Uploaded August 2019 | Updated September 2026, 1 week ago
I started looking at the MAP sensor as I initially thought it may be leading to a low turbo pressure and smoke from the exhaust. I even bought a new MAP sensor but it didn’t make any difference, so I did this test to check the sensor. It’s fairly easy, confirms it’s operating correctly or not and should save you arbitrarily buying a new part!
Just compare your sensor output voltages at a particular pressure with the graph of volts versus pressure (in psi) shown in the video.
If you want a better printable copy of that MAP pressure/voltage graph I’ve made a download area, with just a small charge for my time - £1.99 via PayPal (nice and safe) use the link below and you’ll get instant access to the document in 3 formats. The files are in universally readable pdf format, the Apple ‘Numbers’ and ‘Excel’ format. No material is posted, just download access. The payment link is set up to accept PayPal or any credit card and so is very safe. You will be directed to the files after you have paid and clicked on “return to merchant” it will take you to a page by Dropbox, then just click on “continue to website” (or download Dropbox app if you want) and you will then see the files which you can open up to view or you can download them to your device.
Here it is: bit.ly/MapGraph
If you do find after testing that you need a new MAP sensor then see here for the best price on eBay U.K.:
ebay.us/bcAdsG
When talking about pressure please note the difference between absolute and relative pressures. The normal atmosphere pressure at sea level is about 15 psi. That graph I showed of pressures is absolute pressure, i.e. the pressure relative to a vacuum. So that is why the MAP sensor reads 1.77 volts when it is just open to the air as that is the voltage for 15 psi of absolute pressure. When you use a tyre gauge to pressurise it, the tyre gauge reads relative to atmospheric pressure (i.e. the amount over atmospheric pressure), so 15 psi on the tyre gauge is about 30 psi absolute pressure.
This video is part of a series of investigations I did to try and improve and eventually remove the exhaust smoke coming from this TD4 (BMW engine) freelander. Hence I suppose you could call this “smoke reduction stage 6”.
Subscribe to the channel for similar DIY, fixing stuff, car bits and tech reviews here:
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Note, if you want to be notified of new videos click on the bell symbol on my home page.
See other videos on my channel here:
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If anyone wants to show appreciation for any money savings, or just help support the channel and future videos then you now can. Use this link: paypal.me/comeinhandy
OR you can support me by using the Amazon and Ebay links to buy other stuff that you would usually buy, it will not cost you anything more, but will help this channel. e.g. Generally useful stuff:
Face mask:
Amazon UK: amzn.to/2GHE9d6
Similar ones on Amazon USA: amzn.to/2IHmip1
Eye goggles: Amazon UK: amzn.to/2IUSqos
Amazon USA: amzn.to/2GAtIXJ
Rubber disposible gloves are also useful, to start you off here's the links for
eBay USA: ebay.us/GGqmTJ
eBay UK: ebay.us/cE1BHK
Amazon UK: amzn.to/3aikbl8
Amazon USA: amzn.to/3cdwjpD
Amazon Canada: amzn.to/2Q0VHZm
Amazon Australia: amzn.to/2QlUawX
A set of precision screwdrivers:
Amazon UK: amzn.to/2W311si
Amazon USA: amzn.to/2Z322T5
Torx bits sets:
Amazon UK: amzn.to/2Pgmf48
Or Amazon USA: amzn.to/2XlOK3h
I’m on Facebook here: facebook.com/comeinhandynow
Become a Patron to get extra content or previews or sponsor here: patreon.com/user?u=31365629&fan_landing=true
The video is about my personal opinion and experience and contains no paid for product placements. No responsibility is accepted for any perceived recommendation for or against a product or feature nor any consequential damage or harm since this video is just my personal experience. You accept by watching this video that you accept any responsibility for any subsequent actions or decisions that you take.
Note on copyright / licensing: This video was created using Apple iMovie and as such any music or video content is fully licensed by their terms and conditions for free publication and distribution.
See the Apple iMovie software license agreement at:
images.apple.com/legal/sla/docs/iMovie.pdf
Which states "all Sample Content included in the Apple Software may be used on a royalty-free basis in your own video projects"
Specifically the following background music from Apple iMovie soundtrack “Interludes” by Daniel Garrow is used royalty and copyright free under the above Apple license.
I started looking at the MAP sensor as I initially thought it may be leading to a low turbo pressure and smoke from the exhaust. I even bought a new MAP sensor but it didn’t make any difference, so I did this test to check the sensor. It’s fairly easy, confirms it’s operating correctly or not and should save you arbitrarily buying a new part!
Just compare your sensor output voltages at a particular pressure with the graph of volts versus pressure (in psi) shown in the video.
If you want a better printable copy of that MAP pressure/voltage graph I’ve made a download area, with just a small charge for my time - £1.99 via PayPal (nice and safe) use the link below and you’ll get instant access to the document in 3 formats. The files are in universally readable pdf format, the Apple ‘Numbers’ and ‘Excel’ format. No material is posted, just download access. The payment link is set up to accept PayPal or any credit card and so is very safe. You will be directed to the files after you have paid and clicked on “return to merchant” it will take you to a page by Dropbox, then just click on “continue to website” (or download Dropbox app if you want) and you will then see the files which you can open up to view or you can download them to your device.
Here it is: bit.ly/MapGraph
If you do find after testing that you need a new MAP sensor then see here for the best price on eBay U.K.:
ebay.us/bcAdsG
When talking about pressure please note the difference between absolute and relative pressures. The normal atmosphere pressure at sea level is about 15 psi. That graph I showed of pressures is absolute pressure, i.e. the pressure relative to a vacuum. So that is why the MAP sensor reads 1.77 volts when it is just open to the air as that is the voltage for 15 psi of absolute pressure. When you use a tyre gauge to pressurise it, the tyre gauge reads relative to atmospheric pressure (i.e. the amount over atmospheric pressure), so 15 psi on the tyre gauge is about 30 psi absolute pressure.
This video is part of a series of investigations I did to try and improve and eventually remove the exhaust smoke coming from this TD4 (BMW engine) freelander. Hence I suppose you could call this “smoke reduction stage 6”.
Subscribe to the channel for similar DIY, fixing stuff, car bits and tech reviews here:
youtube.com/user/comeinhandynow?sub_confirmation=1
Note, if you want to be notified of new videos click on the bell symbol on my home page.
See other videos on my channel here:
youtube.com/user/comeinhandynow
If anyone wants to show appreciation for any money savings, or just help support the channel and future videos then you now can. Use this link: paypal.me/comeinhandy
OR you can support me by using the Amazon and Ebay links to buy other stuff that you would usually buy, it will not cost you anything more, but will help this channel. e.g. Generally useful stuff:
Face mask:
Amazon UK: amzn.to/2GHE9d6
Similar ones on Amazon USA: amzn.to/2IHmip1
Eye goggles: Amazon UK: amzn.to/2IUSqos
Amazon USA: amzn.to/2GAtIXJ
Rubber disposible gloves are also useful, to start you off here's the links for
eBay USA: ebay.us/GGqmTJ
eBay UK: ebay.us/cE1BHK
Amazon UK: amzn.to/3aikbl8
Amazon USA: amzn.to/3cdwjpD
Amazon Canada: amzn.to/2Q0VHZm
Amazon Australia: amzn.to/2QlUawX
A set of precision screwdrivers:
Amazon UK: amzn.to/2W311si
Amazon USA: amzn.to/2Z322T5
Torx bits sets:
Amazon UK: amzn.to/2Pgmf48
Or Amazon USA: amzn.to/2XlOK3h
I’m on Facebook here: facebook.com/comeinhandynow
Become a Patron to get extra content or previews or sponsor here: patreon.com/user?u=31365629&fan_landing=true
The video is about my personal opinion and experience and contains no paid for product placements. No responsibility is accepted for any perceived recommendation for or against a product or feature nor any consequential damage or harm since this video is just my personal experience. You accept by watching this video that you accept any responsibility for any subsequent actions or decisions that you take.
Note on copyright / licensing: This video was created using Apple iMovie and as such any music or video content is fully licensed by their terms and conditions for free publication and distribution.
See the Apple iMovie software license agreement at:
images.apple.com/legal/sla/docs/iMovie.pdf
Which states "all Sample Content included in the Apple Software may be used on a royalty-free basis in your own video projects"
Specifically the following background music from Apple iMovie soundtrack “Interludes” by Daniel Garrow is used royalty and copyright free under the above Apple license.
