I need a map sensor... not for MS...

[740ATL]

I finally got my Tech Edge 2A0 working (spells, prayers and divinations) and I have been datalogging on my 740 LH2.2 to try to find out what the F is wrong with it.

Well, now I'm just plain hooked. I've got AMM load (the red-blue wire), Narrow Band O2 voltage, RPM, in addition to AFR, and I have one more aux input... so I figure a MAP sensor would put the icing on the cake.

Lots of cars have MAP sensors... there's even the Megasquirt MAP sensor... any in particular you'd choose? I need something with a 0-5v output and can be easily configured (ie powered up).

here's an example of the coolness... there is no limit to my geekness...

this is a 2nd gear pull followed by a quick 3rd gear pull (rpm is exactly 1/2 of actual)
http://i.pbase.com/g4/75/540175/3/59978716.morning6.jpg

here's me just stepping on and off the brake pedal (stopped of course, at idle)
http://i.pbase.com/g4/75/540175/3/59995610.mondayPM_2.jpg

and there's a LOT more... http://www.pbase.com/740atl/datalogging this is so cool... and useful...

Mike

[ovlov760]

Could you use the same GM map sensor that megasquirt uses?

[740ATL]

yeah, don't see why not... GM sensor it is.

I was just wondering whether there were others out there that were more up to the task.... I have a junkyard full of cars available to pick from... I suppose I can grab several.

thanks.

Mike

[Matt Dupuis]

Could you use the same GM map sensor that megasquirt uses?

Megasquirt doesn't use a GM sensor.

[JohnLane]

Many aaftermarket systems use the GM sensor so that it will always be an easy off the shelf item to replace. They can be had in whatever number of bars of sensing range you wish for.
They all require a 5 volt reference signal.
My Electromotive uses GM sensors.

[ovlov760]

Megasquirt doesn't use a GM sensor.
Maybe i'm thinking of the 3 bar GM sensor some people use with it.

[the poi]

well apparently the gm sensor is a motorola mpx series, just liek the one MS uses. so i guess its the other way around.

[ovlov760]

well apparently the gm sensor is a motorola mpx series, just liek the one MS uses. so i guess its the other way around.
Is it cheaper to get it from Motorola or GM?

[swedefiend]

Is it cheaper to get it from Motorola or GM?

The MPX sensor needs a voltage conditioning circuit. Maybe a few other little items. I wouldn't know because I have never pried into a GM Map sensor (or studied at length the circuit supporting the MS sensor).

While it may be true that GM uses the Motorola sensor (I cannot swear to this), the GM sensor would be the solution for someone not wanting to have to build a board to support the MPX sensor.

I mean when you say cheaper, the answer would be: the MPX is cheaper. That is, until you try to stick it somewhere under the hood and have to build the board and buy a case and ...

Then the GM sensor would probably be cheaper :e-shrug:

[740ATL]

dude. Thanks for the info! I am heading to PAP tomorrow AM. I realized today I would need to also fab something to deliver a 5Vref to use the MXP sensor.

As naive as it sounds, I want something I can feed a 12v+ to and ground, a vacuum line, and spit out a 0-5v signal for the tech edge box...

Price isn't really a problem as I can get these things at the JY for next to nothing... just have to tell the lady it's a cruise control computer or something.

any idea where they're found on GM vehicles?

many thanks.

Mike

[swedefiend]

any idea where they're found on GM vehicles?

I don't really know.

I like to get stuff like this off of a car that was previously turbocharged.

So, I would be looking for a GN (unlikely, eh?) or a Turbo Probe (which is where I found my sensor - on the middle of the firewall).

They are all pretty much shaped the same way, so that is how I look for them, then when you see the vacuum line going to them, you know that is what you want.

Happy hunting!

[740ATL]

Hey guys, I decided I'm just going to get a GM 3bar map sensor... they're pretty reasonably priced.... however, I'll need a 5 volt reference signal to it.

I found this little circuit to generate the 5 volt reference signal... http://www.play-hookey.com/analog/experiments/plus_5_volt_ps.html

whaddya think?

Mike