Originally Posted by AllEuro
I'm confused a few things in this reply. According to the crossfire owners manual that is found in this forum, there is information for both MAP and MAF sensors--I'm assuming no crossfire has both. And based on another reply in this thread, I am guessing the SRT6 has a map sensor and the NA has a maf sensor. What am I missing here?
Secondly, you are a little vague about "no-no" when the NA sees boost. What does that mean? I know there is no actual code in the ECU that literally reads "no-no". My guess is exactly what I stated is the voltage exceeds the parameters set by the ECU-MAF relationship. However, it shouldn't be an absolute. There should be some level of boost (3psi for example) it can read. Unless of course, there are other problems, like the fuel injectors themselves won't be able to handle even small amounts of boost. Or some additional mechanism that Mercedes decided to add to these motors.
There's something I'm not understand with the information found in this thread. Negative or positive manifold pressure technically shouldn't matter (the absolute velocity is the important factor), at least on a MAF-based system.
The MAF along with lots of other systems determines where in the fuel table it needs to be on the NA. It has a MAP sensor and that is part of what measures engine load as it is on the vacuum lines in the front of the engine jsut to the right of the thermostat housing when looking at it from the front.
The SRT does not have a MAF sensor as it uses the MAP exclusivly.
As for the no-no, i'm don't remember what the exact names of the codes are but there are a few and it's along the lines of bad map sensor/incorrect reading for the given parameters or some other tehcnical statement used to encompass that type of error.
As far as boost, if you have the map between the throttle body and whatever you're using for FI, it will always read vacuum.
Hope this clears some stuff up.