Hello
I read from http://www.DIYAutoTune.com/tech_article ... led_vw.htm MegaSquirt-II PCBv3.0 Mods Required. And there is that you'll need a 1K pull-up resistor from the 5 volts in the proto area to TachSelect but there is no such thing mentioned in megamanual assembly guide for the V3 main board. So which way is the right way?
Hall effect input circuit
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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Bernard Fife
- Master Squirter
- Posts: 475
- Joined: Thu Oct 29, 2009 12:54 pm
Re: Hall effect input circuit
ignasio,
Some Hall sensors have the pull-up built in, others do not. It seems the DIYAutoTune has determined that your sensor (for a water cooled VW, according to the link) does not have a pull-up, so they suggest you add it.
Lance.
Some Hall sensors have the pull-up built in, others do not. It seems the DIYAutoTune has determined that your sensor (for a water cooled VW, according to the link) does not have a pull-up, so they suggest you add it.
Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it.” - George Bernard Shaw
Re: Hall effect input circuit
IIRC, it depends on the hall effect sensor. Some are three wire types which take +12v and ground with an output - that wouldn't need the pull up resistor. Two wire types likely would.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Re: Hall effect input circuit
My hall sensor have three wires so the megamanual circuit is ok no need for extra resistor. Thanks for responding. 
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Bernard Fife
- Master Squirter
- Posts: 475
- Joined: Thu Oct 29, 2009 12:54 pm
Re: Hall effect input circuit
Ignasio,
All Hall resistors have 3 wires - power, ground, and signal - plus possibly a shield wire for the harness. It is VR sensors that have 2 wires.
So having 3 wires is no indication of whether you need a pull-up or not (though if you are following DIY's guide and it applies to your vehicle, then I suspect you do need a pull-up - they don't just make that stuff up!).
If the Hall sensor already has a pull-up, then you will consistently find a significant voltage (usually 5, 8, or 12V) on the signal at some point in the rotation of the wheel while the sensor is powered up. If the sensor does not have an internal pull-up, the signal will "float" near ground, and likely remain fairly low (generally under 1 Volt, and it won't depend in the crank wheel position).
Lance.
All Hall resistors have 3 wires - power, ground, and signal - plus possibly a shield wire for the harness. It is VR sensors that have 2 wires.
So having 3 wires is no indication of whether you need a pull-up or not (though if you are following DIY's guide and it applies to your vehicle, then I suspect you do need a pull-up - they don't just make that stuff up!).
If the Hall sensor already has a pull-up, then you will consistently find a significant voltage (usually 5, 8, or 12V) on the signal at some point in the rotation of the wheel while the sensor is powered up. If the sensor does not have an internal pull-up, the signal will "float" near ground, and likely remain fairly low (generally under 1 Volt, and it won't depend in the crank wheel position).
Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it.” - George Bernard Shaw
Re: Hall effect input circuit
Actually, I have Audi but DIYAutoTune don't cover it. Audi and VW engines and electric systems are basically the same, the older models at least were. Thanks for explaining now I know how to proceed.