effects of shorting a hall sensor

[mickeymarrows]

What would happen if I connected the signal wire from a hall sensor (camshaft position sensor) to 5v? Would this kill the sensor?

What are the symptoms of a dead sensor?

[billr]

Is this a sensor that uses a pull-up resistor, as opposed to a pull-down? If so, yes, there is a good chance it has been damaged. You can bench-test it to prove if it is definitely bad, but not that it is good for sure. The damage done may be subtle and not pop-up except under certain operating conditions of temperature, vibration, humidity, frequency, etc. I would test it by simply trying it with the engine, if it works OK then use it. However, if there is ever any sync-loss issues, toss that sensor as the first step in trouble-shooting.

[mickeymarrows]

Thanks Bill.

I'm using a JB Perf divider board and theres a pair of jumpers to select between normal and inverted for the opto sensor, I'd made the jumpers as short loops as I knew I wanted to attach scope probes, unfortuantly it appears they have been knocked so they touch which means the 5v supply is connected to both the + and the signal line on the hall sensor. Same thing for the opto, hopefully that can cope..

[billr]

Did you have both an opto and Hall sensor connected (at different times) with the mis-connection? Maybe I'm getting confused... are you concerned about damage to a sensor, or to the MS tach input?

[mickeymarrows]

Did you have both an opto and Hall sensor connected (at different times) with the mis-connection? Maybe I'm getting confused... are you concerned about damage to a sensor, or to the MS tach input?

Hi Bill,

The JB Perf board has a pair of jumpers that allow you to invert the signal between the hall sensor and the opto isolator.. fit them one way and the opto will produce a signal when the hall goes low, fit them the other way and the opto will produce a signal when the hall goes high.

By shorting the jumpers I applied 5v to both wires from the hall and both 'wires' to the opto isolator..

[billr]

Okay, I get it now. The "opto" is an opto-isolated output from the circuit, not an opto sensor. Since this was on a JB board, maybe JB will chime in on what the chances are that the board could get damaged. I have never even seen one.

[mickeymarrows]

This is for Jean..

I now have a working Hall Sensor.

However, the JB Perf divider board is not giving the output I expect.

135 teeth on flywheel
1 TDC notch in crank

JB Perf jumper set to divide by 3. I expected 135/3 =45. So set Tuner Studio to 'toothed wheel', 45 teeth, 1 missing tooth.

I appear to be getting 20-1 or 21-1

I've attached my MSQ and the tooth logger file..

Martin

[racingmini_mtl]

Please post a composite log. It is much easier to analyze than the tooth logger.

Jean

[mickeymarrows]

OK, a composite log will take time as I'm now feeding my daughter

What else does it give you? I have no other ignition capture signals other than the JB Perf board output to tsel

[mickeymarrows]

Hello Jean,

I did say a composite log would take a while....

[racingmini_mtl]

That confirms what was in the tooth log (but is easier for me to assess in the composite logger). Your setup is missing a lot of teeth as you can see in the composite log as the very long gaps. So there is either a problem with the VR sensor, the VR conditioner circuit, the CPU on the divider board or the connection to the MS.

The only way I can see is to use an oscilloscope and follow the signal through the whole chain.

Jean