Boost sensor (MAP) issues

[first-things-first]

See here for earlier instances of this issue - https://the75andztclub.co.uk/forum/s...d.php?t=271494.

I was getting a "check engine" warning and TOAF (Android) gives a "0235 - Boost pressure sensor" error (nothing else present).

I have taken the MAP sensor off and cleaned it gently. It had oil crud on it, but the sensor hole was not caked in the stuff and not blocked.

After cleaning, the car did seem to get on boost earlier and better. No sign of the error now. I have screenshots of TOAF. The "air pressure sensor" reads "high" - around 4100+ HPa (millibar) (or is it normal?).

Here's the before (cleaning and error clear) values and graph plot of me giving it some revs to 2000 rpm.

[first-things-first]

Values and graph plot AFTER I cleaned the MAP sensor and cleared the error. The graph plot is me revving to 2000 rpm then after wards revving to 3000 rpm and holding for a while.



Does this look fine now? Should I replace the sensor, or would a periodic clean be just as good?

[grivas]

Originally Posted by first-things-first

See here for earlier instances of this issue - https://the75andztclub.co.uk/forum/s...d.php?t=271494.

I was getting a "check engine" warning and TOAF (Android) gives a "0235 - Boost pressure sensor" error (nothing else present).

I have taken the MAP sensor off and cleaned it gently. It had oil crud on it, but the sensor hole was not caked in the stuff and not blocked.

After cleaning, the car did seem to get on boost earlier and better. No sign of the error now. I have screenshots of TOAF. The "air pressure sensor" reads "high" - around 4100+ HPa (millibar) (or is it normal?).

Here's the before (cleaning and error clear) values and graph plot of me giving it some revs to 2000 rpm.

Hi, how did you clean the MAP sensor please?.

[first-things-first]

Hi. I used some brake cleaner (carb cleaner / isopropyl alcohol / WD40 should work as well) to wipe the residue off the housing and the sensor opening. Don't poke anything inside the sensor opening.

I also cleaned the manifold sensor hole.

[Arctic]

As above once you have the MAP sensor of the manifold, wipe off any crud with a rag sprayed with carb cleaner, do not poke anything into the air hole.

clean and gunk one nest to each other.
1

2

3

This is what is inside of a MAP sensor.
4

But lets remember that the EGR and manifold should be clean also.
5

6

[grivas]

Originally Posted by Arctic

As above once you have the MAP sensor of the manifold, wipe off any crud with a rag sprayed with carb cleaner, do not poke anything into the air hole.

clean and gunk one nest to each other.
1

2

3

This is what is inside of a MAP sensor.
4

But lets remember that the EGR and manifold should be clean also.
5

6

Thank you for the pictures of the MAP sensor interior, how do you disconnect the wiring plug from the MAP sensor, it looks like a wire lock, do you pull this wire clip straight out then push down to release?.

[first-things-first]

The wire clip sits in a slot and is spring loaded and just pushes down and that allows you to pull the plug off (whilst holding it down).

At first I used to use a screwdriver to remove it (and of course it would fling off). Doh

[Arctic]

As above it is a spring which you just press inwards, then with your other hand and a flat blade screwdriver push the plug downwards.

1

2

You will find it very difficult to remove the MAP sensor in situ while the manifold is still attached to the engine, it can be done but is not easy, i made a special to do it, not that i have had to do to many.

I have always removed them after changing out the manifold for a clean one.
3

[grivas]

Originally Posted by Arctic

As above it is a spring which you just press inwards, then with your other hand and a flat blade screwdriver push the plug downwards.

1

2

You will find it very difficult to remove the MAP sensor in situ while the manifold is still attached to the engine, it can be done but is not easy, i made a special to do it, not that i have had to do to many.

I have always removed them after changing out the manifold for a clean one.
3

Thank you once again, that is extremely helpful, I will consider removing and cleaning the manifold, but will leave it until later on, this post is been excellent, thanks.