fuse

I have a lm2 and have it all set up. I just need to know the formula for the map sensor. You know 5volts=11psi 0volts=26 inches type thing. I think its an obdo map sensor.

Tom-Guy

0v = 0 psia, 4.74-4.75v = 9.25 psi. It won't go 5v, but if it did it would read Hyundaidata's erroneous claim of 11.3 psi.

miss-piggy

Joseph, these numbers are not right.

http://wikitest.pgmfi.org/twiki/bin/...rary/MapSensor
http://wikitest.pgmfi.org/twiki/bin/.../OBD1_8bitMBar

Specifically:
mbar=365.9(volts)-29.9

I honestly can't say for certain what your min and max voltage on the sensor is, but you can assume roughly the same as Motorolla sensors which I believe to be .2v and 4.9V. It could be 4.75V as JD has said, but I couldn't say for certain. Honestly, it won't matter. Plug in the equation I gave you and whatever the sensor does, it does.

Tom-Guy

Dunno the minimum voltage, but my max figures are correct.

miss-piggy

The voltages, maybe, the pressures are not as long as we are going based on the shop manual. Your voltage may be correct. Your pressure may be correct, but if we are following the data sheet, both are not correct. I don't believe the Honda sensor to have THAT loose of tolerances to allow such a significant difference in theoretical value to actual value. I've always said I was going to put a sensor on a pressure vessel and compare the different types. I never did. Add it to the list.

fastcrxsi90

are you using an ssi-4 or something similar to get sensor data into logworks? there are plugins you can use for this....especially if obd0...

i will look for the formulas on my pc when i get home...

fuse

The lm2 has 4, 5 volt analog inputs and rpm input. So it record that an afr on the sd card. I know about plugins, ecu control, freelog and what not. I just wanted some thing to record with out all the lap top ---- hooked up. Logworks was the answer in my situation due to I have a lm2 now.

I found this is the service manual. I also recorded my Iat and tp measurements. I am not good at math but I tried doing a slop calculation I don’t know??

Will this help? I will do more math later.

Thanks everyone I will try all the formulas.

Tom-Guy

OK, Motorola sensors are 0-4.9 volt units.

And it looks like the Helms says 0v = 0 psia. As for 9.25 psi at 4.7x peak voltage www.zdyne.com

I think you should stop looking at 8 bit resolution values, that's shoddy and not very accurate. Ask Warner why he was nutshit about 16 bit fuel maps.

fuse

Ok I am using your equation. The only problem is in logworks I can not brake it into 2 things. For instance I can have inhgvac or psi but not both. The table set up will only read to 0 of each so if I am set on inhgvac I can not see boost if I am set on psi I can not see vac. So I need to know something different like 0v=30inhgvac and 2.9v=0inghvac then something like 3.0v=0psi and 4.7v=9.25psi. I am so confused. I can open the same file and set up both and but them up to each other. Then it starts to look like something usable.

Is logworks just gay?

miss-piggy

Joseph, stop. Look at a data sheet before telling me I'm wrong. Then you should look at my SIMPLE ACCURATE calculations and verify that I am indeed correct because on this occassion you are wrong, I can prove it, and it's not worth getting in an argument over. Not to mention I only refer to 8bit calcs when refering to the ECU and my raw formula is totally unrelated to bits, bytes, or anything of the sort. Again, I'm about 99.97% sure I'm right on this one. Take it for what it is worth.

PS: Blake never saw the resolution as an issue with map sensor values so there was never a reason to move from 8bit to 16bit map sensor data allocation thus why he never did it. He was the ultimate proponent of interpolation and not giving a ---- whether the map sensor was 100% accurate. Look back on HT on his ramblings about Neptune and how stupid he thought 24 column fuel maps were.


Fuse, pick a unit and stick with it. -29.92inHG=-14.7psi=0mbar. It's just a pressure conversion. The numbers work. I'm not familar with log works, but pick the unit it works with and give it the defining values it needs.