2gbaroinputworkaround
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2gbaroinputworkaround [2009/08/27 05:27] twdorris |
2gbaroinputworkaround [2009/09/06 08:03] twdorris |
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| ====== 2G Baro Input Workaround ====== | ====== 2G Baro Input Workaround ====== | ||
| - | The baro input of the 2G ECU may not be compatible with various the aftermarket sensors. The 2G ECU has a 3.3K ohm pull-down resistor (R39). This may put more load on the sensor than it can tolerate and still put out a proper signal. For example, a GM 3-bar sensor can only drive this input to 1.76 volts at maximum pressure. The new Delphi sensor seems to have a bit lower output impedance and will drive the 2G baro input to a little higher voltage at maximum sensor pressure, but it's still unsuitable. | + | The baro input of the 2G ECU may not be compatible with aftermarket sensors. The 2G ECU has a 3.3K ohm pull-down resistor (R39), which may (probably will) put more load on the sensor than it can drive properly. For example, a GM 3-bar sensor can only drive this input to 1.76 volts at maximum pressure. The GM 3.3-bar sensor seems to have a bit lower output impedance and will drive the 2G baro input a little higher, but it's still unsuitable. |
| Short of removing R39 from the ECU (described below), the 2G baro input is suitable for use only with very low impedance sensors (even a 50-ohm output impedance will produce a little over 1% of voltage offset). Since most sensor designs have a resistor in series with its output for protection, the 2G ECU's baro sensor input is probably not suitable for use with most sensors. | Short of removing R39 from the ECU (described below), the 2G baro input is suitable for use only with very low impedance sensors (even a 50-ohm output impedance will produce a little over 1% of voltage offset). Since most sensor designs have a resistor in series with its output for protection, the 2G ECU's baro sensor input is probably not suitable for use with most sensors. | ||
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| **12/19/2007:** Instead of this process, you can also consider using the [[ECUInputData|buffer circuit]]. | **12/19/2007:** Instead of this process, you can also consider using the [[ECUInputData|buffer circuit]]. | ||
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| + | **09/06/2009:** If you happen to already have our GM MAF cable on your car, you can safely use the baro input of that cable because it has a built-in buffer circuit. Details are on the [[gmmafiatbaro|GM MAF Cable page]]. | ||
| ====== Process ====== | ====== Process ====== | ||
2gbaroinputworkaround.txt ยท Last modified: 2024/03/15 11:16 (external edit)
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