SOURCE
https://www.eng-tips.com/viewthread.cfm?qid=274309
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QUESTION
I have a new ECU that I’m wiring to an engine with a significant number of sensors. Each 3 wire) sensor needs to be supplied with a 5v signal from the ECU. Since I cant wire them all individually in to the one output pin of the ECU, what would be the simplest method for connecting them all? I’m hesitant to run a wire all the way to each sensor and tie the in to common block fed by the ECU as that doesn’t seem too elegant. I guess I could piggy back with the lead going to one sensor then another and so on and so forth. Is there a common practice?
REPLIES
jbkettler
First - to answer your question directly - the most elegant is going to be to start with a single connection at the ECU and install a splice pack with a lead going to each sensor from that. Put the splice in a central location to the sensors it feeds. This splice can then be properly sealed to minimize degradation of the connection. A terminal block typically referes to an open to atmosphere connection point with screwed connections - good for quick and dirty (i.e. a quick hookup to make sure everything works before final fabrication of a wire harness - maybe what you should do with the prototype), not so great for long term and open to environment.
In addition - The 5V output from the ECU should have a maximum rating (probably reported as maximum amps). Do not exceed this. Each of your sensors will consume some amount of power. You can power multiple sensors as long as their current consumption does not exceed the rated output of the 5V channel (Most 3 wire sensors consume very little power - but also most 5V references are only good to about 1 amp - on stock OEM ECU’s). If the ECU has multiple 5V references, divide the sensors up logically between them.