mass airflow sensor$
- Thread starter rjsrt10
- Start date
AZTVR
Enthusiast
$250-ish....
345s-bspinnin
Enthusiast
Since when do Vipers have mass air flow sensors?
AZTVR
Enthusiast
Like you, that was my first reaction, also. I did a search though, just to learn a little more. http://forums.viperclub.org/threads/641567-Does-anybody-know?p=2912478&viewfull=1#post2912478
Allan
Enthusiast
Vipers are like the rest of Chrysler's vehicles and use what we call a 'speed/density' method for fuel calculation. (crankshaft RPM and manifold air pressure 'vaccuum') Most other manufacturers use a 'mass air-flow' method for fuel calculation. A Viper don't gots a mass air-flow sensor on it..............I think you're looking for oxygen sensors, Vipers have 4 of those in two 'pairs'. 2 pre-cat, and 2 post-cat. The pre-cat are for fine tuning fuel trim, the post-cat are for catalyst monitor only (do not affect driveability).
AZTVR
Enthusiast
As JonB says, "The year matters."
The part # of the thing that Dodge calls "Sensor, mass airflow" for the Gen 4 is 05037945AA .
I am curious to know why someone would need them for a Gen 4 already?
The part # of the thing that Dodge calls "Sensor, mass airflow" for the Gen 4 is 05037945AA .
I am curious to know why someone would need them for a Gen 4 already?
AZTVR
Enthusiast
And a little Google search revealed that Paul Scharf is selling a pair of used ones on the 'bay right now, so, that would indicate why the interest in what a pair of new ones cost. I'd say that his asking price is pretty much in line with what one would expect for used parts. He is a respected site sponsor vendor.
I have the K&N intake kit. Great for winter months with no rain, but summer....well not so much fun to not be able to drive in the rain with this intake installed. K&N requires you to use a new stick on seal. So to switch back to factory air box for summer would require removing the stick on gaskets and replacing them with the factory rubber gaskets. If I had a second set it would be more easy to make the swap.
Allan
Enthusiast
Wow, did they go to a MAF system on the genIV ? ....I wasn't aware of that.
AZTVR
Enthusiast
Good idea !
Gen-4 is a combined MAF/MAP system. It uses both systems.
Steve M
Enthusiast
My guess would be for emissions - if you can more accurately measure the airflow in, you can more precisely add the fuel you need to get the proper emissions going out. Speed density requires a lot of data to cover all possible operating conditions...a MAF can pick up those differences a little more easily, and speed density can fill in the areas where MAFs are bad (throttle transients).
Allan
Enthusiast
I wonder if they're design is like GM's. ( they have been using both for quite a while now ) GM runs the MAF system for primary fuel / timing contol. the MAP sensor is primarily for EGR monitor self diagnostics. PCM looks for MAP change when it opens the EGR valve, if it doesn't see a pressure change when the valve is opened, it sets a code for insufficient EGR flow. MAP sensor is also a back-up for MAF sensor in the event of failure. Late GM PCMs are very smart and also use a 'rationality strategy' of monitoring TPS, MAF, MAP, to make sure that all the inputs are plausable -what is expected for the particular driving condition. If something is askew, the PCM can figure it out easier. The Viper motor does not use an EGR valve, so I wonder what their deal is.
Allan
Enthusiast
I wonder if they are using both to really keep tabs on whats going on with the variable valve timing. (monitoring engine vacuum so the pcm can better track the effect of cam timing and engine load) If they are using MAFs on the car, that would be the primary input for fuel/timing control. MAP would be secondary / back-up / or diagnostic input only. Also PCM will use the MAP input KOEO (during ignition key sweep to start) for barometric pressure reading to establish baseline for fuel control. (they've always done that)
Allan
Enthusiast
Chrysler has always been very proud of how killer their speed density systems are. really really fast thinking computers to make all the correct fuel calculations with just tps, map, ckp, cmp, cts, iat. They do alot better than GMs speed density systems. I have alot more experience fixing the GM crap because they just couldn't figure it out like Chrysler did, hence more problems.
Allan
Enthusiast
Ford used to be predominately MAP (speed density systems as well) -called it a B/MAP sensor. Barometric/manifold absolute pressure sensor. Like Chrysler, used the same sensor for the baro reading during KOEO condition while the key is being turned before the motor starts to crank. When Ford went to MAF systems, they figured out a way to calculate baro by 'look up tables' in the pcm for 'designed volumetric efficiency' of the engine its controlling. So the baro on a Ford is an inferred value by the PCM. -Fords don't have both sensors.
