oversteer Posted September 24, 2019 Report Share Posted September 24, 2019 Hello I have taken a trigger scope of the car, pretty sure setup to use on subaru with these reluctor sensors is falling, however I am unsure of sensor polarity as i have them arranged in a non standard fashion, can anyone tell from the trigger scope if the signal is indeed falling ? or do i need to reverse the wires on the sensor ? Cheers Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 24, 2019 Report Share Posted September 24, 2019 Both cam and crank are incorrect polarity, you will need to swap +/- wires. Post another scope once they are swapped because your wave form is quite distorted which suggests there may be some other wiring problem too. It may come right once swapped though. Quote Link to comment Share on other sites More sharing options...
oversteer Posted September 24, 2019 Author Report Share Posted September 24, 2019 Swapped the wires and it looks right now, I'm cranking engine with plugs in and not the strongest battery(120-130rpm in link).....and it sounds like every cylinder doesn't have the same compression(not sure why...).... that would be the reason for the uneven wave form i'd say ! Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 24, 2019 Report Share Posted September 24, 2019 1 hour ago, oversteer said: Swapped the wires and it looks right now, I'm cranking engine with plugs in and not the strongest battery(120-130rpm in link).....and it sounds like every cylinder doesn't have the same compression(not sure why...).... that would be the reason for the uneven wave form i'd say ! You've got a waveform that is probably usable, but it is not as symmetrical as it should be. It may improve when its running, but it looks like there is something else connected to the trigger circuit that shouldnt be. Like maybe there is a bad ground or the ground is shared with something. You often see this type of deformation with piggyback installs for instance. Still it will likely run as it is... Quote Link to comment Share on other sites More sharing options...
oversteer Posted September 24, 2019 Author Report Share Posted September 24, 2019 Ok i see what you mean about it being symmetrical ..... trigger grounds come from A-24 Gnd out, which is shared with APS, TPS,, pressure sensors(MAP, OP, FP, Crankcase, Exh left and right) and 4 Temp sensors(ETS, IAT, Oil, IC coolant)...... that is a lot a stuff of that sensor ground, is there a better way of doing it ? Loom B-22 has gear position and shift knob on it....D-5 has FP current sensors.. Looking at this FSM wiring diagram, the factory sensor ground goes to "Joint connector A, on 2nd page" and then to everywhere and everything.... BPBL5 3.0 Engine Wiring.pdf Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 24, 2019 Report Share Posted September 24, 2019 That sounds fine. Provided all the other sensors read ok once running I wouldnt worry about it. Quote Link to comment Share on other sites More sharing options...
Knox Posted March 9, 2021 Report Share Posted March 9, 2021 On 9/24/2019 at 8:09 AM, Adamw said: Both cam and crank are incorrect polarity, you will need to swap +/- wires. Post another scope once they are swapped because your wave form is quite distorted which suggests there may be some other wiring problem too. It may come right once swapped though. Hello Ademw, how can I understand if the signal wires polarity +/- wires are incorrect or correct? Because of I forgot to take my notebook with me I can not attach a trigger scope but may be you can explain it to me with using the above triggerscope pictures. Thank you. Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 9, 2021 Report Share Posted March 9, 2021 Basically the straightest most vertical edge should fall through zero. Sometimes it is not easy to spot on multitooth wheels with very closely spaced teeth but it is definitely clear in the pictures above. Wiring info from the help file below showing example of correct and incorrect polarity. Quote Link to comment Share on other sites More sharing options...
Knox Posted March 10, 2021 Report Share Posted March 10, 2021 9 hours ago, Adamw said: Basically the straightest most vertical edge should fall through zero. Sometimes it is not easy to spot on multitooth wheels with very closely spaced teeth but it is definitely clear in the pictures above. Wiring info from the help file below showing example of correct and incorrect polarity. This is on honda b18c engine with t1r cam gear sensor kit. There is dual pole one sensor (hall). Engine start and works but I think one of the sensor I wired wrong (+/-) because both uses falling edge on calibration but on trigger scope trig1 signal rise and fall and cam sensor is opposite it fall and rise on triggerscope. May be it is because of dual pole one sensor and I wired correct but I can not be sure thats why I asked. Trigger Scope Log 2021-03-9 5;04;04 pm.llg Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 10, 2021 Report Share Posted March 10, 2021 Polarity is only relevant for reluctor/VR sensors. Most hall effect sensors will work equally well rising or falling. A general rule for hall sensors is to choose the edges on trig1/2 that are not close to each other. Some specific hall effect sensors have one edge that will be slightly more accurate, but it is usually minimal. Quote Link to comment Share on other sites More sharing options...
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