I have a question about MAF sensors. I know that they measure the quantity of incoming air but does it measure actual oxygen content within the air. For example, everybody knows that air in the atmosphere is 19% oxygen, 80%nitrogen and 1% other gases. But nitrous oxide has more oxygen content per the same amount of airflow. Can the MAF sensor reconize this extra oxygen or is it just calibrated for atmospheric air? Just curious. Any help would be great.
They measure the "mass" or density of the air. They basically generate a frequency based signal based on a hot wire.
You could run carbon dioxide or argon over it and get readings... it doesn't have any idea of what the chemical composition of the gas is.
The MAF also measures the air long before it enters the engine. Nitrous is injected closer to the engine and after the MAF, so the computer never sees any of it. I've never used it, but carbs work the same way too. Nitrous after the incoming air. That is one of the reasons that you have to also inject more fuel, since the computer has no way of knowing that there is extra air coming in.
Brian
Okay, here is my problem and question. I have a 87 GN with stock turbo,30# injectors,307 fuel pump,AFPR,Hooker cat back exhaust. When I have the stock chip in or the Thrasher chip for stock injectors, the engine is lean at idle and it will ping some at wot. I have a VDO boost gauge and the boost only is getting up around 14psi where it should be. The engine idles rough and I have checked for vaccume leaks and the fuel pressure doesn't seem to affect it none if set anywhere between 40 and 46 psi with vac. line off. I did notice when I unplug the MAF, it will idle smoother. My scan tool is showing the MAF at idle around 006. Does anyone think that my MAF is actually bad or going bad? And if so, would this also cause some wot ping sometimes? I tried tapping on it to see if that would do anything, but it didn't. The o2 is switching lean to rich normally between 600 and 800 and then jumps down in the 200 range for some time then goes back up. I have the tps set at .42 and the IAC is around 20. I can spray a mist of Carb. cleaner into a vaccume line and it will smooth out. Thanks for any help,Tom.
What are the blms at idle?