Wiring map sensor into external output

[badls1]

I was wondering if I can wire a 2 bar map sensor into my v1 as an external input. How would I do this. I'm trying to log pre intercooler boost pressure with another map sensor.
Thanks, curt

[joecar]

Yes, thru one of the 0-5V analog inputs... and then we can create a calc pid for it (so it shows in psi and kPa).

[ferocity02]

Where would you get 5V reference for this? Can you tap into another 5V source or is that a no-no?

[badls1]

Yes, thru one of the 0-5V analog inputs... and then we can create a calc pid for it (so it shows in psi and kPa).

Okay sounds good. I'm actually going to need to go 3 bar since it will probably be more than 15 psi. Will one like this do the trick?
http://item.mobileweb.ebay.com/viewitem?itemId=121041299443&index=0&nav=WATCHING&nid=67050350433

[joecar]

Where would you get 5V reference for this? Can you tap into another 5V source or is that a no-no?You can borrow an existing 5V reference... and then measure the voltage of the 5V reference to see if you've created a problem by borrowing it.

[badls1]

okay I ordered a 3 bar map sensor. can wire this directly into the pcm somehow or will I be better off using one of the ext. inputs on my v1?

[ferocity02]

You could wire it into the EGR wiring sensor wiring. That's what I did for my fuel pressure sensor.

[joecar]

You could wire it into the EGR wiring sensor wiring. That's what I did for my fuel pressure sensor.That would work.

[badls1]

my car doesn't have any egr wiring. can I hook it up through the a/c press. sensor?

[badls1]

got it wired in. how do I go about making my pid for it?

[ferocity02]

Did you wire it to the a/c pressure sensor or straight to the external input.

[joecar]

Where is it wired to...?

What kPa range does 0-5V represent (is it 0-200kPa)...?

[badls1]

I used the a/c 5v refrence and the a/c signal. I then made a pid that displays the a/c signal. it changes when I put pressure on it but its not right. Its a 3 bar map sensor

[joecar]

Can you confirm that the 3-bar sensor maps 0-300kPa to 0-5V...

is this is the case then your calc pid would multiply the AC pressure voltage pid by 60 to get kPa

( can you measure it as you apply vacuum and pressure to it...?)

(remembering that going under 100kP is vacuum, and going above 100kP is pressure).

[badls1]

I just emailed the seller about it. I would assume that it does. So I just changed my pid to multiple the AC pressure by 60. when I turn the car on it should read around 100 kpa and if I put 10 psi to it, it should be around 170 correct?

[badls1]

at 0 it reads 94.1kpa, at 13.5~180, 16.5~202, 17.5~212. This is testing vs my mechanical boost gauge. so it seems to just be off by ~7 kpa the whole time.

[joecar]

If you can get a few V:kPa pairs of values, we can write a calc pid fir it.