2gbaroinputworkaround
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision | Next revision Both sides next revision | ||
|
2gbaroinputworkaround [2009/09/06 08:03] twdorris |
2gbaroinputworkaround [2012/07/02 08:57] twdorris |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ====== 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), 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. | + | 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. |
| - | 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. | + | 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 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. | ||
| + | |||
| + | **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. | ||
| The 1G baro input doesn't seem to suffer from this problem. It has an input impedance similar to the 2G MDP sensor input's 100K ohms). | The 1G baro input doesn't seem to suffer from this problem. It has an input impedance similar to the 2G MDP sensor input's 100K ohms). | ||
| Line 9: | Line 15: | ||
| **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]]. | ||
| - | **09/06/2009:** If you happen to already have our GM MAF cable on your car, you can safely use the baro break-out of that cable because it has a built-in buffer circuit. Details are on the [[gmmafiatbaro|GM MAF Cable page]]. | ||
| ====== Process ====== | ====== Process ====== | ||
2gbaroinputworkaround.txt · Last modified: 2024/03/15 11:16 (external edit)
Page Tools
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Share Alike 4.0 International
