02-17-2020, 09:03 AM | #1 |
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244C00 Charging Pressure Too Low
I have done some research following this one error that I am getting.
I took it to an indy who said that the Exhaust Pressure Sensor upstream of Turbo needs changing, and i got to this same stage in the test-plan using ISTA. It basically is not hitting the threshold consistently of 2500mbar and the difference between the charge being open and closed should be 1500mbar, and is sitting slightly lower than this. See graph attached: View post on imgur.com Vacuum pipes seem intact, intake seems to be OK, have tries changing MAP sensor, air filter and EPS before turbo with no luck. Error is intermittent, happens under moderate acceleration, and usually clears itself from iDrive after a few miles when engine is warm. DTC still stored in error memory however. When fault is present, loss of power occurs, small turbo (?) not kicking in. My assumptions is that the pressure is not being held so it leads me to the pressure converters for the turbos. Any help would be greatly appreciated |
02-17-2020, 10:15 AM | #2 |
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Has the intake tract been pressure smoke tested for leaks? This should be done.
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-2014 328d Wagon, 8HP. Self-tuned, 270hp/430ft-lbs.
-2019 M2 Competition MT, Alpine White. Self-tuned 560hp -2016 Mini Cooper S, MT. Many plans. Others: -E36 328is. 2000 Z3 Roady. 2003 VW Jetta TDI Manual. Estoril Z3M Coupe. |
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02-17-2020, 10:35 AM | #3 |
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I have not yet done a smoke test, however, I conducted the Air Soot buildup (i think that is what it is called) test plan which shows calculated air vs actual and the graph indicated that there is not a major issue - will upload once i get a chance
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02-17-2020, 11:24 AM | #5 |
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Taking into consideration that I have tried swapping the MAP and EGP sensor and the fault still persists suggests that the sensors are reading the correct value, so it’s pointing towards the pressure is actually too low.
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02-17-2020, 11:45 AM | #6 |
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The pressure sensor upstream of the turbo is somewhat removed from charging pressure.
EGR not fully closing when it is supposed to? Did you reset adaptations of MAF? Any leakage in the pressure hose or connection to the EGP? Or are you thinking there is not enough air pushing through the engine to reach the 2500 like a snowball effect? What's your mileage? |
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02-17-2020, 11:54 AM | #7 |
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The exhaust pressure being too low will effectively lead to charging pressure being too low as it won’t have the optimum pressure to turn the exhaust turbine, or am I wrong in saying that? Yes I did reset adaptations when I replaced the MAP (not MAF). As you suggest, the pressure could be low due to either the EGR valve not closing or the wastegate not closing properly. Are both EGR valves and wastegate valves controlled via the vacuum system? Car seems to be getting enough air as if it wasn’t I’m sure I would be getting subsequent errors for the intake system. Currently on 70526 miles, it started very intermittent and now occurs every time I get into the car from cold, accelerating up to about 40mph and varies but usually about 2k rpm triggers the fault.
The EGP is attached to a hose, no visible leaks and I did prod it with a hanger to see if it was blocked but was all OK |
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02-17-2020, 01:04 PM | #9 |
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I’m not sure about readings whilst it’s warm - ie driving, but after driving a short while it seem to hit the EGP threshold limit of 2500mbar, however the difference when the car is not under load does not hit the 1500mbar difference level by about 200mbar and states “Not OK” and ends the test plan there
Also when completely warm the drivetrain error will rarely come back until I let the car rest for a bit then drive again, it will intermittently come on which goes away with a few ignition cycles or driven a few miles Last edited by zaynn786; 02-17-2020 at 01:13 PM.. |
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02-23-2020, 04:00 AM | #10 |
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Bimmerlink has updated its iOS app to show EGP before turbo which is helpful however i now have another code showing error for the actual EGP. Does anyone know what the calculated pressure should be?
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04-17-2020, 10:24 AM | #12 |
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I will try to see if I have EGP sensor available in the app I use this afternoon. The boost pressures are about right, mine are at 100 kPa (1 bar) at idle. They increase significantly with greater acceleration. But I know exhaust pressure is what you're looking for, if I have it, I will graph it and get it to you on same graph with RPMs.
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04-17-2020, 10:29 AM | #13 | |
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04-17-2020, 05:03 PM | #14 |
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Well, the only exhaust pressure sensor I have available in the app I use is Exhaust Pressure Sensor Bank 1. It reports results in kPa which are tremendously low. What I think I will try to do is connect my laptop to the car to cross reference the sensor. I think the app reports the exhaust pressure in ba over barometric pressure. The barometric pressure sensor reported ambient pressure at exactly 100kPa or 1 bar.
Does it make sense for the pressure to be 1.45 bar at idle 780 RPM and rise to 1.95 bar at its highest at around 2400 RPM? Edit: The app really reduces image size. I uploaded original here https://ibb.co/kG7Mvds |
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04-20-2020, 05:34 AM | #15 | |
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04-20-2020, 06:09 AM | #16 | ||
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I have 328d with 4 cyl N47T engine. |
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04-23-2020, 07:48 AM | #18 |
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Another set of data points from this morning - rainy day, so did not take any screenshots. However, to compare boost pressure to EGP:
In my N47, EGPs are ALWAYS higher than boost pressures, but not significantly. Variation is usually EGP 0.05-0.1 bar higher than boost pressures. Boost pressures respond in the same way as EGP to "throttle" - very comparable graphs with no noticeable deviation. Boost pressures read around 1.02 bar at idle, 1.2 bar cruising at 70 mph, and 3.4 bar when giving throttle for quick 60mph to 70mph highway acceleration. So I would imagine your boost and EGP should respond in the same way and should rise well over 2bar on quick acceleration. Hope this helps. Let me know if you need any more data points, I realize we have different engines, but maybe this helps to pinpoint the issue. |
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04-27-2020, 11:19 AM | #19 | |
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04-27-2020, 02:45 PM | #20 | ||
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05-06-2020, 07:52 AM | #21 |
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@Zynn786 and eugene89us - Thanks for posting this, I have been getting this exact same thing for years now in my 535D, never really caused much of a problem so left it alone as the list of possible causes was large! I just got fed up with it again and happened on your post which will be great for helping me investigate.
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10-16-2020, 12:09 PM | #22 |
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Problem got fixed in April, and has returned with the same codes, charging pressure too low and EGP deviation. Changed pressure converter for one turbo wastegate, I suspect the other turbo is now exhibiting the same problem. Will update as I go
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