N47 long cranks and injector sounds

laurentium.ionescu · 11-04-2023, 09:12 AM

Hi,

I already made a post about my problem which I thought was solved but it turns out it isn't.

F30, 320D, 2012, N47D20C
There are 3 engine starting possibilities:
1. I let the engine crank for long (5-10 seconds) and it starts and runs.
2. I crank 2,3 or 4 times for like 2 or 3 seconds and the car either starts and runs fine, either starts, dies and after cranking again it runs fine.
3. Car immediately starts then dies and I crank again, engine starts and runs fine.

In all of these 3 cases between 1000
RPM - 1600 RPM there's a weird injector noise, it sounds like a tractor; after 1600 RPM engine sounds normal, there's no power loss at all or sudden stall.

Error code stored:
Quantity control valve, activation: Short circuit to ground(earth)

What I've tried:
Pump from the reservoir checked
Fuel lines checked
HPFP replaced, regulator included (it worked fine for around 5000 km then problem came back)
Temperature sensor right before HPFP replaced
Rail pressure regulator replaced (it worked fine for around 700 km, then problem came back)
Injectors checked

Please help me with any ideas, I run out of them and my mechanic too.

Eddamoo · 11-04-2023, 06:36 PM

Um, going out on a limb here but you have a fuelling problem and the fuel quantity control valve is shorted. Have you checked the wiring and replaced the valve?

The valve is designed to bypass fuel from the LPFP back to the tank on low fuel demand from the HPFP. The fact it's short means it's probably not allowing fuel to flow to the HPFP and just dumping fuel straight back into the fuel tank?

These things may fail safe, meaning unplugging it could cause the valve to stay closed and keep the fuel flowing. This will cause more wear in the LPFP however but may be worth checking?

laurentium.ionescu · 11-05-2023, 01:54 AM

Both of the regulators were replaced, the one from HPFP and the one from the rail.Tommorow I'll go to another BMW specialist to check my wires altough after some more research I don't think it's the case.

I don't think it's related to fuel itself going back to tge tank because this problem does not occur on first start only, it can happen all day no matter how many engine startups it has..

A few months ago when the problem occured I did this, I unplugged HPFP connector and the car seemed to start fine everytime so I thought this is the problem. I replaced the HPFP regulator than the problem occured again, I changed the HPFP and the regulator again (it came with it preinstalled) and it worked around 5000 km then problem occured again, I then replaced the rail pressure regulator with one known as good (used), it worked around 700 km so I ordered a new one (geniune) but it's not working.

After some more research I have three more leads:
The pump under the driver seat
Wires (less probably)
ECU itself (because sometimes it starts just fine)

I'll keep you updated.

11-04-2023, 09:12 AM	#1
laurentium.ionescu New Member 0 Rep 8 Posts Drives: BMW F30 2012 Join Date: May 2023 Location: Romania iTrader: (0)	N47 long cranks and injector sounds Hi, I already made a post about my problem which I thought was solved but it turns out it isn't. F30, 320D, 2012, N47D20C There are 3 engine starting possibilities: 1. I let the engine crank for long (5-10 seconds) and it starts and runs. 2. I crank 2,3 or 4 times for like 2 or 3 seconds and the car either starts and runs fine, either starts, dies and after cranking again it runs fine. 3. Car immediately starts then dies and I crank again, engine starts and runs fine. In all of these 3 cases between 1000 RPM - 1600 RPM there's a weird injector noise, it sounds like a tractor; after 1600 RPM engine sounds normal, there's no power loss at all or sudden stall. Error code stored: Quantity control valve, activation: Short circuit to ground(earth) What I've tried: Pump from the reservoir checked Fuel lines checked HPFP replaced, regulator included *(it worked fine for around 5000 km then problem came back)* Temperature sensor right before HPFP replaced Rail pressure regulator replaced (it worked fine for around 700 km, then problem came back) Injectors checked Please help me with any ideas, I run out of them and my mechanic too.
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11-04-2023, 06:36 PM	#2
Eddamoo Captain 394 Rep 816 Posts Drives: BMW 430dX Join Date: Apr 2018 Location: Sheffield, England iTrader: (0)	Um, going out on a limb here but you have a fuelling problem and the fuel quantity control valve is shorted. Have you checked the wiring and replaced the valve? The valve is designed to bypass fuel from the LPFP back to the tank on low fuel demand from the HPFP. The fact it's short means it's probably not allowing fuel to flow to the HPFP and just dumping fuel straight back into the fuel tank? These things may fail safe, meaning unplugging it could cause the valve to stay closed and keep the fuel flowing. This will cause more wear in the LPFP however but may be worth checking?
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11-05-2023, 01:54 AM	#3
laurentium.ionescu New Member 0 Rep 8 Posts Drives: BMW F30 2012 Join Date: May 2023 Location: Romania iTrader: (0)	Both of the regulators were replaced, the one from HPFP and the one from the rail.Tommorow I'll go to another BMW specialist to check my wires altough after some more research I don't think it's the case. I don't think it's related to fuel itself going back to tge tank because this problem does not occur on first start only, it can happen all day no matter how many engine startups it has.. A few months ago when the problem occured I did this, I unplugged HPFP connector and the car seemed to start fine everytime so I thought this is the problem. I replaced the HPFP regulator than the problem occured again, I changed the HPFP and the regulator again (it came with it preinstalled) and it worked around 5000 km then problem occured again, I then replaced the rail pressure regulator with one known as good (used), it worked around 700 km so I ordered a new one (geniune) but it's not working. After some more research I have three more leads: The pump under the driver seat Wires (less probably) ECU itself (because sometimes it starts just fine) I'll keep you updated.
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