Question: Why the MDP on an L81 and the MAP on a ZR-1 have the same part number?

[GerryLP]

Hello folks!

I feel like a mouse who just walked-in on a roomful of cats! :L

I was surprised to find out that the Manifold Differential Pressure sensor for the L81 (Part number 16006834) has the same part number (and looks) of a 1990 - 1995 ZR-1 Manifold Absolute Pressure sensor.

I know that what it does is just tell the computer what the pressure is by reporting the difference between 29.92 HG/in of pressure and the lower pressure inside the manifold on the case of an L81. And I believe that the MAP in the ZR-1 functions by telling the computer what the pressure is by adding gage pressure to atmospheric pressure.

So why would both have the same part number? And keep in mind that they both have also very similar dimensions and design. Almost identical. So what gives?

Sorry for disrupting you "Cats"...your humble mouse, otfl

GerryLP:cool

 

[Hib Halverson]

Because they're the same part.

A MAP sensor reads absolute pressure in the intake manifold. It does not measure a differential. It does not measure gage pressure.

The ECM knows BARO because at start-up, right as you turn on the key, it measures atmospheric pressure and the ECM stores that.

 

[GerryLP]

Because they're the same part.

A MAP sensor reads absolute pressure in the intake manifold. It does not measure a differential. It does not measure gage pressure.

The ECM knows BARO because at start-up, right as you turn on the key, it measures atmospheric pressure and the ECM stores that.

Hib,

Does that take place at the same sensor?

I seem to understand that the ECM captures the current athospheric reading and when the difference is generated inside by the engine, the ECM calculates the proper voltage to control the fuel mixture at different power settings.

I am still troubleshooting why the voltage won't change at the sensor when vacuum is applied to the MAP sensor on my Vette.

GerryLP