MAP Sensor Help

[Kies277]

I have a 2017 BMW 320i and it is throwing a code. ISTA says that the car is not seeing the expected pressure increase in the intake manifold when the fuel ventilation valve opens. The valve is new and working.
I was checking the MAP sensor with data logging and the MAP sensor is showing 13.6 psi at idle (like .093 bar). During driving, with some WOT, the sensor only increases to about 14.3 psi or so. While idling and revving the engine, it barely hits 14 psi.
Shouldn't I be seeing more fluctuation in the MAP sensor than 1 psi? I don't know a whole lot about MAP sensor operation.

[328 Power 04]

What are all the codes exactly?

Along with the environmental data that comes with the codes

[Kies277]

The code is 190F08
Ambient 25c, Engine 107c, Terminal R, 85.3 km/h, 1423.5 U/min engine speed.

[328 Power 04]

It's really hard to be helpful if we have to drag detailed answers out.

[Kies277]

It's really hard to be helpful if we have to drag detailed answers out.

It is not a detailed question. I am only asking if, in general, should there be more fluctuation in a MAP sensor reading. I wasn't asking for diagnosis of the codes or anything, I was only looking for general MAP sensor info.

[Kies277]

Does anyone have the DME Pinout for the A46*2B 58-pin connector? It is on a 2017 320i F30 with an N20 engine. I am specifically looking for the differential pressure sensor pins. It appears that the sensor harness was replaced and I wanted to check that they were put back correctly. Right now the three wires are on pins 18, 36, and 52. I am getting a 195014 code and am trying to diagnose it. The vent valve and pressure sensor are newly replaced.

[bmwdirtracer]

It is not a detailed question. I am only asking if, in general, should there be more fluctuation in a MAP sensor reading.


In that case:

YES.

:eatpop:

[MauiM3Mania]

Threads merged.

[Kies277]

Thank you, that's exactly what I needed. 😀




In that case:

YES.

:eatpop:

- - - Updated - - -

Awesome, thank you.



Pin 52 is a yellow wire going to pin1 of the venturi nozzle pressure sensor. Pin 36 is sensor ground, going to pin 2 of the venture nozzle sensor. Pin 18 is sensor supply, a white wire going to pin 3 of the sensor.

[bmwdirtracer]

By the way, your original post said "expected pressure increase in the intake manifold", but the sensor you're referring to now isn't measuring pressure in the intake manifold; it's measuring pressure at the venturi nozzle. A MAP sensor in the manifold would certainly show a greater change than 0.4...but not necessarily so, for the venturi nozzle. Are you watching data for the venturi nozzle sensor, or the manifold, or the intake pipe? 3 different sensors, the three will show three different pressure readings. That's why Abel was asking for specifics....

[Kies277]

I thought I was watching the Venturi nozzle pressure, but it turned out to be the charge pipe MAP sensor. I found the current reading for the Venturi sensor though.

In this post, I wasn't looking to diagnose an issue, I was looking for general information on how the MAP sensor is supposed to work since I have never really messed with them before.

I appreciate the help and info from everyone though. I am working the issue with my car but I don't want to just fix it. I want to fully understand the whole fuel ventilation system in the process. It actually seems a lot more complex than it appears at first glance.




QUOTE=bmwdirtracer;30990463]By the way, your original post said "expected pressure increase in the intake manifold", but the sensor you're referring to now isn't measuring pressure in the intake manifold; it's measuring pressure at the venturi nozzle. A MAP sensor in the manifold would certainly show a greater change than 0.4...but not necessarily so, for the venturi nozzle. Are you watching data for the venturi nozzle sensor, or the manifold, or the intake pipe? 3 different sensors, the three will show three different pressure readings. That's why Abel was asking for specifics....[/QUOTE]

[Kies277]

Another question regarding the Vent Valve. The bottom of the vent valve has a shutoff valve that controls when the vapor is fed directly into the throttle body. Can anyone tell me what circumstances causes that valve to open and/or close?

It appears to be normally closed so I am wondering what would trigger it to open.