Reset ECU's for high altitude - Fact or myth?

seems fairly reasonable to me. The density of air can have major impacts on an engine's performance, etc.

Ray

 

Live in Reno and I just recently had my ECU'S reflashed by the dealer (FoSF). At cold start my CS would run very rough. I would have to turn the engine off and repeat a few times to smooth the idle out. This problem only occured at high altitude in the winter time. The reflashing fixed the problem.

I'm not sure how the battery disconnect procedure would have worked. Never tyried it!

 

I was told by my dealer that Enzo and CS needs to idle for 15-20 mins in order to calibrate baseline parameters if the battery is ever disconnected.

My friend had purchased a set of Hyperflow for his CS and after installation, it was clearly running very rich and the performance gain was minimal. I had him disconnect the battery over night and reconnected it, start the car and idled for 20 mins. After the procedure, the car ran much better. After a few more drives the ECU continued to learn and the car is clearly faster and more powerful than his 2nd CS.

These procedure are very common and have been true on BMW and Subaru...and I am sure many other automakers.

 

It makes sense, the car 're-learns' the new parameters such as ignition advance, fuel octane rating, etc. This approach simply speeds up the process, if it had to re-learn from such a drastic change such as fuel-air ratio being so different (different atmosphere conditions, sea level, etc. will effect the amount of oxygen in air) it *WILL* eventually 're-learn', however it will just take longer to do so if it didnt 'forget' its learned parameters......

 

Generally after most performance modifications or drastic altitude changes you want to let the car remap.

 

I think Rifledriver was referring to the idea that if you force a reset on your ECU your effectively 'hiding' or 'losing' if you like all of those fault codes that may have been logged. These are actually vital pieces of information for service centers to check the health of your car and remedy these problem.

Obviously if there are no faults to report (you can buy a reasonably cheap OBD code reader these days anyway...) then there is no harm in a reset, especially if your doing it for a specific reason and not just to clear 'i.e. hide' a fault code.

T

 

I think it is all BS. I live at 8300 feet. Engine management systems have all the sensors they need to adjust mixture and timing on the run. I have taken cars from 5K to 14K and back without them missing a beat although power is, of course, down just from lack of air. It is true with modern Ferraris that if you disconnect the battery, it takes a while for everything to reboot when refired (including the F1 trans mapping). It has nothing to do with altitude.

Dave