Thread: Cleaning a TDV6 MAP sensor

Originally Posted by wyperfield

While browsing the DISCO3.CO.UK for something I came across this thread on cleaning the MAP sensor. Maybe there is a thread on it here, but I have not seen it.
So, I checked mine out this morning and it was dirty just like the pics on the thread. I cleaned it with a squirt of brake cleaner, a rag and a bit of wire, taking about 10 minutes max.
Well, what a difference ! No noticeable change in power or acceleration but I filled up & reset the trip readings and it was showing after 1/2 hour on the freeway an average of 7.7 l/100klms. I have not had it that low for ages. Maybe there was a tailwind and its just a coincidence, but it seems very strange.
Definitely worth doing as it costs nothing.

Here is the link DISCO3.CO.UK - View topic - Go and clean you MAP Sensor NOW!!!

A piece of wire! you may have in fact damaged the sensor.
From what I have read never poke anything down the hole, I used electrical contact cleaner only with shaking off excess to remove the dirty fluid.
Yes I too have had an improvement:
http://www.aulro.com/afvb/d3-d4-rrs/...ml#post1553547

I cleaned the MAP sensor in my D3 before I sold it. After 137,000km - not much gunk on it at all.

I cleaned mine a few months ago - no noticeable change - but then again my D3 always runs pretty well....or maybe I'm just easily pleased after 20 years driving an underpowered VW campervan !!!
cheers

Cleaned mine after reading this. The MAP sensor was very dirty. I’d to know if cleaning other parts of the intake was this easy.

Wouldn't the LR D4 brain throw up a fault if the blocked MAP sensors had an effect on performance?

I get that it does not look pretty all gunked up, but if "it ain't broke" ?

Cheers
Scomac

Originally Posted by scomac

Wouldn't the LR D4 brain throw up a fault if the blocked MAP sensors had an effect on performance?

I get that it does not look pretty all gunked up, but if "it ain't broke" ?

Cheers
Scomac

Spot on. Cleaning it is likely only impacts aesthetics. The gunk within is still permeable and flexible and thus the pressure still acts upon the sensor. If it wasn’t working correctly you’d get a P006A algorithmic failure error like when there is an intake air leak, which is the system saying the MAF and MAP sensors are not aligned. The MAP sensor as I understand it is there as a protection mechanism for sensing leaks mainly, rather than a primary sensor as MAF plus RPM, air temp and other sensors will determine the actual air being ingested. That is cross checked with the expected manifold air pressure at the MAP to determine issues (leaks).
These statements of mine are educated assumptions knowing how cheap a MAP sensor is compared to a pair of MAF sensors, plus the redundancy of each (you can use MAP solely if you like, you just have to retune for every change to engine volumetric efficiency). MAF is always preferred as it ensures the engine tune is accurately maintained throughout the life of the vehicle and its health. Also keeping a solely MAP based car in tune and meeting emissions long term in places where there are annual tests is much harder.

The idea for MAP cleaning came from people getting errors that were fixed by cleaning. Most likely with the older style that has a much smaller opening. So the idea is really a preventative action that may not be required with the newer type but in my view still good practice.

Scott

Originally Posted by LRD414

The idea for MAP cleaning came from people getting errors that were fixed by cleaning. Most likely with the older style that has a much smaller opening. So the idea is really a preventative action that may not be required with the newer type but in my view still good practice.

Scott

Makes sense.