If I run full time open loop, can I ditch the MAF? Is it still needed for anything?

 

It is needed for your car to run...

Running full time open loop allows you to ditch your narrowband o2 sensor. Your maf is still necessary in order to determine how much air is entering your engine.

It would be easier to go the other way (but still not really possible) by forcing closed loop if you had a really really fast acting o2 sensor and system for compensation you might be able to manage going without a maf.

Speed density is an air metering system that is available though, look for the speed density discussions in this forum to understand that system a little better, it ditches the maf entirely by adding manifold absolute pressure and temperature sensors. It requires a fairly complete knowledge of basic engine function as well as a lot of reading to understand all of what is going on though.

 

OK, that makes sense. I read up a bit on speed density a while back, but I run the 96530006 rom and it wasn't/isn't available for it. I have the JDM MAP sensor, so I'd just need the GM IAT, but I don't want to try that route until I have a better tune on the car.

Wouldn't I still need the narrowband o2 sensors to see what my STFT and LTFTs are, though?

 

You still would need the maf for the timing map. Plus, even in closed loop the ECU needs some idea of how much fuel to inject.

 

I was sure I was missing something (probably many more things) I wasn't considering the system seriously anyway. If you wanted you could try matching timing on a map with injector pulse width and rpm as axes but of course it is kind of a silly system even hypothetically.

 

Fuel trims are based on closed loop so if you're running full time open loop you won't use trims. You just adjust your map to get your desired afr.

 

so then if your adjusting it by yourself.. why would you need a MAF? you wouldnt?

 

the ecu still needs to know where to look in the maps to get the timing/fuel values. It gets that data from the maf or map/iat (sd).

The only way to ditch the maf is to convert to speed density or a MAFt blow through setup. FYI...SD is out for the 0006 rom now.

 

ooooooh ok that makes it pretty clear
thanks!!