Issue with Dual VR 2.0

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Issue with Dual VR 2.0

Postby VR6TA4 » Sat Nov 12, 2011 10:11 pm

I just received the board today. I hooked it up for testing, at first I would just getting a very fast constant crank count with the ignition just on acc. I hadn't even tried it yet, now I am not getting any reading at all. Are familiar with this behavior?
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Re: Issue with Dual VR 2.0

Postby jbelanger » Sat Nov 12, 2011 11:11 pm

First, I just split this post just to make it easier to follow.

You need to put a bit more details about your setup: what hardware are your running and how did you connect the board to it and how did you connect the sensor to the board? And are you saying that just turning on power will generate a tach signal? If so, do you have anything else running that could generate noise when you see this? And are you running shielded wires from the sensor to the board?

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Re: Issue with Dual VR 2.0

Postby VR6TA4 » Sun Nov 13, 2011 5:03 am

The first time I turned it on, it was generating a tach/crank signal. Now I am getting nothing. I have VR + and - from crank sensor running to the board. I have ground and +12V coming from the ecu from a HS output and sensor ground output and I have both shielding grounds tied to the sensor ground/ground connection on the board. I can measure +12volt on the board, ground gives me around 500 ohms from the connection to chassis ground and as long as power is applied to the board I am reading +5v at the 1 output connection. Later today, I will have my wife crank the car while I am measuring voltage @ output 1 so I can see if it is cycling between 5 and 0 volts. Thanks.
Last edited by VR6TA4 on Sun Nov 13, 2011 12:46 pm, edited 1 time in total.
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Re: Issue with Dual VR 2.0

Postby jbelanger » Sun Nov 13, 2011 11:51 am

Let me know what you see. You can also try to connect a LED at the output to see if it flashes with the input.

And I don't know how you measured the ground but 500 Ohms is a very high value. You should barely be able to measure any resistance between the different grounds.

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Re: Issue with Dual VR 2.0

Postby VR6TA4 » Sun Nov 13, 2011 2:33 pm

jbelanger wrote:Let me know what you see. You can also try to connect a LED at the output to see if it flashes with the input.

And I don't know how you measured the ground but 500 Ohms is a very high value. You should barely be able to measure any resistance between the different grounds.

Jean

Just tried it again, I am now reading about 34 ohms between ground and chassis ground. I had my daughter try the ignition while I measured voltage at output 1. It stayed at a constant 5v. Another thing, when power is applied to the board, I can measure +2.2V at VR+ and - at any time, is that normal? I am running out of ideas, do you have any thoughts? Thanks.
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Re: Issue with Dual VR 2.0

Postby jbelanger » Sun Nov 13, 2011 3:03 pm

Are you sure your sensor and wiring are ok? Can you try another sensor?

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Re: Issue with Dual VR 2.0

Postby VR6TA4 » Sun Nov 13, 2011 10:00 pm

At this point, I am willing to question everything. I think the wiring would be hard to be incorrect, there is only VR+ and -, power, ground and output. I pulled the VR sensor off my S4 motor to try it. It has the same wiring and it actually ohm-ed out about 20 ohms higher between pin2 and pin 3. Functionally it is the same, no crank signal to the seen at the ecu and I am still reading +2.2V on the pins of VR+ and VR- when power is applied with the S4 crank sensor. What should I be reading there when the engine is not cranking? Thanks.
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Re: Issue with Dual VR 2.0

Postby jbelanger » Mon Nov 14, 2011 7:16 pm

The reading you get at the input is normal for unconnected inputs. And since you see 5V at the output, it really looks like there is nothing getting to the input. If you have a way of generating a square wave signal (5V or 12V) then you could connect that either VR+ or VR- (and leave the other unconnected) and you should have an output. You could put a LED between the output and ground and if the signal is slow enough, you should see the LED blink.

Without having the board in my hand or without you being able to use an oscilloscope on it, it is very difficult to say what could be wrong. The voltages you see are normal for a powered up working board that doesn't have anything connected to it. So I can't tell if the problem is that there is no signal coming in or a problem with the board.

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