Diesel pump issues

[Vaughan]

Hi all

So lately my E46 2002 FL 320d doesn't like starting sometimes but I have noticed that the pre-start priming noise that I used to hear coming from the back seat has vanished. Does anyone know what I should look for like a pre-ignition relay or maybe a valve or do you think it's just the pump that busy going ? Any suggestions would be much appreciated.

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[Nikhil]

Check the codes you will get a low rail pressure fault

 

[Nikhil]

Whats your mileage aswell,?

 

[Vaughan]

Whats your mileage aswell,?

241028km

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Check the codes you will get a low rail pressure fault

Will do it as soon as I can get to a machine thanks for the tip though.

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[Nikhil]

Its most likely the lpfp under the car thats shot. Speak to Gert from obd works for a Meyle unit:coolShake: bmw is 6k for a new one and the doe pump from autozone is annoyingly loud

 

[Vaughan]

Its most likely the lpfp under the car thats shot. Speak to Gert from obd works for a Meyle unit:coolShake: bmw is 6k for a new one and the doe pump from autozone is annoyingly loud

Not to sound too stupid but what's a lpfp ?

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[Nikhil]

Its most likely the lpfp under the car thats shot. Speak to Gert from obd works for a Meyle unit:coolShake: bmw is 6k for a new one and the doe pump from autozone is annoyingly loud

Not to sound too stupid but what's a lpfp ?

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Low pressure fuel pump, might as well replace the fuel filter while in there. The pump in the tank is the lift pump and the 3rd pump is the high pressure fuel pump that sits in the engine bay

 

[GPGrobler]

Sheesh, 3 pumps for a Diesel, must cost a fortune when the fuel system decides to pack up! Well, anyways Autozone, Goldwagen and the like also stock the Bosch units at a whole lot less than BMW.

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Sheesh, 3 pumps for a Diesel, must cost a fortune when the fuel system decides to pack up! Well, anyways Autozone, Goldwagen and the like also stock the Bosch units at a whole lot less than BMW. However not sure whether the d uses Bosch or Meyle, maybe ask around a bit more and find out if BMW sells the Bosch units or not? If they do just buy the Bosch from Midas or whoever stocks them at about 60% less than BMW will charge you :idea:

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I suggest doing it soon though, a starter motor and the labour charged to exchange it is not cheap!

 

[Vaughan]

Its most likely the lpfp under the car thats shot. Speak to Gert from obd works for a Meyle unit:coolShake: bmw is 6k for a new one and the doe pump from autozone is annoyingly loud

I replaced the LPFP to no avail. It's now onto the next trial. I managed to get a replacement pump to test with (el cheapo) for 2k. I'll relay next

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[Nikhil]

damn :smashScreen: let us know the outcome

 

[Vaughan]

damn :smashScreen: let us know the outcome

OK so had a chat to BMW this morning and they seem to think that it's the relay. But they said not to replace it and just to check the soldering in the relay cause that car mainly does this "not starting" when it's cold ( like in the mornings currently it a battle)

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[S1NGH 911]

It could be a relay, does it battle to start intermittently or only over night?

 

[Vaughan]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

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[S1NGH 911]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

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I've seen a very similar issue but on an E90.

It was two relays that work in tandem which were the culprits.

One was located under the dashboard and the other in the engine bay if I'm not mistaken.

Managed to find the screen shot of it.

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[Vaughan]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

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I've seen a very similar issue but on an E90.

It was two relays that work in tandem which were the culprits.

One was located under the dashboard and the other in the engine bay if I'm not mistaken.

Managed to find the screen shot of it.

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i just replaced the one in the bonnet now to find that other one as the problem persists

 

[Vaughan]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

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I've seen a very similar issue but on an E90.

It was two relays that work in tandem which were the culprits.

One was located under the dashboard and the other in the engine bay if I'm not mistaken.

Managed to find the screen shot of it.

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Officially not the problem. Just put that second relay in and nada still no pre-diesel pump sounds and no starting

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[S1NGH 911]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

Sent from my SM-G900F using Tapatalk

I've seen a very similar issue but on an E90.

It was two relays that work in tandem which were the culprits.

One was located under the dashboard and the other in the engine bay if I'm not mistaken.

Managed to find the screen shot of it.

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Officially not the problem. Just put that second relay in and nada still no pre-diesel pump sounds and no starting

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Sorry buddy, I'm now stumped


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[Vaughan]

It could be a relay, does it battle to start intermittently or only over night?

Only when the car has stood for a while especially overnight

Sent from my SM-G900F using Tapatalk

I've seen a very similar issue but on an E90.

It was two relays that work in tandem which were the culprits.

One was located under the dashboard and the other in the engine bay if I'm not mistaken.

Managed to find the screen shot of it.

Sent from my iPhone using Tapatalk

Officially not the problem. Just put that second relay in and nada still no pre-diesel pump sounds and no starting

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Sorry buddy, I'm now stumped


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You and me both. And it's just getting worse with the not wanting to start

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[zippy320]

maybe a stupid question but did you check the fuse?

On my E46 , what had happened was , the internal low pressure pump failed, which in turn caused the fuel pump relay to fail ( the one that fits behind the cubby box ) I replaced the pump and relay and it started , I also checked both fuses .
There is a fuse in the cubby at the top and another in like a sort of black box with 6 fuses I think.

Im not sure if the diesel cars are the same as the petrol, but worth a try .
Do these cars have main relays? I know on the E30 that's one fuse that I always check.

Best to have it plugged into a PC for diagnoses as well . maybe also check with a test light if the fuel pump or pumps are getting power and narrow it down from there.

 

[Vaughan]

maybe a stupid question but did you check the fuse?

On my E46 , what had happened was , the internal low pressure pump failed, which in turn caused the fuel pump relay to fail ( the one that fits behind the cubby box ) I replaced the pump and relay and it started , I also checked both fuses .
There is a fuse in the cubby at the top and another in like a sort of black box with 6 fuses I think.

Im not sure if the diesel cars are the same as the petrol, but worth a try .
Do these cars have main relays? I know on the E30 that's one fuse that I always check.

Best to have it plugged into a PC for diagnoses as well . maybe also check with a test light if the fuel pump or pumps are getting power and narrow it down from there.

Well I been playing around for the last hour or so and the relays behind the cubbyhole are green,salmon,green and green, now all the wiring diagrams I can find with these are not really accurate. I replaced the supposed relay and nothing then started swapping the greens around and the second from the right was the last swapped and vwala the cars pre-priming just started work time after time. The only issue is I have either put the faulty relay into the hooter or the air pump. But will test further shortly

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maybe a stupid question but did you check the fuse?

On my E46 , what had happened was , the internal low pressure pump failed, which in turn caused the fuel pump relay to fail ( the one that fits behind the cubby box ) I replaced the pump and relay and it started , I also checked both fuses .
There is a fuse in the cubby at the top and another in like a sort of black box with 6 fuses I think.

Im not sure if the diesel cars are the same as the petrol, but worth a try .
Do these cars have main relays? I know on the E30 that's one fuse that I always check.

Best to have it plugged into a PC for diagnoses as well . maybe also check with a test light if the fuel pump or pumps are getting power and narrow it down from there.

Well I been playing around for the last hour or so and the relays behind the cubbyhole are green,salmon,green and green, now all the wiring diagrams I can find with these are not really accurate. I replaced the supposed relay and nothing then started swapping the greens around and the second from the right was the last swapped and vwala the cars pre-priming just started work time after time. The only issue is I have either put the faulty relay into the hooter or the air pump. But will test further shortly

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Got it fixed "well here's hoping" but there is still a faulty relay which I have stuck into the hooter for now. The car seems to prime every time for the last hour.

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