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ecuinputdata [2009/02/22 09:26]
dmertz
ecuinputdata [2024/03/15 11:16] (current)
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 ====== ECU Input Impedance Mismatch ====== ====== ECU Input Impedance Mismatch ======
  
-There are a number of analog inputs available on the 1G and 2G ECU.  Many are used for critical engine operation, but some are available for datalogging [[ExternalSensorList|aftermarket sensors]]. ​ The problem is that some of these inputs are incompatible with some aftermarket sensors. ​ In particular, the 1G EGR temperature input and the 2G baro input have pull up/pull down resistor configurations that some sensors are not capable of driving properly. ​ The solution to this is to "​buffer"​ the input so that the sensor is not directly driving the ECU's input. ​ The circuit and buffer board described below can be used for this purpose. ​ The picture below illustrates the buffer board available for purchase from ECMTuning. 
  
-{{http://www.ecmtuning.com/​images/​forums/typicalinstall.gif}}+There are a number of analog inputs available on the 1G and 2G ECU. Many are used for critical engine operation, but some are available for datalogging [[:externalsensorlist|aftermarket sensors]]The problem is that some of these inputs are incompatible with some aftermarket sensorsIn particular, the 1G EGR temperature input and the 2G baro input have pull up/pull down resistor configurations that some sensors are not capable of driving properly.
  
-**12/​19/​2007:​** We are now accepting orders for these completed units. ​ We have several in stock, ready to ship. 
  
-http://www.ecmtuning.com/​product_info.php?​cPath=26&​products_id=39+The solution to this is to "​buffer"​ the input so that the sensor is not directly driving the ECU's inputThe circuit and buffer board described below can be used for this purposeThe picture below illustrates the buffer board available for purchase from ECMTuning.
  
  
 +{{https://​www.ecmtuning.com/​images/​forums/​typicalinstall.gif?​direct&​}}
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 +**01/​01/​2013:​**Due to low demand, we've decided to discontinue this product. ​ Many common sensors now include this type of functionality internally, negating the need for this board. ​ The Omni 4-bar sensor that we sell on our website, for example, has this functionality built in.  Most, if not all, wideband kits these days do too.
  
 ====== Connections ====== ====== Connections ======
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 Connect "GND to ECU" to the ECU's sensor ground, pin 24 (Green/​Black) on a 1G ECU or pin 92 (Black) on a 2G ECU.  This is also present under the hood at the MAF, TPS, MDP and coolant temp sensors. Connect "GND to ECU" to the ECU's sensor ground, pin 24 (Green/​Black) on a 1G ECU or pin 92 (Black) on a 2G ECU.  This is also present under the hood at the MAF, TPS, MDP and coolant temp sensors.
  
-If the sensor is a 5V sensor that draws little current, like a MAP sensor, connect the sensor'​s power, signal and ground connections to the input side of the buffer circuit assembly. If the sensing device, such as a wideband, has its own power and ground, connect only the sensing device'​s signal wire to the input side of the buffer. ​Insulate ​any unused wires.+If the sensor is a 5V sensor that draws little current, like a MAP sensor, connect the sensor'​s power, signal and ground connections to the input side of the buffer circuit assembly. If the sensing device, such as a wideband, has its own power and ground, connect only the sensing device'​s signal wire to the input side of the buffer. ​In either case, you still must provide +5V and GND to the buffer circuit and you must then insulate ​any unused wires.
  
  
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 In either case (1G or 2G) and for just about any input, you can also consider using a unity buffer to drive the ECU.  Such a device presents a low-load input for connecting the external sensor and then produces a higher drive output for connecting to the ECU's input. ​ The following schematic can be used to build this device. In either case (1G or 2G) and for just about any input, you can also consider using a unity buffer to drive the ECU.  Such a device presents a low-load input for connecting the external sensor and then produces a higher drive output for connecting to the ECU's input. ​ The following schematic can be used to build this device.
  
-{{http://​www.ecmtuning.com/​images/​forums/​Buffer.JPG|Diagram}}+{{https://​www.ecmtuning.com/​images/​forums/​Buffer.JPG|Diagram}}
  
 Note that this is not necessarily an easy thing to do.  The op-amp part referenced in that diagram is extremely small and difficult to work with if you're not familiar with SMT techniques or have access to appropriate equipment.  ​ Note that this is not necessarily an easy thing to do.  The op-amp part referenced in that diagram is extremely small and difficult to work with if you're not familiar with SMT techniques or have access to appropriate equipment.  ​
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 If you can't wait and working with a SOT23-5 package is just too small for you, then consider this circuit/​chip instead. ​ It's a bit easier to work with. If you can't wait and working with a SOT23-5 package is just too small for you, then consider this circuit/​chip instead. ​ It's a bit easier to work with.
  
-{{http://​www.ecmtuning.com/​images/​forums/​BufferDIP.JPG|Diagram}}+{{https://​www.ecmtuning.com/​images/​forums/​BufferDIP.JPG|Diagram}}
  
ecuinputdata.1235312764.txt.gz ยท Last modified: 2009/02/22 09:26 by dmertz