ok, I need to get mine calibrated and have no idea where to start. I tried the settings that came in the Utec, and I tried the settings that were listed in the manual and neither are close.

Also, when it's reading vacuum in negative psi, is that in/hg? Should it read -15psi at idle when my boost guage reads 15 in/hg?

 

-15 psi is different than 15 in/hg.. I don't recall what my car reads at idle but its different than the gage's in/hg reading.

You have to follow the instructions in the UTEC manual to come up with calibrations.. If your using a GM map sensor, or the TurboXS sensor, then the default settings actually are pretty close. Also the UTEC can read Gage pressure, or Absolute pressure..

 

I have the GM 3 Bar and I've got the suggested numbers that are in the manual for it, but they're way off, it reads at .3 psi at idle. I've also tried the default numbers that were already in there (244/204 IIRC), and those were even worse. I'll read the manual again and see if I can find the steps for calibration.

What's the difference between absolute and guage?

 

Absolute pressure is from a vacuum, therefore at atmospheric pressure its already 1atmosphere (14.7psi) Gage pressure the zero point is already 14.7psi..

Look in your configuration settings and see if your running PSIa or PSIg it should be a clear indicator, if your engine has a very strong idle, it could pull -15psi and using PSIa it could actually read close to zero in absolute pressure.

 

I think I have it set for PSIg.

Would PSIa be different at altitude?

So, would 5 PSIg actually be 19 PSIa? Or is there a conversion involved?

 

Something along those lines, I forgot the exact number but 0psi gage, should be about 14-15psi absolute..

 

Since i'm in Colorado, about 1 mile asl, is PSIa still going to be 14.7, or less than that since the air is less dense here?

 

PSIA is going to be the same, 0psi is still an absolute vacuum, but at that altitude, 0psig is probably around 12-13psi

 

So, I tried to follow the steps to calibrate a MAP sensor straight from the manual (you know, the whole P0, P1, M0 and M1 thing). What I calculated was 10/140 gradient/intercept. This can't be right, can it? Do I have a faulty MAP sensor?

 

you used the numbers out of the utec # 4 ( i think) right?

go into utec and 1-6 are different logging screens. i think you need #4. Took me a hell of a time to get mine right til i discovered the extra logging screens

 

Yeah, I used #4 and the values under MAP, for my m0 and m1 values. I got my p0 and p1 values from my boost gauge.

m0=68
m1-1562
p0=14.7psi (atmospheric pressure, right?)
p1=29.7psi (atmospheric pressure plus 15psi (what my gauge was reading))

Did I calculate things incorrectly?

 

...i honestly don't remember, but your baseline isn't 14.7, it's 0. Try it without the atmosphere addition, and go again

 

This is all documented in the UTEC Docs on their website.. Step by step..

 

I followed the steps in the manual, but apparently I got confused on the atmospheric pressure issue. The manual says to "use your gauge as a reference for pressure. Remember that 0 is atmospheric pressure". So I did my calculations using 14.7 for 0 and 29.7 for 15 psi. I'll try it using without those numbers tonight, but if I remember correctly, I got some really weird readings when I used those numbers.

 

I do not know if any of this is going to help you, but I have a GM 3 bar MAP sensor hooked to my Innovate to log boost and I have it calibrated.

https://www.evolutionm.net/forums/sh...0&postcount=31

Go to this post and in it you will find links that might help you with the calibration.