2gbaroinputworkaround
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2gbaroinputworkaround [2012/07/02 08:58] twdorris |
2gbaroinputworkaround [2012/07/05 13:25] 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 aftermarket sensors. The 2G ECU has a 3.3K ohm pull-down resistor (R39 on 1995 EPROM ECUs), which may (probably will) put more load on the sensor than it can drive properly. | + | 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. | 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. | ||
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| ====== Process ====== | ====== Process ====== | ||
| - | If you're really looking to maximize inputs, you can consider removing R39 from the underside of the ECU board. **NOTE:** This is ONLY appropriate for a 1995 EPROM ECU. It does not work on 96/97 ECUs. A different resistor may be present on 96/97 ECUs that can be removed like the 95 EPROM ECUs, but we have not spent any time yet trying to identify it. | + | If you're really looking to maximize inputs, you can consider removing R39 from the underside of the ECU board. |
| It's best to use a couple small-tip soldering irons for this. Heat 'em up, apply one to each side of the resistor and slide it right off. I'm including a picture of the location of the resistor of interest below. I have verified that this does allow a GM 3bar to drive the baro input just fine. Once you have done that, you can use either the baro or the intake air temp inputs for whatever you want. | It's best to use a couple small-tip soldering irons for this. Heat 'em up, apply one to each side of the resistor and slide it right off. I'm including a picture of the location of the resistor of interest below. I have verified that this does allow a GM 3bar to drive the baro input just fine. Once you have done that, you can use either the baro or the intake air temp inputs for whatever you want. | ||
2gbaroinputworkaround.txt ยท Last modified: 2024/03/15 11:16 (external edit)
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