SPP Posted November 27, 2020 Report Share Posted November 27, 2020 I am looking to use a Atom as a piggyback for a basic add-on port injection system with two injectors. Is it possible to wire it to an ignition coil trigger off the stock engine harness or do I need to tap into the factory cam and crank on the vehicle? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 27, 2020 Report Share Posted November 27, 2020 Typically the signal on the primary side of the coil would not be suitable as a trigger as it is not just an on/off signal like you may expect - once the plug fires you have a whole lot of voltage "ringing" or oscillation coming back out of the primary - so the ecu would see some of these oscillations and it will mess up your RPM calculation. What engine are we talking? What does it have driving the ignition coil? - i.e is the an ignition module/ignitor or is it all a sealed distributor/trigger/ignitor/coil all in one type thing? It may be possible to get a signal from the crank or cam, or maybe the input side of the ignitor but really need more info on what we are working with. Quote Link to comment Share on other sites More sharing options...
SPP Posted November 27, 2020 Author Report Share Posted November 27, 2020 11 minutes ago, Adamw said: Typically the signal on the primary side of the coil would not be suitable as a trigger as it is not just an on/off signal like you may expect - once the plug fires you have a whole lot of voltage "ringing" or oscillation coming back out of the primary - so the ecu would see some of these oscillations and it will mess up your RPM calculation. What engine are we talking? What does it have driving the ignition coil? - i.e is the an ignition module/ignitor or is it all a sealed distributor/trigger/ignitor/coil all in one type thing? It may be possible to get a signal from the crank or cam, or maybe the input side of the ignitor but really need more info on what we are working with. Thank you for the quick response. The car in question is an Audi with a 4.0T V8. It uses a “smart” coil, with a 4 wire hookup. The CAM may be the best bet as I’ve read the CRANK trigger is fairly complex. Let me know your thoughts. Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 27, 2020 Report Share Posted November 27, 2020 Yeah, one of the cam sensors will be the best option. They have 2 long teeth and 2 short teeth, but the falling edges are evenly spaced so that will work. In the ECU set up, set number of cyl to 4, set trigger mode to 1 tooth per TDC, set trig 1 to opto/hall and turn the pull-up off. Set trig 2 sync mode to none. Quote Link to comment Share on other sites More sharing options...
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