Has any body successfully connected a MAP, sensor to the innovate motor sports Lm-1 RPM converter, Aux inputs? I trying to figure out how to get a base voltage for the MAP sensor @ a given psi, to configure the LM-1 aux program. I would like to monitor, rpm, boost, vacuum, and throttle position along with my afr. I’m thinking I may have to simulate a known pressure at the MAP sensor to record the high and low voltage readings within my anticipated operational envelop. Also if anybody has done this on a car without an ECU how did you get the sensor impute to 5.0 volts, and the output readings no higher than the 5 volts that the Lm-1 can handle?

I’m also going to incorporate a late model GM TPS, on to one of my carburetors, if any body knows where I can get the weather tight connector found on the harness of say... a 95 Camaro that would be very cool also.


Thanks

Tom

Tom,

if you are using a 2 Bar Map sensor, then you are going from about 30 in-hg to 14.7 psi (or 29.4 psi for a 3 bar sensor), over the 5 volt spread. you could turn it on & crank up the presure with a gauge on it & see how high the LM1 reads. Im sorry but I have not tried to hook it up, or anything so I dont know where to start. You might have to add some kind of resistors to limit the voltage to the LM1 so that you dont exceed thier 5 Volt rail.

it should be rather simple to figure out where ambient pressure is, just hook it up & not apply vacuume or pressure & see where it reads.

Have you tried to ask innovate if they have a recommended circuit? they are fixin to release thier "Aux Box" I would imagine that they already have a circuit designed & might help you out. they have been pretty good about communication when I bought mine.


for the weather pack connector, I would goto the wrecker & just cut one off of a car. I have done this quite a few times with good success.

Bob

A MAP sensor simply outputs a liner 5v reference voltage. Just make sure your input voltage is 5v and you have nothing to worry about on the output side.
Just to make sure there is no confusion: There are two types of pressure readings; Absolute and Gauge. Gauge references the surrounding atmospheric pressure (approx. 14.7psi or 1-bar or 1-atm or 100kPa …all the same) and absolute references a perfect vacuum. So 1psi gauge is 15.7psi absolute.
Manifold Absolute Pressure (MAP) is pretty self-explanatory as to what it referances.

I think GM sensors outputs 0-5v.
So a 1-bar GM sensor is going to give you 0v at absolute zero pressure (or -30in hg gauge) and 5v at standard atmospheric (1-bar absoulute or 0 gauge).
A 2-bar GM sensor is going to have the same lower limit, but standard atmospheric pressure will read around 2.5v and at 2-bar (14.7psi gauge) will read 5v.
And on with the 3-bar (29.4psi gauge).
You can interpolate the values in between.
You can test this out with a power supply, voltmeter, and mighty vac (optional). Ground terminal A, supply terminal C with 5v. Connect the volt meter to B. Don't fret if your readings are off alittle in free air because it will vary with altitude and weather.
Connect the mighty vac and pressurize or apply vacuum the sensor. Pay attention to the gauge and output voltage. This really isn't necessary because the sensor is linear.
Other sensors outputs are different. AEM (and others) output range is 0.5-4.5v and Ford uses frequency output.

Great, how do I get a 5v source? The LM-1 aux input box runs off 5v. There is no terminal, so you'll have to open it up and splice into it. Innovate can tell you where to pick it up. Also, you could make your own voltage converter. It's not hard, but I'm no sparky so I can't help you there. Lastly, you could try to find a voltage converter for portable CD players, cell phones, etc. but they usually run off less then 5v.

If all you wanted to do was monitor a MAP or TPS, you don’t need the aux input device. They give you the pinout of the DIN connector so you can pick up the +5v supply and inputs right from the LM-1. The catch is you need the aux input box for RPM, thermocouple, etc.

You can config the software to read raw voltage and convert it yourself. Or, you can tell the software what kind of sensor you have and it will read in kPa.

Hope that helps. I haven’t played with the LM-1 software or inputs much. I have a stand alone computer in my car and use it for all data logging/tuning.