Initial Break-in?
10-24-2017, 04:36 PM
#26
Member
Not specifically, but if the light is on, there's a code. Have it scanned and see what it is.
On tuned cars, I've seen plenty of instances of codes setting related to parameters changed by the tune, unfortunately the first step to making sure the parts are working properly is to put a factory calibration back in it and see if it returns. On my tuned CL, there's very little in the way of airflow diag. On these new 177/178 engines, they check everything, and there's stuff the tuners can't see or don't know needs to be addressed. The increased airflow from the tune can cause strange issues.
On tuned cars, I've seen plenty of instances of codes setting related to parameters changed by the tune, unfortunately the first step to making sure the parts are working properly is to put a factory calibration back in it and see if it returns. On my tuned CL, there's very little in the way of airflow diag. On these new 177/178 engines, they check everything, and there's stuff the tuners can't see or don't know needs to be addressed. The increased airflow from the tune can cause strange issues.
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ecmexchange (11-02-2017)
10-24-2017, 07:14 PM
#27
MBWorld Fanatic!
Thanks again for the technical insight. Question, are you referring to the can buses that store engine information outside of ECU, that cannot be seen by tuners. ? If so can you elaborate?
My understanding is that guys who get second ECUs on tuned cars, don’t understand that this information is stored in those buses and therefore the second ECU is useless.
My understanding is that guys who get second ECUs on tuned cars, don’t understand that this information is stored in those buses and therefore the second ECU is useless.
These cars use Flex-ray, which is a high-speed, time regulated CAN for the powertrain, it's much faster than the old systems. The different bus system require a dedicated powertrain control module that is the master of the Flex-ray CAN, Not actually relevant here, just sharing lol.
The newer M/Es have hundreds of tables related to airflow/fuel. Most tuners will not edit all of them, they hit the main couple tables that raise boost and fueling, control timing, etc. There may be multiple tables that they haven't decoded in the software yet, and aren't visible. When limits get exceeded, codes set, and the car goes into limp mode to protect itself. It's much more time consuming to build OEM quality tunes in these newer computers, and is somewhat of a trial and error process since we are technically reverse-engineering the factory software to figure out what goes where and what each table means.
If you didn't have the problem with the stock tune, or you put the stock tune back and it goes away, speak with your tuner. He may be able to figure out what adjustments need to be made to prevent the faults from setting again. Could be very simple.
11-02-2017, 08:40 PM
#29
