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LTFT STFT and ECU adaptation thread + Open Loop Effects (if any)

2K views 1 reply 2 participants last post by  Subby_ 
#1 ·
Just a thread starter to capture some thoughts on Long Term Fuel Trends, Short term and how the ECU makes sense of the issues.
Particularly interested for changing to larger injectors.
The LTFT should go more negative, however how will this effect injector pulse width in WOT in open loop mode when compared to a higher LTFT using stock injectors?
 
#2 ·
with most cars LTFT only trims injectors in closed loop (i.e. idle and cruising etc). with the mercs the LTFT does impact open loop.. im not 100% sure if thats the way on the bosch 2.8 ME ecu but it is the case on the slk230 bosch 2.1 ME ecu.

after tuning and larger fuel reg mine sits at -32 LTFT. yes this throws a code but i need that much fuel. monitoring the car with my wide band it runs fine.

idle cold start - around 12.2:1
idle warm - around 14.6:1
partial load - around 12.2:1
crusing - around 14.6:1
WOT - drops to 11.8:1 and creeps to 12.4:1 thereabouts
 
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