12-15-2017, 10:33 AM
I will continue to assert that there may be more than one cause for idle symptoms.
Also, there is more than one possibility with the TPS:
1. ECM power output from A9 to TPS and MAP does not provide 5 vdc, +/- 0.25 vdc (rare)
2. Any of the three wires to/from TPS damaged (can be checked by resistance values, while wiggling wires)
3. Connector pins/sockets not properly mating (visual inspection, plus unplug/re-plug)
4. Internal contacts are damaged/dirty/surface of resistor has crud (remove TPS and spray contact cleaner inside, alternating with clean compressed air...may or may not work)
5. Resistor damaged (erratic voltage, rather than linear, from closed to open)
Voltage reads will tell a lot.
A poor/damaged connection can make or break with thermal expansion/contraction.
For Harley-Davidson Sportsters with nose cone ignition modules (ended in 2003), intermittent failure was/is common. Typically intermittant failure could be replicated by applying heat from a hairdryer to aid with the diagnosis.
A crack in the 4 way or 5 way vacuum hose connector could be affected by thermal expansion/contraction.
A loose intake hose (8 clamps) could be affected by thermal expansion/contraction.
Crud on the resistor, moved by wipers/contact could move.
If an IACV issue, crud may affect piston operation, even if the stepper motor is being properly driven by the ECM.
Max deserves credit for not only probing the IACV, adding LEDs and producing a video, but for thinking out loud about the TPS to share thoughts for discussion.
Not easy diagnosing by remote...it is very much limited by available input.
Also, there is more than one possibility with the TPS:
1. ECM power output from A9 to TPS and MAP does not provide 5 vdc, +/- 0.25 vdc (rare)
2. Any of the three wires to/from TPS damaged (can be checked by resistance values, while wiggling wires)
3. Connector pins/sockets not properly mating (visual inspection, plus unplug/re-plug)
4. Internal contacts are damaged/dirty/surface of resistor has crud (remove TPS and spray contact cleaner inside, alternating with clean compressed air...may or may not work)
5. Resistor damaged (erratic voltage, rather than linear, from closed to open)
Voltage reads will tell a lot.
A poor/damaged connection can make or break with thermal expansion/contraction.
For Harley-Davidson Sportsters with nose cone ignition modules (ended in 2003), intermittent failure was/is common. Typically intermittant failure could be replicated by applying heat from a hairdryer to aid with the diagnosis.
A crack in the 4 way or 5 way vacuum hose connector could be affected by thermal expansion/contraction.
A loose intake hose (8 clamps) could be affected by thermal expansion/contraction.
Crud on the resistor, moved by wipers/contact could move.
If an IACV issue, crud may affect piston operation, even if the stepper motor is being properly driven by the ECM.
Max deserves credit for not only probing the IACV, adding LEDs and producing a video, but for thinking out loud about the TPS to share thoughts for discussion.
Not easy diagnosing by remote...it is very much limited by available input.