scan gauge 2, smarty, boost readings.

[Killer223]

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.?

[Mopar1973Man]

Smarty tends to modify the data for some reason. I've worked with Pepsi71ocean with ScanGauge II and Smarty issues but it seems the Smarty tends to modify the data coming out so other device tend to display erred information.

[AH64ID]

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.

[Mopar1973Man]

Something is going on if running a program is skewing the output data versus stock programming and shows correct.

[AH64ID]

Yeah, but it's going the wrong way from what would be expected if it was skewing.

 

I am thinking its just a random coincidence.

[Mopar1973Man]

The I would suggest to the OP to re-run the settings again and see if the same thing is happening twice?

 

So AH64ID if he can reproduce the problem it would be a software error on Smarty part correct?

[AH64ID]

Possibly, but the appearance of the error is on stock software not Smarty software...

[Mopar1973Man]

At any rate the OP should be able to get a new flash for his Smarty to correct the ECM software? Most likely from Bob Wagner correct?

[AH64ID]

Depends.. If he has the latest software then that's all there is.

Like I said this is something I have never noticed, and I pay a bit of attention to my gauges and OBDII readouts.

[Killer223]

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.

[AH64ID]

Very interesting.

Look at the individual gauges on the SG and see what one changes.

MAP absoloute, and ambient absoloute.

[Mopar1973Man]

From what I understand the Smarty updates to the most current stock flash so I wonder if the Smarty tune itself was the change in all the MAP readings? Still I would just for fun contact Bob Wagner and see what he's got to say or if there is actually a software bug.

[AH64ID]

Yes the Smarty uses the latest software at time of writing, but it should also leave the same software on the truck when it goes back to stock.

It's interesting for sure, especially with the error in OEM software.