Smarty touch low boost reading?!

[24v Gupp]

I've had the smarty touch for awhile(with boost elbow) and with my 150 injectors I'd see around 36 psi max. I just installed a tst power max 3 today and now the smarty will read to 19.73 but won't go any higher.. I know it's making more than that. Any ideas why it will read to 19 then stop??

[jlbayes]

Because it is reading the boost fooler in the tst......

[24v Gupp]

That was my guess. Do you or does anyone else know how to bypass the boost fooler on the tst and allow that signal to run unclipped to the Econ and allow the smarty to do the boost fooling? If not I'll have to go with an s06 and buy gauges?

[jlbayes]

So you want to disable the feature that is keeping the truck from defueling so your monitor can watch boost? Interesting. And good luck with the s06 on a vp truck.

[24v Gupp]

The smarty keeps it from defueling as well if I'm not mistaken. The s06 would just be there for the timing, I'm aware it isn't the best box for vp trucks to make power(hence the tst). If the only way is to run a separate boost gauge I'm cool with that. Just curious if anyone had found a way around this problem

[J-Pipes]

Originally Posted by 24v Gupp

The smarty keeps it from defueling as well if I'm not mistaken. The s06 would just be there for the timing, I'm aware it isn't the best box for vp trucks to make power(hence the tst). If the only way is to run a separate boost gauge I'm cool with that. Just curious if anyone had found a way around this problem

The S06 comment wasn't necessarily knocking the smarty itself, was more in reference to the fact that the S06 is for common rail trucks, VP trucks use the S03.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[24v Gupp]

Fact. Ha that was my mistake! I meant the s03. Had it on the rain for some reason

[jlbayes]

The tst ONLY fuels off of boost. Disabling it would result in no power.

[24v Gupp]

Would it be possible that the pins for reading boost and fueling accordingly and the actual boost fooling are different in the 9 pin connector? I think I'm just going to get a separate gauge.

[24v Gupp]

Defueling* if so theoretically pop the pin, then the tst still gets the actual boost reading then the smarty to fools the ecm. I could be way off though

[jlbayes]

The tst gets its map signal right from the sensor.

[24v Gupp]

Yes, and then it sends the boost fool after it gets its reading through the original map plug in. The smarty must fool right before the ecm(after the map signal) or it would still read higher than 19. Since the tst gets the original signal if the pin for the fooling were separate and you could cut it, the tst would still get the original boost reading and fuel accordingly and the smarty would boost fool right before the reading got back to the ecm in theory? Trying to put my thoughts in to words. Not sure how it's going though ha!

[jlbayes]

Smarty remaps the ecm. I think I know what you are trying to say but the ecm would get no feedback if you cut the sensor (harness side).

[24v Gupp]

Hm could directly wire it so that it's a straight shot and doesn't pass through the tst and get altered? Side note. Who makes a really good mechanical boost gauge?

[jlbayes]

I considered that as well, no idea how the tst will react or won't. I use autometer. It's a boost gauge, not that critical imo lol

[24v Gupp]

No studs yet:/ and I also don't know how much I'm making with the tst on, the boost elbow I have isn't adjustable. It just has a slot drilled(bd I think). Its plausible I think. It would just depend on what else the fooling is wired to(if anything). May be able to call tst and talk to them about it

[me78569]

Only thing that would be possible is to build a y cable for the map to let the tst read boost and also the OEM harness without the output from the tst being used. I would call that, and ask them if that would result in issues or not.

Jlbayes forgot to add this example to the why stacking is a bad idea thread..... The ECM never sees full boost if you use really any fueling piggyback box.

[24v Gupp]

If you did that wouldn't there be a possibility that either the tst or oem harness would pull priority or something like sometimes the oem would pull the reading and sometimes the tst would pull the reading?

[me78569]

It's an analog signal from the sensor, one device doesn't read as a priority. They both just read the output voltage on the signal wire.

IE: at 0 psi the sensor outputs 4.5v approx
at 5 psi the sesnor will output says 4.2v
10 psi appros 4v

you are thinking that the signal is digital, which it isn't. The ECM reads it as a V output then converts that to a psi scale .

[24v Gupp]

That would work then if it didn't split the voltage. Still going with the easy manual boost gauge route haha.