I found this going thru some of my old stuff. Its a circuit that uses an LM2917 freqency to voltage converter. I used this for a year or two before I converted over to a PCM that could read the MAF in directly. It works reasonably well for reading in the freqency based MAFs. Basically the circuit works as a charge pump that pumps charge into a capacitor that results in a voltage thats proportional to the frequency. The output is 0-5V for 0-12000 Hz input. The only special concerns with the circuit is that the 1000pf cap. and 55 kohm resistors need to be 5% or tighter tolerance wise. Its also recommended to use a mica capacitor for the 1000pf unit as they have very little variation with temperature. Also, make sure all electrolytic caps used in the circuit are rated for at least 35V, and proper polarity is observed.

You'll need to assemble it yourself, but it shouldnt cost more than $15-20 dollars for the parts.

I also found my old assembled unit if anyone is interested, just shoot me a PM. Its just collecting dust here.

 

Let me make sure I understand this correctly, I make this and have it intercepting the output to the ecu from a lt1/ls1 maf? I assume I'd have to mail order the IC since I live in a smaller town. Is there any calibration in the converter itsself or is that all done through the prom? Thank you.