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STFT B1 etc...
- Thread starter andysat
- Start date
Nelly Welly
Active member
Andy
Those variations are good the s should be relatively stable the differential I the l again supports and air leak.
Those variations are good the s should be relatively stable the differential I the l again supports and air leak.
Thanks for your continued help, should that LTFT B2 be in the minus tho?Nelly Welly said:Andy
Those variations are good the s should be relatively stable the differential I the l again supports and air leak.
Nelly Welly
Active member
Above and below but should be less than one unit minus is ok.
Phew!-cheers!Nelly Welly said:Above and below but should be less than one unit minus is ok.
Nelly Welly
Active member
The oxygen sensors are what drive the fuel trim readings. Changes in o2 sensor voltages cause a direct change in fueling rates. The short term fuel trim (STFT) refers to immediate changes in fuel occurring several times per second. The long term fuel trims (LTFT) are driven by the short term fuel trims. LTFT refers to changes in STFT but averaged over a longer period of time. A negative fuel trim percentage indicates a taking away of fuel while a positive percentage indicates an adding of fuel.
Adding fuel can be a result of extra air being present that has not been metered, reducing fuel can be a result of engine overrun (engine braking on longer journeys). Both are acceptable but continual variations eg positive then negative or maybe 2.5 on one session and 4.8 on another tend to indicate issues with air and vacuum within the combustion cycles.
Hope all this techy helps find the issue, but I am drawn back to incompatible O2 sensors or an air leak on the inlet side.
Adding fuel can be a result of extra air being present that has not been metered, reducing fuel can be a result of engine overrun (engine braking on longer journeys). Both are acceptable but continual variations eg positive then negative or maybe 2.5 on one session and 4.8 on another tend to indicate issues with air and vacuum within the combustion cycles.
Hope all this techy helps find the issue, but I am drawn back to incompatible O2 sensors or an air leak on the inlet side.