nissan200sx.dk Posted April 11, 2014 Report Share Posted April 11, 2014 Hi all.. When I record audio from my knock sensors through vi-pec digital knock box, I get A LOT of generator noise. High pitch tone that rises whit engine rpms. Where should i begin fixing this? Quote Link to comment Share on other sites More sharing options...
Dave Kriedeman Posted April 11, 2014 Report Share Posted April 11, 2014 Hi, make sure your knock sensor wiring is away from all ignition sources. How have you configured the Knock amplifier as far as your noise filters etc. Have you used this device previously without issue or have you just started to use the device. Regards Dave. Quote Link to comment Share on other sites More sharing options...
nissan200sx.dk Posted April 11, 2014 Author Report Share Posted April 11, 2014 The knock sensor wires are away form ignition sources. But just to be sure, what are considered as being part of an ignition source? Power for ignition? Ground for ignition? Wires that go to from ECU to ignition amplifier? Wires form ignition amplifier to coils? Have used it for a couple of years or so, with no issues, but after I made the conversion to 4x4, and a new engine wiring loom ive had generator noise. Should the ground and power wires for knock box be seperate to rest of wiring? Thank you Ronni. PS. thanks for the help with injectors. Quote Link to comment Share on other sites More sharing options...
Dave Kriedeman Posted April 12, 2014 Report Share Posted April 12, 2014 Hi Ronni, the ignition source I am referring to can be the ignition outputs from the ecu to the ignition module or the coil trigger wires from the ignition module to the coils, or close to the coils themselves. Also if the wiring for the knock sensors runs near any large positive feed wires that will carry alternator charge current, charge wire from alternator to battery etc. Are your knock sensor cables shielded cable, only grounded at one end. Also you say you have made a new loom and added to 4x4. Recheck your knock sensor looms, but also you may have to reconfigure your filters etc. I am assuming by saying you have converted to 4x4 that you are using a GTR sump and front transaxle assembally. This will generate new noise and harmonics through the block and obviously into the knock sensors. Something to consider. Forgot to add, do you have a condenser (noise suppressor) on the alternator, from charge output to ground of the alternator. Also check you are not running parallel with your trigger wires (CAS). PWM outputs, injectors, idle solenoid, boost solenoids, etc, wiring loom repositioning near any frequency generating device can cause issues. Power and Earth for the amplifier can be shared from the ecu power supply if you wish or separate. Regards Dave. Quote Link to comment Share on other sites More sharing options...
nissan200sx.dk Posted April 12, 2014 Author Report Share Posted April 12, 2014 Hi Dave. Thank you! There is alot of things I can change. Thanks for the help with all the potential wiring problem I need to have a look at. My GTR sump and front transaxle, will that change the knock frequency? Or will it just add different noises to the recording? Quote Link to comment Share on other sites More sharing options...
Dave Kriedeman Posted April 12, 2014 Report Share Posted April 12, 2014 Hi, it will add extra noise that you may need to filter out. Regards Dave. Quote Link to comment Share on other sites More sharing options...
nissan200sx.dk Posted April 20, 2014 Author Report Share Posted April 20, 2014 Hi Dave. Have done all the things now, and still have a little generator noise. It helped a lot, but some are still there. Quote Link to comment Share on other sites More sharing options...
Dave Kriedeman Posted April 20, 2014 Report Share Posted April 20, 2014 Hi, so the noise you are talking about, is it best described as a high pitch squeal or a buzzing type sound. Did you recalibrate your settings in the ViPEC Knock module. Also there is software you can download for the ViPEC Knock module called Shock Wave from memory, the audio captured from the Knock module gets analysed via Shock wave. If you download the users manual for the knock module it has all the info in there about it. Just out of curiosity, do you have all of your ECU earths going to the engine block, they should also be grounded to the block at different points. However I have paired V88 earths to the engine block for years without issues.(2 earths together at 1 point and the other pair at a different earth point). Make sure that you have a good earth from battery negative to the chassis and from battery negative to the engine bock. Then I also run an earth from the bock to the chassis. You should aim for as close as possible to 0 ohms between the battery negative and the engine block and the block to the chassis. Also test these same points in DC VOLTS. You want to see less than 1 volt. Try powering the Knock module from a separate power source and use a separate earth. Also check that the Knock module wires between the Knock module and the ECU aren't exposed to other signal wiring around the ECU itself. Regards Dave. Quote Link to comment Share on other sites More sharing options...
nissan200sx.dk Posted April 21, 2014 Author Report Share Posted April 21, 2014 Thank you Dave, will try those things. The noise is a high pitched squeal. I use wavepad sound editor, as the manual. Recalibrate knock box? I have checked the output so its between 1 and 2 volts. The knock frequency will that change also? Quote Link to comment Share on other sites More sharing options...
Dave Kriedeman Posted April 21, 2014 Report Share Posted April 21, 2014 Hi, knock frequency is normally a product of cylinder and bore size. You could try changing this value but I don't believe it will help. Regards Dave. Quote Link to comment Share on other sites More sharing options...
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