Need a bit of fanatic help here...

[OppositeLockMT]

Okay so a bit of background info: I have been experiencing fuel pump issues, the car (E46 328i) was returning horrible fuel consumption numbers: 15l/100kms. It hit rock bottom when the car would cut out in traffic and only start up after 2minutes or so - car would run fine but the cycle would only continue after driving a few Ks. Realised it was a faulty fuel pump and had that changed immediately.

Currently: The car is running perfectly now and averaging 11.2l/100kms, which is pretty impressive imo. However, the car is developing some sort of alter-ego or suffering from a bout of bi-polar as it's now experiencing starting issues: sometimes when i try to start the car it will crank, start up, sputter, cough and then die out, when i try to start the car up right after it starts without any issue :flyfun:. The car runs fine when it's started up, it's just getting it started that's a problem (sometimes - more often when the car has been sitting for a while).

Note: When putting the key in accessory mode (position 2) there is some sort of peculiar buzzing/humming noise that seems to be coming from the pump - the noise only lasts about 7 seconds, I never had this before and I'm wondering whether this could be the cause?

Will get the codes read ASAP but would also like some fanatic insight!

 

[Sankekur]

The buzzing when you turn the key is normal....or at least the fuel pump should run for a couple of seconds after turning the key......if it is buzzing and it wasn't before then it might be that the pump is on its way out, but it should also be said a buzzing pump doesn't mean its failing, it can buzz and last years.
Best would be to hook up a pressure gauge to the fuel line and monitor the fuel pressure.

 

[OppositeLockMT]

The buzzing when you turn the key is normal....or at least the fuel pump should run for a couple of seconds after turning the key......if it is buzzing and it wasn't before then it might be that the pump is on its way out, but it should also be said a buzzing pump doesn't mean its failing, it can buzz and last years.
Best would be to hook up a pressure gauge to the fuel line and monitor the fuel pressure.

Thanks,

I've been waiting for the buzzing to stop thinking that it would help up until recently, waited for the buzzing to cease before I started the car but it still coughed and sputtered to life.

 

[Sankekur]

Yea it primes the pump or something, not really sure why as some BMW's do it (like e46's) where other (like e34's) don't.

Personally I normally just wait for it to stop before starting......I am weird

Now might also be a good time to check/replace your petrol filter.

 

[Kish2604]

Hopefully some other members can help with some pictures but I believe there is supposed to be a check valve that supposed to maintain the pressure in the fuel line, perhaps this is we're he fault lies? Perhaps try cycling the key more than once before starting to make sure the system is fully primed? I would also believe that the prime cycle is controlled by the relay and is time dependent and not fuel pressure dependent... Lastly, could one of the pipes be loose from the fuel pump replacement? Fuel filter should ave been changed a well en the pump was changed.

Let us know what you find..

 

[OppositeLockMT]

Hopefully some other members can help with some pictures but I believe there is supposed to be a check valve that supposed to maintain the pressure in the fuel line, perhaps this is we're he fault lies? Perhaps try cycling the key more than once before starting to make sure the system is fully primed? I would also believe that the prime cycle is controlled by the relay and is time dependent and not fuel pressure dependent... Lastly, could one of the pipes be loose from the fuel pump replacement? Fuel filter should ave been changed a well en the pump was changed.

Let us know what you find..

I will try cycling the key more than once before starting, i found that waiting for the pump to prime helped a bit. Have never thought of waiting for the pump to get sorted up until now, used to just get in and go. I don't understand why exactly this happens with the E46, we have an E60 530i and I've never heard that buzzing noise :argh:

Will have my mechanic look over the pipes, I suspect it's a clogged filter.

This is exactly what's happening, EXACTLY (this isn't me :fencelook:

[video=youtube]

 

[Ralf*]

I had similar problems on my E39 530d a few years ago, and google search led me to these forums, which is when I signed up.

The advise given me was the crank and/or cam sensor.

the cam sensor was so easy to replace as it sits right on the top in front, so that was my first call, and viola...its starts every time since then

possibly ??

 

[Kish2604]

Cool,let us know what u dig up..

 

[Baron]

My E46 also has the fuel pump whine when you first turn the key, but it only lasts for about 1.5 seconds, is there not maybe a leak somewhere that it's not building up enough pressure or building up pressure too slowly?

 

[OppositeLockMT]

My E46 also has the fuel pump whine when you first turn the key, but it only lasts for about 1.5 seconds, is there not maybe a leak somewhere that it's not building up enough pressure or building up pressure too slowly?

That's a possibility. Haven't gotten the codes read yet but I think it's one of four things: Fuel Filter, Crankshaft Sensor, Camshaft Sensor, or simply a loose hose that's creating a pressure leak

 

[firaz]

http://www.bmwfanatics.co.za/showthread.php?tid=6599

 

[Iceman007]

maybe a injector leaking over night:fencelook:

 

[OppositeLockMT]

Bump

I managed to sort out the starting issue after my initial post - replaced the fuel pressure valve. This morning I went out to the car just to get it started, put the key in the accessory position and waited for the buzzing noise from the fuel pump to stop like I usually do (sounded a bit faint this time around), I went on to try and start the car and it just cranked for about 7 seconds, I switched it off and tried it out for the second time and it started up like nothing happened.

I tried switching the car on again after leaving it for about 6 hours - give or take. This time it just coughed and sputtered to life on the first try then stalled out, tried starting it up again and surprise surprise...started up as usual.

I replaced the pump recently so I double that's the problem.

Is it a:
- Leaking Injector
- Another faulty pressure valve
- Clogged filter
- Spark Plugs

I have absolutely no idea what's going on with this car! :bangdesk:

 

[Pfw28]

Step 1 would be to establish whether it's flooding or starved of fuel. Need a "sniffer" at the exhaust when you start up, smell petrol or not. If it's flooded, leaky injectors seems the most likely, if no smell of petrol, then look into pipes etc on the supply side. Good luck. :fencelook: