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Problem using cam sensor inside Honda B serie distributor

Posted: Sun Nov 19, 2017 3:43 pm
by dreodim
Hello everybody,

I’ve got a problem about using the OEM honda distributor as a cam sensor.
Inside the OEM distributor, are 3 sensors.
One is the crank sensor (24 teeth without missing tooth)
Another one is the cam sensor (1 tooth)
The last one is not used (4 teeth, one for each TDC)
DTA document about wiring tell that are magnetic sensor, so pin 22 and 12 must be used.

Image

But I have a problem with using the cam sensor as a magnetic sensor.
Here is a picture of the crankshaft oscilloscope using crank and cam sensor as magnetic :

https://photos.app.goo.gl/zhw1eLdMJxvYCf4J3

You can see the cam signal is not good at all !

Then I tried to use it as hall sensor and it seems working
Here a picture of the crankshaft oscilloscope using cam as a hall sensor :

https://photos.app.goo.gl/aA8doKFmXznEw1Z92

But as Alex (from DTA) told me, It will not work a long time and with high RPM because this sensor only have 2 wires (a hall sensor must be powered so have 3 wires).

https://drive.google.com/file/d/1kIcHj8 ... sp=sharing

So I tried to understand what going wrong :

I thought my distributor could be damaged so I bought another one, a second hand but a Honda OEM one to be sure of what I have under my hands.
It did not work, so to be really sure, I found another one again, again a Honda OEM, and again it did not work ...

So I thought It could be my electric loom. I ad some wires to shunt the electric loom to be sure, and again it did not work (so my electric loom seems to be ok)
I also tried to commute ground and output but it did not work

A friend give me another DTA S60, and it did not work ...

I finally tried to modify the target of the sensor, grinding (yellow area) the metal to make a very distinctive tooth, but it did not work ...

https://photos.app.goo.gl/ppHpasx41qLPRERq2

So I need your help !
I don’t know what to do more !

Thank you

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 20, 2017 10:31 am
by stevieturbo
Alex can decypher the DTA cam scopes better. I can never make much sense of them !!

A proper scope trace would be easier. But the first image looks like you're getting far more than one tooth, so are you sure you're in the correct wiring pair for that trigger ?
And polarity correct ?

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 20, 2017 2:12 pm
by dreodim
yes I tried every thing
something very interesting is that it look like working when I plugged it as a hall sensor but it is a magnetic sensor (without powering wire)

And the magnetic sensor of crank is working good but not the cam sensor ...

I really don't understand what can I do more ....

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 20, 2017 3:09 pm
by stevieturbo
A true scope trace of each sensor would be very helpful here. I believe each sensor has its own dedicated wiring pair ?

I did a B16A many years ago on another ecu, but I was able to get good clean scope traces on each of the triggers

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Sat Nov 25, 2017 5:16 pm
by dreodim
hi,

As is speak with Alex, I cannot have a true scope so I decided to try using a standard Magneti Marelli sensor (SEN8) with homemade bracket to fit inside the OEM distributor housing.
Then I got a good crank oscilloscope on the DTA tool.

So I'm designing a good bracket and I will adapt a 36 tooth crank wheel to avoid using the OEM sensor.

I have a technical question about the crank sensor when it see the tooth
the true signal is made by the center of the tooth (top2) or by the first ridge of the tooth (top1) or by the end of the tooth (top3)

Image

Between the top 1 and top 2, with a 36 tooth crank wheel it represent 5° so I'm curious about how it works.

Many thanks

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Sun Nov 26, 2017 5:53 am
by Alex DTA
Either 1 (rising edge) or 3 (falling edge), never 2, depending on the ECU. Some use both 1 and 3 in certain situations.
DTA uses 3 for the crank, and either 1 or 3 for the cam.

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Sun Nov 26, 2017 7:27 am
by stevieturbo
With a VR, magnetic sensor, falling edge usually makes most sense.

With a Hall sensor, it can really vary with the sensor used. Some will switch faster with rising, some with falling, and it's a good clean "switch" you want with such a sensor.

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 27, 2017 4:54 am
by adamw
Alex DTA wrote:Either 1 (rising edge) or 3 (falling edge), never 2, depending on the ECU. Some use both 1 and 3 in certain situations.
DTA uses 3 for the crank, and either 1 or 3 for the cam.
Are you sure? That sounds completely wrong to me. The OP is using a SEN8, which is a common Ford VR sensor. When using a VR input most ECU's will trigger at the zero-crossing which is the dead centre of the tooth. So the OP was correct in that "Top 2" is the trigger point.

Your rising edge/falling edge analogy also seems wrong if you were assuming a hall sensor? Hall sensors can be NPN or PNP type, nearly all I have come across in the automotive world are NPN. So the output goes low when a metal tooth approaches. From an ECU settings/waveform perspective, "Top1" would be a falling edge and "Top3" would be a rising edge.

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 27, 2017 5:21 am
by stevieturbo
It would be interesting to see both a VR and Hall mounted on the same wheel, in identical locations.

Certainly on VR the "fall" is initiated by the falling edge of the tooth...but as you say, this may not actually be considered the actual trigger point which will be some time period after it depending where the crossing point to register a trigger actually is.

Re: Problem using cam sensor inside Honda B serie distributo

Posted: Mon Nov 27, 2017 8:53 am
by Alex DTA
adamw wrote:
Alex DTA wrote:Either 1 (rising edge) or 3 (falling edge), never 2, depending on the ECU. Some use both 1 and 3 in certain situations.
DTA uses 3 for the crank, and either 1 or 3 for the cam.
Are you sure? That sounds completely wrong to me. The OP is using a SEN8, which is a common Ford VR sensor. When using a VR input most ECU's will trigger at the zero-crossing which is the dead centre of the tooth. So the OP was correct in that "Top 2" is the trigger point.

Your rising edge/falling edge analogy also seems wrong if you were assuming a hall sensor? Hall sensors can be NPN or PNP type, nearly all I have come across in the automotive world are NPN. So the output goes low when a metal tooth approaches. From an ECU settings/waveform perspective, "Top1" would be a falling edge and "Top3" would be a rising edge.
You're right. I've looked at the picture, and assumed the drawing on the right is the scope trace, i.e. a Hall effect trace.
I see now it's meant to be a representation of the teeth going past the sensor.

BTW, the SEN8 is the Marelli magnetic sensor, which has the opposite polarity to the Ford sensor.