N54 fuel pressure at idle. Feels like misfires when under mild acceleration.
N54 fuel pressure at idle Details on the car: Early F10 N55 with rotary n54 style HPFP Only mod is VRSF Catless downpipe and OEM M5 Mufflers Coils/plugs/injectors are relatively new (OEM BMW parts) Stage 2 MHD 91 Octane tune at the moment May 26, 2021 · I know for rail pressure, the maps used by the dme are the external maps (BMW), meaning its the maps with all caps abbreviations. description: I am getting an occasional misfire when turning right. Today had strange thing happening with rail pressure. To regulate the pressure, an electromagnetic (bypass) valve, […] A sudden drop from 3000 psi to low fuel rail pressure often indicates a failing high-pressure fuel pump or faulty fuel pressure sensor. recent work completed related to misfires: low pressure fuel sensor, new plugs, new coils, new turbos, new o2 sensors. 2010 BMW 335i M - Misfires across all cylinders, when I start it at idle it starts at 2200 psi and will settle down to around 700 psi at idle. For a while it sputtered while cranking, now it just cranks. So recently my car has been feeling horrible and having symptoms of HPFP failure :( : 1. Enjoy!! Dec 3, 2012 · I've been chasing an idle surge problem for a few weeks now, although it's hardly been a priority. Mar 20, 2023 · The high-pressure fuel pump (HPFP) is a common problem in the BMW N54 engine. Aug 1, 2023 · Hi Terry I am having issues where low side fuel pressure is reading 62-65 psi at idle when actual fuel pressure is at 72 idle when measured at rail with gauge. Is it a CEL Hi all, I'm new to bmws and own a 2007 335i running on stage2* mhd with fmic and cdp. I'm glad to see your rest pressure is more to your liking. once I Mar 21, 2014 · Not idle. the harder the lateral forces, the more it misfires. This can lead to poor performance and stalling, which is not something you want while cruising down the highway. Any ideas brethren? Jun 15, 2017 · Every N54 owner upgrade vaccum lines!twitter Facebook Digg Google StumbleUpon del. While some of the most common BMW N54 engine problems are the result of poor design at the hand of BMW and their parts suppliers, most of the problems listed May 23, 2024 · This value represents the fuel pressure supplied from the N54 high-pressure fuel pump. Jan 16, 2025 · Explore common BMW N54 engine problems, their symptoms, and potential consequences to stay informed and maintain performance. BMW N54 2008+ This is a 6-cylinder engine with a capacity of 2979 cc. 7 psiBMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i) > Technical / Specific Topics > 135i Turbo Engine (N54 / N55), Exhaust and Drivetrain Modifications Datalog shows LPFP sensor pinned at 55. While the BMW N54 is considered one of BMW’s most modifiable and power-capable turbocharged engines, it does come with its fair share of problems. I believe most fuel maps ramp up to 15-17 magapascals which is over 2k psi. The JB4 actually generates the HPFP pressure by reading the voltage of the pump. Mar 21, 2014 · Not idle. When already warm, my HPFP bounces back and forth between 700 to 2000s at idle. In this video we discuss the updated low pressure fuel sensor for the N54. One of the most worldwide issues is BMW N54 upper pressure fuel pump Dec 19, 2020 · - Fuel trims are expressed in percentages; a positive value indicates lean (DME is adding fuel) and negative values indicate rich (DME is subtracting fuel). Didn't notice a difference and occasional misfires still happened. Mar 29, 2022 · Hi all,I want to share some good tips on how to test GDi high-pressure pumps and injectors with scanner pids. It is a 6-cylinder in-line engine driven by a timing chain timing system. Mar 4, 2024 · N54 Common Problems: The Dreaded Trio High-Pressure Fuel Pump (HPFP) Failure: The N54’s HPFP has a reputation for early failure. In the picture: Rail pressure sensor is marked. The time now is 05:21 AM. The time now is 05:04 PM. If I throw in some starting fluid on the air filter it fires right up for about 1-2 seconds. us My Yahoo! Jul 2, 2017 · The car is throwing codes P2098,P2271 (bank 2) - OR - P2096 and P2270 (bank 1), seemingly depending on whatever mood the car seems to be in that day. The fuel pump is an essential component for your engine, as it supplies the motor with the necessary fuel to run correctly. May 14, 2025 · Your logs are definately pointing to an issue with your high pressure fuel pressure, whether it's the pump itself, it's wiring, or a fuse I can't say. g. Mar 7, 2015 · I know there are thousands of threads about the high-pressure fuel pump (HPFP) and that it fails. The high-pressure pump can deliver in excess of 3000 psi to the injectors, which can’t be measured with your conventional fuel pressure gauge. Jan 6, 2020 · 2008 535i, N54 engine, 140k miles. The fuel trims are extremely high in both banks, averaging around 15% on one Jan 15, 2023 · What is symptoms of failing Fuel control module? Also hpfp psi drop how low?All times are GMT -5. Despite being central to delivering the precise high-pressure fuel required for the engine's direct injection system, its inherent design and operational demand Nov 20, 2019 · 1 BMW N54 Tuning Guide 2 Tuning Guide 2. Seems to be more noticeable in sport mode. com). Sometimes it also throws P0041. Is there an analogous limit for rail pressure? Thanks! May 8, 2020 · N54 having LPFP spikes over 110psi! 2007 335i e92 Fuel-it stage 3 LPFP 550 cc PI AIC2 Motiv- FF sensor Running e85 In the process of tuning my car, noticed the LPFP pressure was all over the place, dropping below 40 and spikes over 100psi, so I decided to replace the following: HPFP ( FCP Nov 25, 2019 · Cranks but does not start! Car = 2007 335i n54 sedan; Car died while driving. Exhaust Leak - have done a pretty thorough inspection and can't find anything. Is there an analogous limit for rail pressure? Thanks! May 26, 2021 · I know for rail pressure, the maps used by the dme are the external maps (BMW), meaning its the maps with all caps abbreviations. ). Fuel is supplied by the DME system. It’s an early model that uses the N54 type HPFP Mar 25, 2023 · I'm looking for some help to solve a rough idle issue I've had for a long time. If you actively prevent/reduce misfires, the engine is receiving proper lubrication and cooling, and there are no pressure leaks then the turbos and engine internals should last a long time. I am trying to diag a no/low rail pressure situation, cant get this car to start When cranking I see like 80-85 psi on the LPFP, but less than 100psi at the rail. I have a 2008 335i (N54). ] My LPFP is loud and clear Dec 27, 2018 · When running, in INPA "Actuator Activation 2 --> Status Fuel Control Valve", I see about 50,000 hPa at idle, but off-rev (as engine comes down) saw pressures as low as 5000-8000 revs, and during this time engine misses badly. WOT pulls up top downs to 52-56psi on Jb4 side but manual gauge seems to barley drop at all. us My Yahoo! We would like to show you a description here but the site won’t allow us. You need to log a proper pull. I have a new stage 3 fuel pump and yes both pump work independently and i just replaced the fuel pressure regulator as well as a new fuel pressure sensor im not getting any codes for it so at this point I'm at a loss at what to check next any ideas?. No cel codes. « Previous Thread Next Thread » N54 fuel pressure - does this look right? What's your Lpfp pressure in your N54 at idle? Trying to figure this outAll times are GMT -5. 3. Its operating order is 1-5-3-6-2-4. 2007 335i automatic MHD stage 2 catless down pipes DCI Charge Pipe with TIAL style BOV New plugs New coils anyone have Jan 28, 2025 · The N54 engine, in particular, is notorious for high-pressure fuel pump failures. The ECM meters the fuel output of the injectors using pulse width signals. . 3 Step 3 – What type of air intake is on the vehicle? 2. One of the most common issues is BMW N54 high pressure fuel pump Apr 11, 2022 · To ensure the fuel supply, engine control sends a message with a demand request to the electronic fuel pump control module EKPS via the CAN bus. The N54 Engine: An Overview The BMW N54 engine, a remarkable BMW engine, is a powerhouse of performance, featuring an aluminum open-deck block, forged crank, and rods, along with a thrilling twin-turbo system. I'm seeing big drops in rail pressure. Cranks ok but doesn't even try to catch -- long history -- BMW Mechanic's Assistant: It sounds frustrating to deal with your 2007 BMW 335i's starting issues. Owners frequently report that these injectors can fail, leading to rough idling, misfires, and poor fuel economy. 2011 535i high pressure fuel pump issueAll times are GMT -5. Carbon Build-Up Direct fuel injection engines, like the N54 and N52, are prone to carbon build-up on the Dec 22, 2017 · Hello I have 11' 335 E92 with N55, 79k miles. BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > What should fuel rail pressure be at idle? Apr 28, 2015 · N54 HPFP and LPFP - what to look for in your logs Oct 14, 2023 · twitter Facebook Digg Google StumbleUpon del. When it fails, symptoms like long cranking, low power, rough idle, and even engine stalling occur. According to the bentley manual you jump terminal 6 (red/violet wire) to terminal 2 (white/blue wire) with a fused jumper wire, preferably with a switch in line as well. While diagnosing my old, failing LPFP and upgrading the fuel pumps, I would still experience this, which makes me think it is something else not directly related to the fuel supply system, but maybe something electrical. Since all 3 components of DMTL have issues NOW (AFTER swap from MSV80 to MS D 80 DME), if faults did NOT appear BEFORE DME swap, then likely an activation by DME wiring issue. It has a long crank on all startups and I just noticed this morning it has a slight miss at idle. Easiest way is to use protools to prime the lpfp to set pressure. The HPFP is responsible for delivering fuel to the engine at high pressure. May 19, 2023 · What does a Lpfp do? The APR Low Pressure Fuel Pump (LPFP) Upgrade is designed to ensure the low pressure fueling system is capable of delivering the proper volume of fuel from the fuel tank to the high pressure fueling system under high demand situations. Check the fuel pump relay and wiring for continuity. If the HPFP fails, it can cause a loss of power and rough idling. If you can't flow enough fuel to no load idle properly, then it won't flow enough fuel to move under it's own power. Note that while many of these parameters are also present in other JB4 applications such as N20, N55, and S55 they may or may not retain the same meaning/use. Without a properly operating HPFP, your BMW will not live up to it’s full potential, and may not run at all! Symptoms of this problem include rough idling, reduced power, and May 4, 2017 · High Pressure Fuel Pump Issue - I can directly view fuel pressure using Torque, it holds steady around 700 psi at idle and jumps up around 2000 during WOT. Nov 24, 2020 · Hey there lads. The time now is 06:38 AM. May 2, 2022 · Took my car out of winter storage after installing a 535lph LPFP in it and started getting a new tune from Doc Vu. All was working perfectly , since one day I got "reduced engine power" fail on dash + car starts to drive like it has 1/3 of normal power. Nov 28, 2015 · BUMP instead of making new thread. It's gotten cold out here in NH and I feel like it is related to the temp, but can't say for certain. Jan 18, 2020 · You will need a fpr that can handle over 100 psi and set it for 75 psi static pressure when car is not running. The time now is 11:10 AM. Mar 28, 2025 · Owners often report issues related to fuel injectors, high-pressure fuel pumps, and turbochargers, which can lead to significant performance degradation if not addressed promptly. Nov 9, 2024 · High pressure fuel pump always running at 700-720 psi even under load All times are GMT -5. See Below for suggested LOW PRESSURE FUEL PUMP tests. The car starts normally and idles perfectly cold, then after a short drive e. 0-liter inline-six engine. Symptoms include long crank times, power loss, misfires, and potential engine damage. Is my HPFP going out?All times are GMT -5. The 45 psi you measured is the fuel pressure of the low-pressure fuel pump. Nov 15, 2021 · Hello, i am having an issue after letting off the throttle and easing back into the throttle the car will have a bucking feel to it. The time now is 07:57 PM. The structure of HPFP has described in BMW AG after-sales materials, but many nuances are left “behind the scene”. The time now is 08:42 AM. Of course there are many other things that may go wrong with your n54, but one thing remains true. Idle pressure is around 700 psi. [Clearly low fuel pressure, WITHOUT INPA, but CONFIRMED by INPA screens you attach. Jun 9, 2023 · The BMW N54 engine is widely seen in the BMW polity as a toxic lover. trueHey all, I've been trying to chase down a cold start issue on my 2008 N54 335xi, here are the symptoms; long cold starts - I can get on the throttle and it will typically fix the issue Rough idle on initial start the rail pressure drops to about 1 or 2 pretty quickly, quicker than I have ever seen it, upon shutting the engine down Once warm, it will cut out on pulls, sometimes, not every Apr 10, 2024 · « Previous Thread Next Thread » Bad fuel rail pressure sensor? My e93 335i N54 was running correctly for a total of three days until it decided it was time for the fuel system to fail again. But I can say that n54 hpfp's are notorious for failing. It will most likely adapt to your new pump after some Apr 19, 2019 · The most common BMW N54 engine problems include high-pressure fuel pump failure, wastegate rattle, clogged or leaky injectors, chargepipe failure, valve cover oil leaks, carbon buildup, VANOS solenoid failure, and water pump failure. Jul 1, 2025 · The high-pressure fuel pump (HPFP) is a critical, yet commonly problematic, component on BMW's N54 twin-turbocharged engine. Nov 20, 2020 · Hey there lads. Nov 11, 2001 · Hi everyone. Another option if you have the old style and want to upgrade is to get a used "new" line from ebay and a new new sensor, and be done for under $80 A new old sensor seems to be around $90 Nov 19, 2017 · Running too rich - High negative fuel trim corrections can be caused by MAF sensor problems, high fuel pressure, leaking fuel pressure regulator diaphragm, faulty evaporative emissions components, leaking injectors, defective O2 sensors, exhaust leaks/pinholes before the O2 sensor, coolant temp sensor problems, and base engine issues such as Mar 25, 2019 · In the N54 it's a multiplier applied to the fuel demand calculation (based on brake specific fuel consumption of gasoline for a stock car). My tuner thinks its the HPFP and so do I but since I just installed the new LPFP I was wondering if there's anything I should check before I Oct 28, 2021 · How To Replace The Low-Pressure Fuel Line On A BMW N54 (fcpeuro. Depending on the type of electric fuel pump control, this message describes the setpoint value of the delivery rate (speed control) or a specification using pulse width modulation (pressure regulation). icio. us My Yahoo! Mar 25, 2024 · However, like any innovative technology, the N54 is not without its own challenges. But when I turn off the car, it dips to 100 psi immediately. The time now is 06:06 PM. They may be out of date, let me know if any if anything is wrong or could use updated. Do not run the motor! If you check the pressure while the engine is running at idle the pressure will read low because vacuum applied to the regulator reduces fuel pressure. This car has been to 4 shops on many occasions as well as me trying to troubleshoot. The time now is 04:31 AM. Jan 15, 2013 · Yes you pull the relay and jump the pins. Fingers crossed that’s the easy fix. Sep 1, 2023 · The BMW N54 has two separate fuel pumps: a high-pressure fuel pump (HPFP) and a low-pressure fuel pump (LPFP). Aug 21, 2018 · The HPFP, also called an injection pump, is an inherent feature of all direct-injection engines (such as the N54 & N55) and is not directly related to turbocharging. The HPFP pressure is maintained with a closed-loop system. When it’s going well it’s going great, however, the N54 can deal some pretty devastating blows too. Sep 30, 2024 · What is a map sensor BMW? The manifold absolute pressure (MAP) sensor, is located on or around the intake manifold, and provides constant information concerning the amount of pressure inside the intake manifold. All times are GMT -5. Found in popular BMWs like the 2007-2010 135i, 335i, 535i, and Z4 sDrive35i, the N54's twin-turbocharged performance comes with this inherent Achilles' heel. 2 Step 2 – What fuel is the vehicle using? 2. I've been trying to figure this out for a long time. Diagnosis involves specific scanning for fuel pressure deviations an I replaced my coils and plugs for some routine maintenance after it started idling rough/random sputtering start ups and when I took it for a rip I noticed while logging that my low side fuel pressure was 0 psi only touching 1 psi occasionally. BMW’s own recommendations for maintenance are crucial for keeping the N54 running smoothly. I do experience stuttering in a sense when accelerating. Pressure all seemed good until I was coasting down a hill and I watched my pressure drop to ~200 and jump to ~750 Datalog shows LPFP sensor pinned at 55. ISTA and INPA shows only codes for too low rail fuel pressure (P302C and P15DF in INPA). On the N54 Fuel trim banks refer to the 3 cylinder banks related to each turbo. If you suspect a HPFP failure, you should have it diagnosed by a mechanic. N54 Fuel-related fault codes and symptomsAll times are GMT -5. For some reason I cant hit 70 psi on the lpfp during a pull. I upgraded to the newer style sensor a couple years back and eventually developed Fuel Pressure Regulator or Pump ?All times are GMT -5. But that is exactly the problem: After browsing so many search hits, I have not been able to find a conclusive description of the early symptoms or the typical chronology of a failure. seem to be the worst at idle. No issues with straight pump e10 but that’s not what I run. once I Jul 5, 2023 · The Low Pressure Fuel Pump is located INSIDE the fuel tank, in the RIGHT half/ side of the tank. This critical component, located inside the fuel tank, is a frequent failure point on N54-powered BMWs (135i, 335i, 535i, X6, etc. Have any diagnostic codes been retrieved from the vehicle's computer? Customer: yes - Mechanic's Assistant: Could you please share Nov 16, 2016 · This is a list of codes I found online. Second, the Angle of Throttle Valve and Intake Pressure Sensor codes happened at the same time. Addressing this critical component promptly is essential to maintain engine performa « Previous Thread Next Thread » Fuel Mode 22 and Rail Pressure Spike at Idle May 6, 2021 · Lean condition on n54All times are GMT -5. Here is a quick reference to the JB4 N54 logging parameters and their general meaning as of ISO v31 firmware. It doesn't exactly correlate with STFTs or anything of that nature, nor can you blanket multiply the scalar based on logs. What happens if you unplug a mass air flow sensor while running? If you unplug the mass air flow sensor the car will start. The time now is 12:49 AM. Wondering what should rail pressure show upon start up? May 4, 2019 · twitter Facebook Digg Google StumbleUpon del. So to recap maintenance intervals for a stock N54: Mar 16, 2022 · Have replaced valve cover, all O2 sensors, one cat, low pressure fuel pump, high pressure fuel pump, cooks, plugs , injectors and more. Keeps rising up to 2300ish psi and injectors start ticking like crazy at Idle. Fuel Quality: Poor or contaminated fuel can reduce pump lifespan. Fuel trims are generally calculated by using a wide set of data values, including pre-cat O2 sensors, intake air temperature/pressure, ECT, knock sensors May 22, 2024 · The BMW N54 engine is widely seen in the BMW community as a toxic lover. Luckily, BMW extended the warranty on affected pumps and several improved versions exist for long-term reliability. Sep 1, 2023 · « Previous Thread Next Thread » N54 hiccups tiny misfires? idle not smooth « Previous Thread Next Thread » N54 running rough ! Need help In this entry – about one of the most expensive hubs of direct injection engines: high-pressure fuel pump. From everything I've read, this is normal operation. Jun 19, 2020 · Vacuum lines are relatively new, I will still look them over (again), and the boost leak test revealed that the system appears to be holding pressure. Adaptions reset. 4 Step 4 – Calibration refinement on a load-based chassis dynamometer. The high-pressure fuel pump sits on the driver's side of the engine, beneath the intake manifold. us My Yahoo! E90 335i N54 lpfp idles at 32 psi I use Bimmerlink to monitor temps, psi, etc. It has an aluminum cylinder head with 4 valves per cylinder. Sep 30, 2020 · Seems like the LP might be supplying enough fuel to the system to keep running during idle and moderate cruise, but anything requiring more fuel from a bad high pressure pump is starving the system (or a bad high pressure sensor makes the DME think there isn't enough pressure). I was data logging on my way to work to check fuel pressure because of my 2fca, and 2fda codes. Because of this, there are many misunderstandings and wrong decisions, performing the repair […] Nov 20, 2019 · 1 BMW N54 Tuning Guide 2 Tuning Guide 2. To measure the pressure, the pressure sensor, located in rail, is used. I cleaned the vanos solenoids as a quick fix after the car threw the code associated with them and didn’t notice a difference besides it didn’t go into limp mode anymore. Car runs fine. No changes. HexidecimalDecimalDescriptionNotes It would cause a slightly rough idle (jumped about 100-200 RPM during misfire). true2011 F25 N55 96K miles I’m trying to trouble shoot some rough idle and hard starts when cold. I saw my hpfp sit at 700 psi on idle and my lpfp was sitting at 32-34 psi on idle. Dec 3, 2022 · The High pressure fuel pressure sensor which is on the back of the fuel rail is on its way. I put Liqui Molly Jectron fuel injection cleaner in the fuel. In some cases, the engine may not start at all. I have a bucketed 535 with a healthy hpfp and Im usually at 1800 psi under high load and rarely might drop to 1500 rail pressure on e60. Jul 28, 2023 · N54 throttle delay/hesitation. I can hear an extra loud ticking (way louder than normal DI tick) when it spikes. Ignoring it leads to drivability issues, potential high-pressure f My OEM n54 always targeted "low" (say ~700psi) DI rail pressures on idle and ramped up with load to ~2500psi. May 10, 2023 · One of the most prevalent issues with the N54 engine is high-pressure fuel pump (HPFP) failure. The time now is 01:58 PM. Dec 11, 2020 · What are my options to increase fuel rail pressure?All times are GMT -5. Symptoms of this issue include: Engine stalling Difficulty starting Loss of power during acceleration HPFP failures can lead to significant performance issues and may require costly repairs or replacements. Failure leads to drivability issues ranging from long cranking times and misfires to complete engine shutdown. 7 psi 2008 535i N54 rough idle Have a 2008 535i with the n54, brand new fuel system from the rail back (high pressure, low pressure, sensors). If I accelerate for Your N54's persistent misfires, long cranks, or sudden power loss likely signal a failing low-pressure fuel pump (LPFP). From a tuning perspective with an aftermarket EC Mar 31, 2025 · What Causes HPFP Failures? Several factors contribute to high-pressure fuel pump failures in the N54: Design Flaws: Early N54 models contained faulty pumps although some replacement devices also failed prematurely. I am thinking its the HPFP. What should fuel rail pressure be at idle? - Page 2All times are GMT -5. fuel trims near 0% under moderate throttle. When Apr 19, 2019 · The Most Common N55 Fueling IssueAll times are GMT -5. Next day I have problems with leaving mine garage- when engine was cold is stop working 3 times (non stable idle RPM). For example, KF_PRAIL_H is the external map for rail pressure target and ip_sup_hom is the internal (Continental) rail pressure target that isn't used. Under Aug 6, 2019 · n54 rough idle All times are GMT -5. us My Yahoo! The BMW 335i's high-pressure fuel pump (HPFP) is a critical but frequently problematic component, particularly in N54 and early N55 engine models. However, despite its impressive capabilities, the N54 is notorious for common issues like fuel injector troubles, high-pressure fuel pump failures, persistent oil leaks, and cooling In this entry, I will explain the concept of HPFP pressure maintenance. The waste gates have started to rattle (500miles after install), and based on a few google searches, ive found out that boost related issues may result in this occurring. What is the HPFP problem with BMW? A failing or failed high-pressure fuel pump causes a limited flow of gases to the engine block. Sensor seems to be about $40, and the sensor/line $180. The car feels great and I don't understand how it could function without the LPFP. If I accelerate for Jun 10, 2025 · Fuel injectors are the lifeblood of any engine, and in the N54, they can be a real pain point. Aug 9, 2010 · Fuel pump, injector and yes give the reset throttle adaption a try, given your replacement. It is an n54 335 Appreciate 0 Tweet The N54 high pressure fuel pump (HPFP) is a critical, yet notoriously failure-prone component in BMW's acclaimed twin-turbocharged 3. Under load at with 50ish% pedal (according to Autel scanner) I’m reading 2,300+ psi at the rail. While the BMW N54 is considered one of BMW’s most modifiable and power-capable turbocharged engines, it does come with its pearly share of problems. But it appears your pressures are fine based on the Aug 3, 2020 · As far as the fuel pressure, I wouldn't worry about it too much yet. But unless you have a leaking injector (which should trigger mixture codes first) it won't affect crank time or idle quality. General things we look at when checking logs: 1) For absolute maps (all E series, F series maps > 2) is boost close to boost Discussion forum about issues with fuel rail pressure levels, high-pressure fuel pump (HPFP), and possible software glitches in BMW E90 vehicles. I crack open a fuel line and there's nothing coming out. The N54's low pressure fuel pump (LPFP) is a critical component responsible for delivering fuel from the tank to the high-pressure pump at the engine. N54 - MAP sensor gunked up?All times are GMT -5. My lpfp is def bad? I do get 29DC - Cylinder injection cutout at WOT and 2A2D - fuel low-pressure system, fuel pressure. The BMW N54 engine's high-pressure fuel pump (HPFP) is a well-known weak point frequently requiring replacement due to internal wear or failure, leading to symptoms like hard starting, loss of power, engine stalling, and misfire codes. 1 Step 1 – What is the mechanical configuration of the vehicle? 2. 3 Accesstuner Program shortcuts: 4 Table Descriptions and Tuning Tips 5 Boost Control Tables 6 Camshaft 7 Fuel « Previous Thread Next Thread » Fuel Mode 22 and Rail Pressure Spike at Idle Oct 7, 2024 · Low Fuel Rail Pressure - 2008 335i N55All times are GMT -5. UPDATE almost fixedtwitter Facebook Digg Google StumbleUpon del. The time now is . From what I've observed on my own car, sometimes, presumably when the fuel system is unable to maintain its target, it will go into a sort of "failsafe" mode where it disables the closed loop correction and runs a static 55% duty cycle at lower loads, and 100% at WOT. Failures manifest as rough idling, power loss, long cranking times, engine stalling, and warning lights. Never thought I would have to post on forums for help but here I am. I pulled the codes: 2DC3 - monitoring, terminal 15 2DED - power Sep 13, 2025 · Figure 3 In turbocharged models (N54 engine), the fuel under system pressure is further pressurized by a mechanically driven pump to pressures as high as 200 bar (2,900 psi) before being routed to the fuel injectors (green arrow). Alright so I'm still having some fuel troubles. Rough cold start 2. Apr 10, 2024 · « Previous Thread Next Thread » Bad fuel rail pressure sensor? My e93 335i N54 was running correctly for a total of three days until it decided it was time for the fuel system to fail again. to work, when I Sep 13, 2025 · Figure 3 In turbocharged models (N54 engine), the fuel under system pressure is further pressurized by a mechanically driven pump to pressures as high as 200 bar (2,900 psi) before being routed to the fuel injectors (green arrow). Recognizing symptoms early and understanding replacement options are essential for m N54 Help! Problems with turbos, HPFP, injectors? VERY detailed question The N54 engine's high-pressure fuel pump (HPFP) is arguably its most critical weak point, and proactive replacement is often necessary rather than optional. Last time I went through the ols, I haven't found any external maps for low pressure, but that wasn't my focus Sep 9, 2015 · What is a good/safe rail pressure for our engines when WOT? Or perhaps a minimum rail pressure below which we should be concerned about fuel system limits? For example, for the low pressure fuel pump it seems like above 50 psi is the acceptable lower limit. Is that normal? I thought the system was supposed to hold pressure for the next start. Feels like misfires when under mild acceleration. May 29, 2021 · I don't have, and have NEVER worked on, an N54, but my impression is that the Low Pressure Fuel Sensor at the engine sends the signal to your DME, and the value you see displayed on your Scan Tool is computed from the signal as received by the DME. (do it right, otherwise you idle will be all over the place, it should at least be in the state as before your throttle body replacement) You will most often not get a code when fuel issues causing an instable idle. Jul 18, 2025 · High-Pressure Fuel Pump (HPFP) Failures: One of the most notorious issues with the N54 is the failure of the HPFP. 20-30%, and often triggering 29E0. It runs very rough misfiring, I give it gas and it will drop some to 580 psi then up to 800 psi back to 600 psi. Feb 27, 2023 · N54 fuel pump connector melted. In this article, we’ll explore common BMW N54 engine problems in depth, from high-pressure fuel pump failures to wastegate concerns, providing owners with a comprehensive guide to understanding and addressing these issues. Causes Carbon buildup on injectors due to poor fuel quality Wear and tear from high-pressure operation Electrical issues affecting injector operation Solutions Regularly clean injectors Dec 24, 2014 · at idle and cruise my LTFTs are massively positive. so Customer: 2007 N54 335i --was starting, but surging at idle and no throttle response, no start at all now. eabixbbjfzadvusrlwnprnqwpsieljladqyyfmkkijprzyfjbkgjywqtqnjhkgnyjqmoofxgxxign