Adzn3k Posted April 25, 2017 Report Share Posted April 25, 2017 I'm fitting a fuel pressure sensor to my fuel rail and the sensor I have will need a 1k pull up resistor would a 1 watt resistor be what I need? Quote Link to comment Share on other sites More sharing options...
Brad Burnett Posted April 25, 2017 Report Share Posted April 25, 2017 1/4 to 1/2 watt should be sufficient. Just curious what sensor you are using that would need a pull up for pressure. Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted April 25, 2017 Author Report Share Posted April 25, 2017 It's a 2 pin 0-10 bar sensor. Looks like this: http://www.ebay.co.uk/itm/381295911794 Quote Link to comment Share on other sites More sharing options...
Brad Burnett Posted April 25, 2017 Report Share Posted April 25, 2017 I would honestly replace that sensor with something more like thishttps://milspecwiring.com/store/index.php?route=product/product&path=47_316_51&product_id=475 Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 26, 2017 Report Share Posted April 26, 2017 The old 2 wire "VDO type" pressure sensors are not much good in a modern environment. I think originally they were probably designed to be powered by gauges with 12V pull ups built in. Their resistance is very low, something like 0-185ohms. So if you use say a 1k pull up to 5v your full scale signal output will only be something like 0-0.7V. To expand that resolution you need a much lower pullup - something like 20ohms will make it output 0-4.5V full scale, but the problem then is when it is at 0ohms that thing is gonna to pull about 250mA of current. The ECU power supply can only provide about 400mA total and that's got to power all other sensors, TPS, MAP, temps etc so you will be wasting 2/3 of your power on just that one sensor.You can get genuine Honeywell 3 wire pressure sensors for <USD$40 if you shop around so I would suggest re-thinking this one. One example: http://www.mouser.com/ProductDetail/Honeywell/PX3AN2BS150PSAAX/?qs=sGAEpiMZZMvhQj7WZhFIAMbIIQV5NoTbL6isqunddabblqqeR%2f4hsw%3d%3d Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted April 26, 2017 Author Report Share Posted April 26, 2017 OK thanks I will buy one of these make life a bit more straightforward, is there a diagram on wiring these 3 pin ones up do I take a 5v feed from the ecu? Quote Link to comment Share on other sites More sharing options...
Explode64 Posted May 8, 2017 Report Share Posted May 8, 2017 Are the Brass pressure sensors in the link above any good for fuel pressure when running E85? or should the MLH stainless steel sensor be used? Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 9, 2017 Report Share Posted May 9, 2017 Are the Brass pressure sensors in the link above any good for fuel pressure when running E85? or should the MLH stainless steel sensor be used?I have had one used with e85 for many years with no drama yet. Some will tell you "brass" is susceptible to corrosion with damp E85 but I have never seen any corrosion on all the brass jets etc I see inside carburetors running E85. Quote Link to comment Share on other sites More sharing options...
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