3" GM MAF Signal

[wallyman]

I was wondering if anybody knows the what frequency ranges a 3" gm maf sends out and what frequencies the 1g mas sends out. I plan on building my own translator. Please if you have no idea then dont answer this thread. This could be critical to my ECU.

 

[huafist]

I was wondering if anybody knows the what frequency ranges a 3" gm maf sends out and what frequencies the 1g mas sends out. I plan on building my own translator. Please if you have no idea then dont answer this thread. This could be critical to my ECU.

I think you're going to find that by the time you do the R&D to build a translator, you'd have been better off buying one. You're gonna have to be pretty proficient in integrated systems programming as well, because not only does the MAF-T translate the signal from the GM MAF to the Karman values that the DSM ECU expects, it's also designed to alter said Karman values to compensate for different injector sizes. If memory serves, the code on the EPROM is encrypted as well. I'm not sure what CPLD/CPU the MAF-T uses (will check tomorrow), but yeah, it's gonna be a hell of a lot of work.

 

[tstkl]

a few things, i cant really help you with your problem, but i have some suggestions....

1, this would be better off somewhere else if your looking for inteligent posts, maybe try asking the the tech discussion section or something...

2, i think it should be fairly simple since your not going to have anything to change those values, you just want to have a direct translator, so good luck...

3, have you thought of getting an older version of a maft used, if your souly worried about prices, and you dont want the translators tuning appilities, you could get one of the older versions....

 

[wallyman]

I did some google searching and quick looking around fro about 20 minutes and still couldn't find any answers to my question with all the specifics I was wondering about. This is what it seems like so far (let me know if I have misunderstood anything thus far):

The DSM MAS: sends out 3 signals, one is a fequency signal that is a pulse at an unknown peak value ( it does not sound like it is a sinusoid or anything else), the second and third are 0-5v signals. The frequency signal is all that matters since it is the majority of what determines air flow. The other two are pressure and temperature of the air. The ECU looks at all 3 and detrimes the actual volume of air flowing.

The GM MAF: sends out 1 signal, 0-5 pulse at varying frequency which is a solve all impying air pressure and temp based upon the the frequency sent out. Its range is much higher than the DSM, but that is not important to me yet. The ECU's on GM's are setup to interpret its values knowing that it has already infer's temperature and the MAP handles the pressure.

So, it sounds like the DSM MAS translator is frequency divider with set values for the pressure and temperature (which can be adjusted via potentiometers inside of the unit). I am not sure about this however. To answer my question I would need to see the output values of the frequency based signals VS flow (or RPM). A voltage divider is as easy as http://www.national.com/ds/LM/LM555.pdf reference page 8. If the output values are not so linear versus flow.

I guess what I was asking was really this: does anyone know the output of frequency VS flow for the DSM MAS and the GM MAF used with the translator? Also, did I make the right assumptions about the GM and DSM sensors?