Bmw N55 Intake Pipe Vacuum Sensor

By | July 1, 2022

OK I’m hither to revive this post to share some of my experience and find some help.
My car is 2011 335i N55 coupe 65k miles. All stock except a VRSF chargepipe.
Codes that I’ve already stock-still or maybe fixed (the code never pops upwardly merely some bug remain) are:
p112f (intake manifold pressure besides high)—alter cracked stock chargepipe and MAP sensor on it
p325f (plausibility of fuel pressure)—change loftier pressure fuel pressure sensor

Both codes can put the auto into limp mode when I press gas pedal hard, no matter high speed or low speed. Gentle acceleration is fine. No noticeable loss of power. It’south been 3 months and 1 calendar month since the 1st and 2nd repair: above ii codes never come back.

At present the car got 2 new codes:
2C57 (charge pressure level too low)
2906 (suspicion of leaks between turbocharger and intake valves). They dont put automobile into limp way merely a half engine calorie-free (disappear afterwards restarting the car). Here is my work on the verification:

  1. Clear the codes.
  2. Wide open up throttle (WOT) from 0mph to 60mph, no mistake.
  3. Prowl at 60mph for a while and WOT from 60mph to 100mph, engine light is on somewhere betwixt 80mph and 100mph
  4. stop, read codes

I repeated the above process 3 times on 3 separate days, same problem, same codes (2c57, 2906)

I used an Autophix ES910 OBD reader to run into the codes and datastream. Online values may fluctuate a petty but the trend is firm.

  • Ambient pressure level: 1010hpa (14.6 psi)
  • idle-3k rpm:
    • intake manifold pressure later on throttle valve: 955.47hpa (13.9psi)
    • intake pipe vacuum before throttle value: 1005.23hpa (14.6 psi)
    • intake pipe vacuum upstream of throttle valve: 1005.55hpa (fourteen.six psi)
  • 3k-4k rpm:
    • intake manifold pressure afterwards throttle valve: 1000hpa (fourteen.5psi)
    • intake pipe vacuum earlier throttle value: 1020hpa (14.8 psi)
    • intake pipe vacuum upstream of throttle valve: 1060hpa (xv.iv psi)
  • 4k-five.5k rpm (above 80mph, engine throws error codes here. No error below 80mph):
    • intake manifold pressure afterwards throttle valve: quickly boosted from 1000 to 1400hpa (xiv.v-20.3psi)
    • intake pipe vacuum before throttle value: quickly boosted from 1020 to 1500hpa (14.8-21.8 psi)
    • intake pipage vacuum upstream of throttle valve: quickly boosted from 1060 to 1500hpa (15.four-21.8psi)
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Here are my questions:

  1. It looks like code 2C57 and 2906 should evidence up every bit twins? I don’t know if this 2-code situation is dissimilar from the just 2C57 lawmaking.
  2. Stock MAP sensor reads upwards to 22psi. Stock turbo boosts upwardly to 8 psi. Considering the ambient pressure level 14.6psi, the max possible boost absolute pressure read from MAP sensors is about the sensor limit 22psi. My car tin can boost up to 21.8psi, which looks practiced. Even so, there is no boost while cruising (beneath 3k rpm, MAP sensor reading <= ambient pressure level). What are correct MAP sensor readings at different rpms? Anyone share their data?
  3. If at that place is boost leak, is information technology possible that our cars can still become to 22psi? Whatever suggestions on how to do a quick and easy leak check (non pricey)?

What I volition do adjacent, is to change the pneumatic force per unit area converter mentioned in this post. Information technology is prone to fail then I have to change it anyhow even though information technology still works now. If the problem remains, I will do a thorough leak exam and come across what is going on. I will keep updating until it is solved (hopefully
). Any comments and supports volition be highly appreciated!