2gbaroinputworkaround
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2gbaroinputworkaround [2012/07/02 08:57] twdorris |
2gbaroinputworkaround [2024/03/15 11:16] (current) |
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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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| Short of removing that resistor 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 that resistor 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. | ||
| - | **OMNIPOWER NOTE:** The [[http://www.ecmtuning.com/product_info.php?cPath=28_30&products_id=47|OmniPower 4-bar sensor]] that we sell on our website *does* work fine on the 2G baro input. This sensor incorporates a buffer circuit that drives the 2G baro input just fine. | + | **OMNIPOWER NOTE:** The [[https://www.ecmtuning.com/product_info.php?cPath=28_30&products_id=47|OmniPower 4-bar sensor]] that we sell on our website *does* work fine on the 2G baro input. This sensor incorporates a buffer circuit that drives the 2G baro input just fine. |
| **GM MAF CABLE NOTE:** Also note that our GM MAF cable's "baro" [[gmmafiatbaro|breakout wire]] includes a buffer circuit as well. So any sensor connected to a GM MAF cable's "baro" wire will work fine as well without having to deal with the 2G ECU's baro input resistor configuration. | **GM MAF CABLE NOTE:** Also note that our GM MAF cable's "baro" [[gmmafiatbaro|breakout wire]] includes a buffer circuit as well. So any sensor connected to a GM MAF cable's "baro" wire will work fine as well without having to deal with the 2G ECU's baro input resistor configuration. | ||
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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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| ====== Process ====== | ====== Process ====== | ||
| - | If you're really looking to maximize inputs, you can consider removing R39 from the underside of the ECU board. 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. | + | If you're really looking to maximize inputs, you can consider removing R39 from the underside of the ECU board. |
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| + | 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. | ||
| - | {{http://www.dsmlink.com/images/forums/2gbaro.jpg}} | + | {{https://www.ecmtuning.com/images/forums/2gbaro.jpg}} |
2gbaroinputworkaround.1341233839.txt.gz · Last modified: 2012/07/02 08:57 by twdorris
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