Online MAF Analyzer

For best results

1. Use a graphing scan tool
2. Use manual PID selection to deselect all parameters except RPM and MAF gm/sec.
3. Make sure the engine is at operating temperature

   By deselecting all other parameters, the scan tool will update faster and give more accurate results.

1. The calculator is only accurate at wide open throttle.

   (ZERO intake manifold vacuum)

2. Drive with wide open throttle through first gear until the transmission shifts

   (Near redline for manual transmissions)

   The analyzer is more accurate at higher RPMs
   (over 4000).

3. Use 'freeze frame' or a 'movie recording' feature to collect the data if a graphing scan tool is not available.

For best results

1. Only input your altitude OR Barometric pressure, NOT BOTH.
2. Most vehicles will have about 75% to 85% volumetric efficiency.(except Turbo/Super Charged)

   The analyzer assumes that 82% is correct. If you know an engines true volumetric efficiency, you can override the default 82% in the advanced inputs section.

3. Don’t mistake true barometric pressure with the calculated barometric pressure reported by most weather and news stations.

   In almost all cases, altitude should be sufficient, just leave baro blank unless you are certain of your true barometric pressure.

4. You can find detailed elevation info here:

   geonames.usgs.gov
   At this site enter State, County and City
   Enter the City name where it says 'Feature'
   This is a little confusing but we didn't build this site, we only reference it;
   Or type something like "elevation of Atlanta Ga" into your favorite search engine

This analyzer is actually measuring the volumetric efficiency (VE) of the engine based on input from the MAF sensor. A low VE calculation means one of two things. Either the engine is pulling in less air than it should, or the MAF sensor is under-reporting the amount of air entering the engine. If the MAF sensor is not reporting correctly, then fuel trims will likely be very high, indicating a lean condition. An engine breathing problem that is causing too little air to be drawn in could be caused by plugged exhaust, restricted intake, incorrect valve timing or other mechanical fault. When a breathing problem exists, fuel trims are often fairly normal or maybe slightly negative.

Since every engine has a different volumetric efficiency, normal for one engine may be low for another engine. Don't assume that an engine that calculates to 76% VE has a problem, that may be normal for that engine. The MAF analyzer is a "close enough" tool, it is not meant to be perfect.

Typically, when a MAF sensor or other VE problem is bad enough to cause an issue, it will be very obvious when using the MAF analyzer with VE calculations below 70%. If analyzer shows the results in a yellow box, there MIGHT be a problem, but not necessarily. If the results are in a red box, there probably is a problem with MAF sensor calculations or an actual engine breathing problem such as plugged exhaust or incorrect valve timing.

MAF Analyzer Download