Hello all! Not quite a newbie to the forum, but I am getting back into the Thirdgen scene.

I've been searching for a couple hours now and cant seem to find a real dedicated thread or explanation on the differences between the different MAF sensors. I seem to remember reading a thread a few years ago about the MAF being limited in it's resolution due to the ECM being an 8 bit system and that is why it cannot read a value higher than 255? I have even been spending sometime on Alldata trying to get an idea on how the signal is interpreted. I guess I am trying to learn the differences between the different MAFs. One thing I can find absolutely no information on is the MAF for the Turbo 3.8s, let alone how different THOSE sensors work and read. If there is a sticky and a good thread that I have missed, please direct me to that. I cannot find ANYTHING.

 

Search Vader’s threads. He has more than 1 on tpi maf.

 

I was browsing his a posts a little bit. I may buy a book to try and get this figured out. I'm looking for more than interchange information. I'm looking for differences in the actual signals and ranges of each sensor.

 

To what end? What do you hope to accomplish?

 

The range is to 255gps on tpi maf. If your wanting more information you might want to contact blower works.
http://www.blowerworks.net

 

I'm just trying to get a better idea of how it works. My main question is the difference better a TPI MAF and a Turbo MAF. Like, is the turbo MAF as limited as the normal TPI MAF sensors in terms of how much flow it can measure? And how different the signals are.

 

I may have just answered my own question. Looking at one of my old text books. "Many General Motors PFI systems either use or have used a MAF sensor. In the mid-1980s, two different MAF sensors were used; one on Buick engines and one on Chevrolet engines. Buick engines used a MAF manufactured by AC, a division of General Motors. Chevrolet engines used a Bosch unit. In the late 1980s, the AC unit was discontinued and a unit built by Hitachi of Japan was used on Buick engines. Chevrolet engines were by then no longer equipped with a MAF sensor, but used a MAP sensor instead."

I've read plenty about how the TPI motors went back to speed density but never really read to a reason as to why.

 

It continues to explain the difference between the two styles. "The AC MAF sensor contains a screen to break up the air flow. After the air passes through the screen, it flows over an air temperature sensing resistor. A sample tube then directs some of the air to flow over a heated foil sensing element. The power to heat the sensing element comes from a fuse or relay, depending on the application. The circuitry of the MAF sensor controls current flow through the foil sensing element, maintaining it at 167 *F above the incoming air temperature, as measured by the temperature-sensing resistor. The power required to keep the sensing foil element 167 *F above incoming air temperature is a measure of MAF. This value is sent to the PCM as a digital signal ranging in frequency from 30 HZ to 150 HZ. The PCM compares the MAF sensor information to a preprogrammed look-up chart and finds air flow in grams per second. Using this value along with engine temperature and engine RPM, the PCM can calculate exactly how much fuel is required to achieve the desired air/fuel ratio. Mass air flow readings are taken and air/furl mixture calculations are revised about 160 times per second. Use a Hertz meter to measure the sensor's output; the frequency will follow the rate of air flow."

"The Bosch MAF sensor works much the same way as the AC unit except that a hot-air element is used instead of a foil sensing element. It is also an analog sensors the voltage signal will simply follow the rate of air flow and can be measured with a volt meter. Also, each time the ignition is turned off after the system has been in closed loop, a separate burn off module momentarily puts enough current through the wire heat element to make it red hot. This burns off any residual accumulation, keeping the sensor accurate. It is critical that the sensor wire's surface be clean because any accumulation of deposits retards its ability to transfer heat."

So evidently the Turbo models used a digital signal over the TPI's analog signal. What I can't seem to find is if the Turbo MAF can read a higher air flow value over the TPI MAF. THAT is what I'm looking for input on.

 

Good luck. The info is probably out there, but the solution is probably less attractive than simply running speed density.

Aside from other benefits, the MAP sensor is a lot less expensive. They hardly ever fail. It simplifies things under the hood, reducing air intake complexity, and eliminates an entire set of clamps/hardware and places the intake can leak. From personal experience a SD system will still run pretty decent with all kinds of vacuum leaks and messed up fuel pressure, while a solid running MAF thirdgen is rather unusual.

 

Oh for sure. I'm not trying to beat a dead horse there, I know SD is a lot more reliable on these systems. I just was having a hard time finding some solid technical data on the sensors. SD is a pretty straight forward system. I'm looking to either piggy back the GM EFI system or do a stand alone system for a boosted build. BUT that's for a whole different can of worms, let alone, a different thread