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Hi there, I need your expert opinion. I've got mini cooper R56 base model no S, n12 engine. The problem start yesterday when the engine cut off itself as I drove without any errors on the dashboard! Not able to start since then! Towed to home. Scan it for errors and no any errors stored! The LPFP not priming in ignition on! Get 10.9 volts to the fuel pump while cranking and jumps to 12 when starter stops after 5 sec. before returning to zero. Fuel pressure reaches 50 psi over 30 seconds of cranking and drops to zero when stop cranking. Engine never starts even upon reaching 50 psi. I am really confused. Any idea what could be the fault? Cheers!
This is an easy one my friend, but I do have some bad news too.
It appears your fuel pressure regulator has failed in the open position. The pump runs, but all pressure dumps when you stop cranking because it is flowing through the open regulator back to the tank. With the pressure loss back to the tank, there isn't enough gas to support combustion. "System fuel pressure is created by the in-tank fuel pump, and MAINTAINED by the fuel pressure regulator."
The bad news is the regulator is integrated with the fuel filter assembly and right-side fuel level sender inside the fuel tank instead of being on the fuel rail where it should be.
This is an easy one my friend, but I do have some bad news too.
It appears your fuel pressure regulator has failed in the open position. The pump runs, but all pressure dumps when you stop cranking because it is flowing through the open regulator back to the tank. With the pressure loss back to the tank, there isn't enough gas to support combustion. "System fuel pressure is created by the in-tank fuel pump, and MAINTAINED by the fuel pressure regulator."
The bad news is the regulator is integrated with the fuel filter assembly and right-side fuel level sender inside the fuel tank instead of being on the fuel rail where it should be.
Tank you so much for your reply! Can I do any troubleshoot on this presure regulator or needs replacing if its possible. And does faulty presure regulator can cause the car to shut down as driving? Another thing that I found is the fuil pump not prime on ignition on! Checked the pump terminal for priming voltage on ignition on and no voltage present. It appear 5 sec after stop cranking only! How weird is that!
You already have performed a key part of the troublshooting; you know the fuel pump works (fuse, relay, pump etc) and you know the regulator doesn't (it won't maintain system pressure). The DME controls the fuel pump relay. The Bentley Manual doesn't go into the logic in the DME only that that DME provides the ground circuit to the fuel pump relay during starting and "the fuel pump runs as long as the ignition switch is in START position and continues to run once the engine starts." I know some cars will prime the fuel pump as soon as you turn the ignition to on, but according to Bentley ... not on the MINI. The pump appears to prime during start. In a normal system with a good fuel pressure regulator, there should be pressure in the fuel line all the time (maintained by the regulator), so no priming should be required. This is why the manual tells you to "release" the fuel pressure anytime you work on the fuel system. It's under pressure. Make sense? Oh! I forgot, the spec for fuel pressure is 72.5 PSI not 50. Since you don't have fuel leaking all over the ground, I'll bet the 22.5 PSI you're missing is due to the faulty regulator.
Yes you can do this yourself, but you will need some tools:
1. Bentley service manual (section 160)
2. BMW special tool 16 1 020 or equivalent (the "BMW" tool is expensive)
3. Absolutely! A faulty regulator means fuel flows directly from the fuel filter back into the tank; path of least resistance means the fuel would rather stay in the tank; this is also why you don't have any check engine light; the fuel pressure is not monitored by the DME. The reason they put the regulator in the tank is to eliminate the second fuel line from the fuel rail back to the tank for the return line.
"For quick restarts and to avoid vapor lock when the engine is hot, the fuel injection system retains fuel pressure after the engine is shut off. This residual pressure is primarily maintained by the fuel pressure regulator and a check valve at the fuel pump outlet."
When you say the fuel pump assembly with filter and regulator all on the right side, do you mean passenger side? I noticed that there is an access plate on the left side(driver side). What is the access plate used for?
BMW/MINI like things complicated; so instead of one fuel pump, filter, level sensor assembly (like in most cars), You have two access panels, one on the left (perspective of the driver as seated in the car), and one on the right (or passenger side). The pump is under the panel on the left, the one on the right is the fuel filter, level sensor, and regulator. You have to remove the pump before you remove the filter/level sensor assy; there are hoses that connect the two together.
Please order your Bentley service manual if you don't have one.
Ladies and Gents of the esteemed forum. I’d like to submit my own crank, no start case for verification on my thought process and any corrections or advice you may all have. Scroll down to the portion in between the asterisks for the main idea behind the post.
Vehicle: 2007 MCS: R56N14
I have 2 possibly likely causes, though this doesn’t really rule out anything. One, I discovered a skunk had sought refuge one day behind the air intake. After waterboarding it to urge it elsewhere, it peeked out and rested its paws on the air intake housing as if it a child peering over a table and resting its arms on it. Cute. Anyway, possible effects may have been wiring issues or tears in hoses that I have yet to find. Time of incident: About 2.5 months before my vehicle shutting down at a traffic light after 2 hours at highway speeds. Hasn’t started since.
2nd possible cause: Valero gas from TX. I only fueled here out of desperation in San Antonio, made a mental note to add a fuel additive on the side, and promptly forgot to add said fuel additive. 2 days and 2/3 of the fuel tank later, car shuts down and never starts again. I’ve always strongly suspected the odds of Valero gas to have bad gas to be high, thus avoiding them.
I’ve had my fuel pump replaced before, after a case of bad Costco gas. This was brought to my attention about a month after my car wouldn’t start and shipped off to the dealership by Costco itself. They promptly reimbursed me, at least the deductible for my extended warranty at the time. My own expenses were much more for taking it to the dealership and them refusing to work on the problem until they took care of the brakes first…..Anyway, this was 6 years and 25K miles before this newest incident. It’s been 9 years and same number of miles as of today.
I’ve reattempted to resuscitate my vehicle with renewed vigor and have armed myself with new weapons to tackle this problem, and possibly become an accidental BMW tech. I now have ISTA-through K+DCAN OBD access.
Along with a new battery, I’ve replaced the sole camshaft position sensor (intake), mainly because a certain someone wouldn’t stop harping about and had to get him off my case. I now have a 2982 camshaft sensor fault code for my efforts. I’ve backprobed the camshaft sensor and can confirm that the Hall effect works when bringing it near metal. The signal wire is currently about 11.7 V, and has a 0.63 voltage differential with the battery positive. When cranking, the voltage drops to about 10.7 Volts, and jumps back up to 11.4~11.5 and slowly climbed up when I had the battery on a trickle charger. I can’t get a 0 Voltage reading out of the camshaft sensor when cranking, aside from possibly 1 time when I was attempting to quickly abort the crank, but I don’t wish to repeat that considering how my starter was starting to sound from the abuse. I’m trying to avoid manually rotating the crankshaft for now to check, so I think I’ll leave that until after my car starts.
On to the 4 main causes of crank/no start: Spark/Fuel/Compression/Air
Spark: All spark plugs and coils are working. The plugs are all gapped to .032 in, and seem relatively with some carbon buildup. The plugs fire right when the coils do, though the coils activate about 3-5 seconds after the cranking starts. This may mean I have to change the coils soon enough but it doesn’t seem to be my no start problem. I didn’t have a lab scope to look at the waveform. I used the spark plug test light and connected it between the coil and spark plug.
Air: I’ve attempted to start with the MAF sensor disconnected. No luck. No visible leaks in air hoses.
Compression: Avoided for now, but I believe it shouldn’t be an issue to start the car. I do know I should walnut blast those valves ASAP. Also, have any of you ever tried to crank the car with only one coil connected? It lacks the rhythm you get accustomed to and seems to be a continuous sound that just sounds plain wrong for a car. I hypothesize the ignition inside the cylinders contributes to that rhythmic cranking pulse.
Fuel: Fuel pump primes after cranking, not when key is in ignition, though mkov608 posted that MINI doesn’t prime when you open the door or put your key in the ignition. The pump will also prime after about a half hour while the key has been in the ignition. I don’t know if it does this when it’s not in the ignition.
I’ve fiddled with the filter in the past (car hasn’t started in 3 years come Thanksgiving), and I believe I may have dismissed it as a problem when I disconnected the fuel line from the filter. In hindsight, that may have been the feed line from the pump to the filter, and not the outlet hose from the filter to the rest of the car. What is the hose that connects at the top of the filter, inlet or outlet?
I swapped out my JBE with a used JBE last September/October just in case I had a fuel relay problem, though I don’t think that was the issue. Thought I should with the other issues I was having with my car before, such as no AC (may actually just be the yellow connector near the compressor). I’m getting a fault code now with the right fuel level sensor along with others that might have to do with damaged connector pins. I’ll have to take a look when I have space to open it up again, but again, I’m focusing on the car starting for now and I don’t think any of these have to do with that. The right fuel sensor also presents a fault code in KOMBI (instrumentation panel). I still have my old one to swap back and check now that I have ISTA.
I know now that a bad fuel filter adds a lot of resistance to the pump, so I’m waiting on a new one to come in and will be replacing it. Even have a proper tool for the spanner, which should make easy work of it, and should allow me to tighten it to torque specs. It’s possible my LP fuel pump has been overworking itself, but I have yet to test the voltage and amp readings on it.
Here is where my current diagnostic deductions have my focus. I have the readings from the rail pressure sensor from the high pressure fuel system. The actual value will reach 1.15 MPa when cranking, which is 11.5 bar. It is my understanding that the HPFP essentially multiplies the rail pressure from the low pressure feed line by a factor of 10. Any more than that seems unfavorable and may be signs of problems with your unit or my shorten the lifespan of it. Now, I believe the HPFP is driven mechanically by the camshaft, or some other shaft in there, and not electrically, so it clearly won’t be operating at proper efficiency when merely cranking the car, as the RPM needle barely moves then (I’d say 100-200 rpms would be likely but I’d have to double check and eyeball it). At idle, the actual pressure sensor should be reading 5 MPa=50 bar, which should be the same value as your setpoint value. My setpoint value is currently 0 MPa. I don’t think that is going to change until the car engine starts and the sensor gets a reading after about a second after that.
************************************************** *************************************************
So, for all the TLDR.. Currently my rail pressure sensor has the fuel in the rail at 1.15 MPa=11.5 bar when cranking. It seems it maintains a reading of 11 bar at all times, no matter what. This is the high pressure fuel system reading. With the low rpms of the engine when cranking, I don’t know how much more it has pressurized the fuel. I know idle RPMs should be ~600-1000 RPM. If at 100-200 RPM, it’s only increased it by a factor of 2, my LP fuel pressure is in acceptable ranges… if it’s 3 or more, it’s likely my fuel pressure is low. I’m hoping this is my problem, caused by a bad filter and to a less extent, an exhausted LP pump motor. I’d like to tap into the LP fuel line, but lacking a convenient Schrader valve port, I’m having trouble finding a good place to tap into. Pelican Parts, has me following the feed line from the HPFP down the rabbit hole. Even after removing the air filter housing, it’s inaccessible from the top. It seems I might have to tap into from underneath the car, which is posing an issue currently, but I will attempt it somehow tomorrow. (I removed the F43 fuel fuse from the JBE to let the pressure fall overnight). According to ISTA, I should tap into the feed line near the front bar stabilizer. I think this is the same spot Pelican Parts points to, though it’s hard to tell. Either way, it seems underneath is the way to go unless anyone has other ideas.
is my reasoning sound? Is this likely the source of my problem? Alternatively, it could be a bad HPFP, but I’ve heard the car will at least start somewhat and proceed to stall out in that case. Mine never gets the engine going. I think spraying the hoses to see if ignition will result from the flammable spray did nothing. I can’t remember properly, but we may have sprayed inside the spark plugs in the past, though that likely wouldn’t work with the time needed to reinstall the plug again. ************************************************** ***********************************************
Sorry for all the extraneous information. I don’t think I could discuss my problem concisely, though I should. I probably need some sort of therapy for my R56 woes and dealerships and specialty shops. Avoid San Antonio Euro. They caused me tons of grief in 2014, always holding onto the car for excessive periods of time; never fixing the problem, and always adding more problems that I didn’t have before. I obtained an AC problem, a bad clutch, and possible a faulty FRM module, or at least I seem to have plenty of fault codes that are connected to the FRM module. There are other problems I’m glossing over, but I did not have one good experience from them. They kept my car a total of 9 out of the 11 first months from just 3 visits, the last visit being 6 continuous months I was without a vehicle. Thousands of dollars in repairs were charged, probably closer to the 10K mark. Luckily I had an extended warranty that saved me with a 200 deductible each time, which has since expired (2016?). I believe I spent about 2K of my own money. You can see how I preferred to tackle the problem myself, rather than pour money down the drain when this new problem happened at the end of 2018.
Sensor readings from fuel rail pressure of high pressure fuel system.
Last edited by avarath; 07-22-2021 at 10:28 PM.
Reason: to add a footnote and attachment
Pics of my squatter. Don’t think he was there for more than a day or 2. This was 2 months prior to my crank no start issue after car silently stalled out at a light without me noticing with the radio on.
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Adding my situation to this thread, my initial symptoms were practically identical to OP's, so I replaced the filter housing and sending unit assembly. After I got it in however, I wasnt getting any fuel pressure anywhere. It now has a new fuel pump in as well, but still no pressure anywhere. I've checked everything I can according to the Bentley manual, and everything seems to check out as far as I can tell, so now I'm just at a loss. Any help would be much appreciated.
Adding my situation to this thread, my initial symptoms were practically identical to OP's, so I replaced the filter housing and sending unit assembly. After I got it in however, I wasnt getting any fuel pressure anywhere. It now has a new fuel pump in as well, but still no pressure anywhere. I've checked everything I can according to the Bentley manual, and everything seems to check out as far as I can tell, so now I'm just at a loss. Any help would be much appreciated.
BMW/MINI like things complicated; so instead of one fuel pump, filter, level sensor assembly (like in most cars), You have two access panels, one on the left (perspective of the driver as seated in the car), and one on the right (or passenger side). The pump is under the panel on the left, the one on the right is the fuel filter, level sensor, and regulator. You have to remove the pump before you remove the filter/level sensor assy; there are hoses that connect the two together.
Please order your Bentley service manual if you don't have one.
What year and model does this refer to? Mine is a 2011 R56 with the N18 engine.
Pelican parts says the pump should reach 72 psi and allow the fuel system to sit under pressure for 15 minutes. Pressure should drop no more than 0.5 bar in that time period.
Mine reaches 72 psi but doesn't maintain pressure after the engine is turned off...it drops immediately to zero.
So should I replace the filter/regulator assembly in the right/passenger fuel tank??
What year and model does this refer to? Mine is a 2011 R56 with the N18 engine.
Pelican parts says the pump should reach 72 psi and allow the fuel system to sit under pressure for 15 minutes. Pressure should drop no more than 0.5 bar in that time period.
Mine reaches 72 psi but doesn't maintain pressure after the engine is turned off...it drops immediately to zero.
So should I replace the filter/regulator assembly in the right/passenger fuel tank??
My 2012 N18 had the issue of not maintaining pressure at the High Pressure pump turned out to be the regulator on the fuel filter side not maintaining pressure, no pressure even when I disconnected the fuel line which should be under constant pressure which is maintained by the regulator.
My 2012 N18 had the issue of not maintaining pressure at the High Pressure pump turned out to be the regulator on the fuel filter side not maintaining pressure, no pressure even when I disconnected the fuel line which should be under constant pressure which is maintained by the regulator.
Is the regulator located in the passenger side fuel tank with the filter or on the drivers side with the low pressure fuel pump?
Is there a part number?
I was getting HPFP codes of low pressure cold start, and low HPFP pressure.
I changed the LPFP and the HPFP.
Now I get a code that says fuel pressure too high.
Last edited by BobbyS; 10-17-2023 at 04:52 PM.
Reason: more info
[QUOTE=BobbyS;4663512]Is the regulator located in the passenger side fuel tank with the filter or on the drivers side with the low pressure fuel pump?
Is there a part number?
I was getting HPFP codes of low pressure cold start, and low HPFP pressure.
I changed the LPFP and the HPFP.
Now I get a code that says fuel pressure too high.[/QUOTE
Regulator and fuel filter is passenger side part# 16112755084.
My 2012 N18 had the issue of not maintaining pressure at the High Pressure pump turned out to be the regulator on the fuel filter side not maintaining pressure, no pressure even when I disconnected the fuel line which should be under constant pressure which is maintained by the regulator.
When you disconnected the fuel line....with the car off, correct?
My 2012 N18 had the issue of not maintaining pressure at the High Pressure pump turned out to be the regulator on the fuel filter side not maintaining pressure, no pressure even when I disconnected the fuel line which should be under constant pressure which is maintained by the regulator.
I replaced the fuel filter assembly with regulator and the pressure stays up after the key off....fuel sprays when I disconnect the line after shutdown. It didnt do that before so I think that's solved.
In the morning and spits and sputters for a minute or so on cold start.
And.....Still showing too high fuel pressure code on hpfp.
I also intermittently have various CAS module codes especially when it's hot outside. Could the CAS problems be the source of my cold start issues? What tells the lpfp to run?
Vehicle: 2007 MCS: R56N14 ************************************************** *************************************************
So, for all the TLDR.. Currently my rail pressure sensor has the fuel in the rail at 1.15 MPa=11.5 bar when cranking. It seems it maintains a reading of 11 bar at all times, no matter what. This is the high pressure fuel system reading. With the low rpms of the engine when cranking, I don’t know how much more it has pressurized the fuel. I know idle RPMs should be ~600-1000 RPM. If at 100-200 RPM, it’s only increased it by a factor of 2, my LP fuel pressure is in acceptable ranges… if it’s 3 or more, it’s likely my fuel pressure is low. I’m hoping this is my problem, caused by a bad filter and to a less extent, an exhausted LP pump motor. I’d like to tap into the LP fuel line, but lacking a convenient Schrader valve port, I’m having trouble finding a good place to tap into. Pelican Parts, has me following the feed line from the HPFP down the rabbit hole. Even after removing the air filter housing, it’s inaccessible from the top. It seems I might have to tap into from underneath the car, which is posing an issue currently, but I will attempt it somehow tomorrow. (I removed the F43 fuel fuse from the JBE to let the pressure fall overnight). According to ISTA, I should tap into the feed line near the front bar stabilizer. I think this is the same spot Pelican Parts points to, though it’s hard to tell. Either way, it seems underneath is the way to go unless anyone has other ideas.
is my reasoning sound? Is this likely the source of my problem? Alternatively, it could be a bad HPFP, but I’ve heard the car will at least start somewhat and proceed to stall out in that case. Mine never gets the engine going. I think spraying the hoses to see if ignition will result from the flammable spray did nothing. I can’t remember properly, but we may have sprayed inside the spark plugs in the past, though that likely wouldn’t work with the time needed to reinstall the plug again. ************************************************** *********************************************** .
I just posted on how to manually test LPFP but if you have a scanner you can just put the key on engine off and it will read that pressure for you and save you the aggravation. Should be 72.5 psi.
Did you check your grounds? 4 of them in the engine bay. I just posted on that. If they are bad you will have many issues.
Did you check for wires that were likely chewed by the skunk?
Why is your engine bay all wet in the pic with the skunk? Did you power wash it? IF so...ya better start pulling all the connectors and spraying with electronic connector cleaner.
04-04-2021, 03:38 AM
