 99.6% and the throttle is reading less than 81 that means the DME is intervening and closing the throttle for some reason. The usual causes are traction control and the boost mean PSI going above the boost target PSI.
In your log the car is overboosting above 6000RPM so the throttle closes slightly to reduce the boost.
Timing cyl.1 crk* - This is the actual ignition advance being targeted. All cylinders target the same ignition adv unless knock is detected. In that case the individual cylinder will temporarily have a correction factor applied to prevent super knock.
In your log the timing is great until you shift. During the shift the boost spikes and the DME retards timing (this retardation is not logged as a correction because it's not knock related). You see that purple line jumping about after the shift, that's the DME trying to protect the transmission from excessive torque
I think. It's normal for the timing to go flat for a millisecond during shift but it should jump right back up after, and not dip like in that log.
The boost spike during shift is something I'm trying very hard to tune out on my own map, it seems to happen on all DCT transmissions and is probably due to the speed of the shift and the timing retardation the DME uses during shift to lower engine torque and aid clutch engagement.
stft 1% and stft 2% - These are the short term fuel trims applied to banks 1 and 2 respectively to keep the AFR on target. Basically anything above 15% or below -15% is bad and you're engine is getting close to being unable to achieve the correct targeted AFR. This is usually down to bad Lamba sensors, bad injectors or fuel pumps not supplying enough pressure to the injectors.
There is also long term fuel trims that can be logged, you should try ticking those in the logging options. You can read up about long and short term fuel trims on any forum as it's a common air/fuel management system applied to all engine ECUs.
Fuel low pressure sensor - The N54 usually has a low pressure fuel sensor. If this reads below 50 you have a bad low pressure fuel sensor. The Z4 35i/s is the only car with an N54 not to have this sensor. This is probably due to the fact we have a much better fuel pump than other N54 cars with larger diameter fuel lines so it was deemed unnecessary.
Rail Pressure PSI - If this falls below 1500 you have a bad high pressure fuel pump and should get it sorted. The car will not go into limp mode in the event on a lean running condition so you can actually cause serious damage pushing the car hard on a bad HPFP.
Lamba Bank 1/2 AFR - This is the air fuel ratio reading in each respective bank. Stock cars run rich, tuned cars will run a little leaner for more power and fuel econonmy. If you look at the readings of both banks during overrun while the fuel is cutoff to the engine you should see both readings max out at 234.95. If one is reading anything less you have a leaking injector in that bank.
These are the key channels I tend to look at when evaluating a log. If you ever decide to custom tune your car you will get to know more channels but if you are just evaluating the health of a car and not trying to tweak a map the above points will serve you well.
With the DCT the
torque limit active channel is also quite useful. On tuned cars you sometimes get values in that channel during shifts which indicate transmission slip and over torque. JB4 users will tend to see these more than others as their crappy little piggyback toasts their clutchpacks
With the MHD maps you will be safe. Wedge knows how to manage the DCT shifts in his tunes.
When you decide to apply a tune to your car feel free to post the logs here and I'll take a look for you.
