what is the difference between a map sensor and mass air flow sensor in a 1999 pontiac grand prix?
July 12, 2009 | Car
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Re: “what is the difference between a map sensor and mass air flow sensor in a 1999 pontiac grand prix?”
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Air flow meter is connected to the intake duct. MAP sensor is on the back of the upper intake with a green 3 prong plug and has a single vacuum hose going to it.
whats the difference?…about a hundred and fifty buckaroos,but……the mass air flow will be on the air intake tube leading up to the throttle body……it will have a screen in it with some wires with resistors on them….your map senor will be on the manifold and will more than likely have a vacuum hose or it will be mounted direct into vacuum source,,….mass air flow sensors have a high failure rate and are a regularly replaced item
The Mass Air Flow sensor is usually right on the airbox itself, with a 4-6 wire plug (where the air filter is, and on most GMs, is tucked in a corner of the engine compartment), the MAP(Manifold Absolute Pressure ) sensor tells the actual pressure/ volume of air entering the engine, and is usually mounted on the firewall, or the rear of the engine, with a 3 wire plug, and a single vacuum hose leading to it. Very few vehicles have both. If you’re experiencing a no start, or start/ stall condition, I’d point towards a MAF problem. The reasoning is simple..; it’s the MAF’s job to measure how much air is coming into the engine, it’s temperature
( and therefore it’s oxygen density), which allows the ECM to determine how much fuel it needs to inject for a proper A/F ratio. If the ECM sees no air coming into the engine.. it allows no fuel to be injected, and the engine will die within seconds of being started
the map sensor is on the throttle body and the mass air flow sensor is down closer towards your intake filter you are proble unpluging your map sensor possible your tps sensor ( throttle position sensor) i say this because if you unplug you map sensor your car will not run at all wont start and if it is started and you unplug your map sensor it will die
Most cars seem to have one or the other. The MAP is a Manifold Air Pressure sensor…and is probably close to your intake manifold [on the top of your motor]. The MAF sensor is usually in your intake tube or in your airbox after the airfilter.
Just by chance, does the thing you unplugged have oil on/in it? If so, it may be that you need a PCV valve…a part of your EGR system that regularly needs replaced and is much cheaper than either the MAF or MAP sensors.
Whenever these fail, your check engine light usually comes on…if so, AutoZone still offers free trouble code readings and other help.
Good luck!
The mass air flow sensor is located right after the air cleaner box on the air duct.