DME 5.2.2 Throttle By Cable
DME 7.2 E-Gas (Electronic Throttle)
DME 7.8 3-Chain and Turbo
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Oxygen Sensing or Fuel Trim Mean Value (Short Term Fuel Trim= STFT):
This is Lambda
Long term fuel trim is always working to keep this at “1”.
Less than one is rich and greater than one is lean.
Please note: When STFT strays from 1 and reaches its limits, LTFT adjusts to maintain 1.
When LTFT reaches its limits the CEL illuminates.
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TRA (Additive) DME 5.2.2 (Long Term Fuel Trim= LTFT):
Idle area, usually <1800 RPM~ (Can easily be remembered as “Around Town or Traffic”)
Measured in Fuel Ti ms (milliseconds)
Makes small adjustments
Looking for “0”
Negative numbers are when engine is running rich and ECU is taking away fuel.
Positive numbers are when engine is running lean and ECU is adding fuel.
Affected by FRA (You must adapt FRA first)
RKAT (Additive) DME 7.2 on (LTFT):
Idle area <1800~ (Can easily be remembered as “Around Town or Traffic”)
Measured in % of Ti
Makes small adjustments
Looking for approximately 0%
Negative numbers are when engine is running rich and ECU is taking away fuel.
Positive numbers are when engine is running lean and ECU is adding fuel.
Affected by FRA (You must adapt FRA first)
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FRA (Multiplicative) DME 5.2.2: (Long Term Fuel Trim=LTFT):
Cruise area, usually >1800~ RPM (Can easily be remembered as “Freeway”)
Measured in % of Ti
Looking for “1%” showing the Ti multiplier
Numbers less than ‘1” are when engine is running rich and ECU is taking away fuel.
Numbers over ‘1” are when engine is running lean and ECU is adding fuel.
FRAU [Under] & FRAO [Over] (Multiplicative) DME 7.2 on: (LTFT):
Cruise area, usually >1800~ RPM (Can easily be remembered as “Freeway”)
Measured in % of Ti
Looking for “1%” showing the Ti multiplier
Numbers less than ‘1” are when engine is running rich and ECU is taking away fuel.
Numbers over ‘1” are when engine is running lean and ECU is adding fuel.
ME Version | Rich | Nominal | Lean | ||
ME5.2 | TRA | -0.400 | 0.00 | 0.400 | Idle (ms) |
| FRA | 0.70% | 1.00 | 1.30% | Cruise | |
| ME5.2.2 | |||||
| TRA | -0.400 | 0.00 | 0.400ms | Idle (ms) | |
| FRA | 0.70% | 1.00 | 1.30% | Load | |
| ME7.2 | |||||
| RKAT | -6.0% | 0.0% | 6.0% | Idle | |
| FRAU | 0.70% | 1.00 | 1.30% | Load lower range | |
| FRAO | 0.70% | 1.00 | 1.30% | Load upper range | |
| ME7.8 | |||||
| RKAT | -6.0% | 0.0% | 6.0% | Idle | |
| FRAU | 0.70% | 1.00 | 1.30% | Load lower range | |
| FRAO | 0.70% | 1.00 | 1.30% | Load upper range | |
| ME7.8_40 | |||||
| RKAT | -6.5% | 0.0% | 6.0% | Idle | |
| FRAU | 0.70% | 1.00 | 1.30% | Load lower range | |
| FRAO | 0.70% | 1.00 | 1.30% | Load upper range |