Reduced power, no check engine and no fault codes

Skiendziel · 07-31-2024, 03:36 PM

BMW X1 F48 B47 1.8d engine

Dears,

3 months ago, I bought my F48 with 1.8d engine (150 HP). The year of production is 2015 with just 50 000 km. It was perfectly fine with one problem that I found out one night (after reading numerous articles about this model) - it turned out there is a fuel in engine electric harness. I immediatelly found some service that specializes in BMWs and ordered fuel sensor and harness replacement.

My mechanic also checked ECU and found some fuel there as well, so it was cleaned. After few days, I took my car but I felt that it wasn't behaving in the same way as before. I decided to make some tests and it turned out that it is not achieving neither its max power (180 km/h instead of 204) nor acceleration (12-13 seconds to 100 km/h). Thus, I asked my mechanic to check it again.

There are no fault codes, which makes it even more difficult to determine what is a root cause. What is more, a lot of things have been checked so far with no success... ECU is ok (test with the part from other car). It seems there is also no problem with EGR (test with the part from other car). Some testing of air pressure after turbocharger was promissing - it turned out that the turbo does not reach appropriate pressure when accelerating, but we have checked the actuator and it is ok. It also appears that the intake system is tight.

Can it be the problem with the parts that were changed, especially with the low pressure fuel sensor (original OEM part was used)? Could something went wrong during replacement? Did something similar happened to you? I will be grateful for any hints, as this situations starts to make me crazy...

Skiendziel · 10-16-2024, 03:55 PM

Hello Guys,

Some more information. It seems my charging pressure is too low (red line):

Blue line represents exhaust pressure before turbo and grey line represents fuel supply. Test was made with full pressure on the gas pedal.

Turbo is ok, so I turned my attention to the fuel system. I have 2 concerns. First of all, my rail pressure does not achieve 2000 bar (although its values fully match setpoints). The second concern is that my fuel quantity control valve is bouncing on idle. Is it normal?

Red -> enigne speed
Black -> rail pressure
Green -> fuel injection volume (3rd axis)
Orange -> rail pressure setpoint value

Red -> engine speed
Dark red -> fuel quantity control valve (it is bouncing)
Blue -> set point for dark red
Black -> rail pressure

What do you think about it? Do you see anything disturbing here?

07-31-2024, 03:36 PM	#1
Skiendziel Registered 0 Rep 2 Posts Drives: BMW X1 F48 Join Date: Jul 2024 Location: Warsaw iTrader: (0)	Reduced power, no check engine and no fault codes BMW X1 F48 B47 1.8d engine Dears, 3 months ago, I bought my F48 with 1.8d engine (150 HP). The year of production is 2015 with just 50 000 km. It was perfectly fine with one problem that I found out one night (after reading numerous articles about this model) - it turned out there is a fuel in engine electric harness. I immediatelly found some service that specializes in BMWs and ordered fuel sensor and harness replacement. My mechanic also checked ECU and found some fuel there as well, so it was cleaned. After few days, I took my car but I felt that it wasn't behaving in the same way as before. I decided to make some tests and it turned out that it is not achieving neither its max power (180 km/h instead of 204) nor acceleration (12-13 seconds to 100 km/h). Thus, I asked my mechanic to check it again. There are no fault codes, which makes it even more difficult to determine what is a root cause. What is more, a lot of things have been checked so far with no success... ECU is ok (test with the part from other car). It seems there is also no problem with EGR (test with the part from other car). Some testing of air pressure after turbocharger was promissing - it turned out that the turbo does not reach appropriate pressure when accelerating, but we have checked the actuator and it is ok. It also appears that the intake system is tight. Can it be the problem with the parts that were changed, especially with the low pressure fuel sensor (original OEM part was used)? Could something went wrong during replacement? Did something similar happened to you? I will be grateful for any hints, as this situations starts to make me crazy...
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10-16-2024, 03:55 PM	#2
Skiendziel Registered 0 Rep 2 Posts Drives: BMW X1 F48 Join Date: Jul 2024 Location: Warsaw iTrader: (0)	Hello Guys, Some more information. It seems my charging pressure is too low (red line): Blue line represents exhaust pressure before turbo and grey line represents fuel supply. Test was made with full pressure on the gas pedal. Turbo is ok, so I turned my attention to the fuel system. I have 2 concerns. First of all, my rail pressure does not achieve 2000 bar (although its values fully match setpoints). The second concern is that my fuel quantity control valve is bouncing on idle. Is it normal? Red -> enigne speed Black -> rail pressure Green -> fuel injection volume (3rd axis) Orange -> rail pressure setpoint value Red -> engine speed Dark red -> fuel quantity control valve (it is bouncing) Blue -> set point for dark red Black -> rail pressure What do you think about it? Do you see anything disturbing here?
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