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scan gauge 2, smarty, boost readings.


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So i noticed something kinda odd today. when i removed my smarty programming from my truck the boost reading on my scangauge at idle goes to like -2.3. then i reprogrammed the smarty and it went to 0 at idle. thinking i was seeing things i redid the process. uninstalled it yet again and the boost reading went back to -2.3 or there abouts at idle.


so what is the smarty doing? or do i have a sensor going bad.?

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Smarty doesn't modify the boost signal, at least nothing I have ever seen or heard. I read ~0.5psi of boost at idle/off tuned or not, there is no change.


One of the reasons that the Smarty only fueled to 44psi for years was the 100% stock readings off the MAP sensor. Now they modify the limiter, so it fully fuels but reads correctly.

There isn't a need or reason to modify  the signal, one of the benefits of a Smarty over POS Edge products.


If you are reading -2.3 psi of boost that means that either your MAP or IAT sensor is reading off. It should be ±1 psi of zero at idle or engine off, as both sensors should be reading near identical.


I cannot think of how the Smarty would even do that adjustment, as the SG2 should be taking MAP (absolute) minus IAT (absolute) for boost.


I would think its a coincidence, maybe something with ECM programming and rebooting... but I don't think it has anything to do with Smarty programming.


There is a way in the ECM to adjust the sensor voltage vs value, but it would make it less accurate with the OEM senders and there is no reason for it especially at idle.

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The smarty is the latest software. it is reproducible. i Just flashed and unflashed the truck again this morning. the SG reports -2.3/-0.8 on factory software and with the smarty it reads .0

Even driving, when let off and coasting down a hill it'll read in the Neg. i just thought it was reading vacuum.

it is odd. but seeing how i'm not going to keep the smarty, i'm really not worried about it. one day i'll get real gauges and know whats reading what.

I do thank you both for the input though.

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