Hi,
I'm looking to change my MAP sensor and I've already placed my order at rockauto.com
The thing is under MAP they have absolute and differential sensors and I ordered a differential sensor. The more I read and look into it the more confused I get. What is the difference and which one do I need? I'm afraid I've ordered the wrong one and I need quick help, so I can change the order before they ship it.

The car is a 1987 Camaro 305 4bbl (H)

Thanks in advance.

 

I'm confused as to why you need a MAP sensor on a carbureted engine? Maybe you mistook the circle air cleaner to be concealing a carb instead of tbi. '87+up have EFI engines only unless you swapped out.

 

There is a MAP and a BARO sensor on the LG4 engine in 1987

 

That hurts my brain. I looked it up and you're completely right about the 2 sensors. Only the "MAP" reacts to vaccum the opposite way EFI cars do, making it a differential pressure sensor instead of an absolute. They're chillin on either sides of the brake booster in the engine bay. I apologize for my starkness, mine are disconnected, out of sight and out of mind; explains a lot.

 

Closer to the fender is the MAP and closer to the engine is the BARO? The BARO is supposed to be disconnected. Does it have seafoam glued to the inlet?

I've been searching for several days now and all I get is controversial information from the internet.

I've decided to stick to STM brand to ease my search. For my car they have two MAP/BARO sensors-the AS6 and the AS10. Even their official online catalogue is confusing me and I don't know with 100% certainty which one is the actual MAP sensor I need.
As far as I've deduced from the million different listings I've seen I think the AS6 is the BARO and the AS10 is the MAP. However when I search it by car and year I get AS6 as the MAP...

If someone actually knows, please explain which engines have which of these:

Manifold Absolute Pressure
Manifold Differential Pressure
Baro sensor

 

Carb engiens use a VAC sensor (vacuum from the maifold) and an BARO sensor (open to the air- no hose attached). Speed/density EFI stuff uses a MAP sensor.

I'm guessing that the Pressure Differential Sensor you are referring to is the VAC sensor. They read effectively the reverse of a MAP sensor (i.e. they are not the same as a later model MAP sensor).

 

I think we solved the mystery.

Carb engines--->(VAC = Manifold Differential Pressure sensor) + Baro sensor
EFI---> MAP sensor = Manifold Absolute Pressure sensor