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Barometric Pressure Sensor - possible alternative

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  • Barometric Pressure Sensor - possible alternative

    Hi guys, I posted this to the SIG email list, so please forgive the cross post if you've already seen it, but I would love to get some additional responses to my survey. Thanks!

    Short version:
    Please answer this very short (1 minute) survey to help me decide whether to develop a new product for our e30 M3 community:

    Longer version:
    Most of you are familiar with the barometric pressure sensor, mounted on the driver's side of the engine compartment near the air flow meter. As you know there are concerns about possible engine damage occurring due to the sensor failing, causing the engine computer to think the car is at high altitude, and decreasing the fuel so the engine runs lean. For this reason, some folks recommend unplugging the baro sensor if most of your driving is done near sea level.

    I have been thinking for several years about developing a replacement barometric pressure sensor that would use robust modern solid state components, with the intelligence built in to compare multiple internal sensors and thus put out a safe level in the unlikely event that one of these more robust internal sensors fails. The sensor would also alert the owner to the problem with a buzzer and/or LED.

    As the owner of a product development consultancy, I have the capability to design and produce this new sensor, and I'm considering adding some internally developed products to our portfolio. My company ( typically provides engineering services for startups and other companies, such as circuit board design, software development, mechanical engineering, and integration of all of the above.

    I am trying to determine if there is sufficient interest for me to proceed with developing this new replacement for the factory barometric pressure sensor. The e30 M3 was designed to adjust fuel and ignition timing based on the barometric pressure, which typically changes with altitude. I would personally like to have a functioning baro sensor without worrying about possible damage, and I suspect that many others would be interested too. However, I have put together this survey to confirm my suspicions before moving forward with developing the new sensor and then realizing I was the only one that wanted it.

    My replacement barometric pressure sensor would be plug and play, mounting in the stock location, with voltage output versus barometric pressure identical to the factory sensor. As the price of the factory sensor has continued to rise over the past few years, it has made me more and more hopeful that I could produce and sell a better functioning replacement that matches or potentially beats the price.

    I'm collecting email addresses with this survey only to enable following up with folks that are interested. I won't share your email address.

    For those of you that may not know me: I'm Dominic Germana, 11-year e30 M3 owner. I used to be very active here on the first few years I had the car, but kids and my business have pulled me away from forum participation a bit. I'm the founder/chief engineer of product development consultancy Impact Embedded, LLC.

    I would very much appreciate the participation of anyone who is willing to complete the survey. It's a google form and you can access it with this link:

    Please let me know if you have any questions, suggestions, or comments. Also, if anyone happens to have a new/known good factory sensor that I could borrow to take some measurements I would appreciate it. I have a few sensors here but it would be good to compare multiple sensors to make sure I have an accurate characterization.

    Thanks again very much!


  • #2
    My initial response: Aren't there already commercially available, inexpensive sensors that do the same thing? I am using a Delco MAP sensor with my current EMS, and I think it cost around $26.

    Or is your goal to design something that will plug into/talk to the stock Motronic with no software changes? So many cars of the era used baro sensors, my instinct is that you are re-inventing the wheel and that it cannot possibly be cost effective...but I would love to be proven wrong.


    • #3
      Thank you so much for your response. I intend to make a replacement for the stock sensor that would plug into the factory harness, mount in the same location, and not require any changes to the car. Most likely it will look close to identical as well. There's no intention to compete with sensors targeted at non-stock engine management systems. You're right that many cars of the era used baro sensors, and that actually makes me happy. I've learned that a number of other cars used the exact same part as the e30 M3, and of course there were many more of those other vehicles manufactured. I'm not sure why the stock sensors are now commanding such a high retail price, but my hope is that I can make something that will cost the same or hopefully less, to make it easier for folks to replace their failed sensors, rather than just leaving them unplugged. The fact that the new sensor should be more robust should make it easier for folks to choose it over the stock Bosch part. Thanks again for your feedback.


      • #4
        Mine broke after ~200'000 km, and I think I payed ~80 Euro (by seaching for the Bosch number on ebay).
        If the replacement last the same time, it will be a long time until I need one...
        On the other hand I permanently run a wideband with display as safety percausion, so should see straight when somethings wrong.