635csi '86, can you hear fuel pump?

"Dru Abrams" > wrote
> Can you actually hear the fuel pump running when ignition set to "on"
> position? I can't, and engine isn't getting fuel. Before deciding the
> problem is a bad in-tank fuel pump need to know if other owners can hear
> their fuel pumps running when car isn't running...

That seems normal - I could always hear the pump on my 530i (which
had similar FI to later 3.5L engines).

Floyd

Can you actually hear the fuel pump running when ignition set to "on"
position? I can't, and engine isn't getting fuel. Before deciding the
problem is a bad in-tank fuel pump need to know if other owners can hear
their fuel pumps running when car isn't running...

Thanks!
Dru

> > Can you actually hear the fuel pump running when ignition set to "on"
> > position? I can't, and engine isn't getting fuel. Before deciding the
> > problem is a bad in-tank fuel pump need to know if other owners can hear
> > their fuel pumps running when car isn't running...
>
> That seems normal - I could always hear the pump on my 530i (which
> had similar FI to later 3.5L engines).

Agreed.

Undo the rubber hose that comes from the bottom of the fuel pressure
regulator. Hold a (preferably glass) bottle under it and have someone
else run the engine briefly. You should get fuel.


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In article >,
Dru Abrams > wrote:
> Can you actually hear the fuel pump running when ignition set to "on"
> position? I can't, and engine isn't getting fuel. Before deciding the
> problem is a bad in-tank fuel pump need to know if other owners can hear
> their fuel pumps running when car isn't running...

I'm not sure about your car exactly, but on my 'other' car of about that
age - not a BMW - with EFI by Lucas but based on Bosch, the pump only
starts running when the starter circuit is energised, or the AFM flap
opened. It then latches on. The starter circuit also bypasses the pump
series resistor while in operation.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dru Abrams" > wrote in message
...
> Can you actually hear the fuel pump running when ignition set to "on"
> position? I can't, and engine isn't getting fuel. Before deciding the
> problem is a bad in-tank fuel pump need to know if other owners can hear
> their fuel pumps running when car isn't running...
>
> Thanks!
> Dru
>

My old 735i (same engine) used to leave an injector open or a one way valve
leaked, so if the car was left for a few days the fuel line was empty you
could hear the fuel pump for a few seconds (followed by little pulses until
it was happy) as it refilled the line. If you disconnect down stream of the
pump (at the fuel filter perhaps) then it should pump fuel when you switch
on the ignition.


Warning - do not smoke during this operation!

In article >,
R. Mark Clayton > wrote:
> My old 735i (same engine) used to leave an injector open or a one way
> valve leaked, so if the car was left for a few days the fuel line was
> empty you could hear the fuel pump for a few seconds (followed by
> little pulses until it was happy) as it refilled the line. If you
> disconnect down stream of the pump (at the fuel filter perhaps) then it
> should pump fuel when you switch on the ignition.

Fuel being present isn't the only thing - it must also be at the correct
pressure. IIRC, the most common reason for the line losing pressure
quickly is a worn fuel pump. If an injector or injectors were leaking this
would show up as a rich mixture and poor fuel consumption especially at
low throttle.

--
*Drugs may lead to nowhere, but at least it's the scenic route *

Dave Plowman London SW
To e-mail, change noise into sound.

Hey all.

Thanks for the info and help.

I had the car fixed today at Brownfeld Auto in Manhatten. They said
both pumps were dead. Replaced both pumps for $650 USD.

So good news is that my sixer is up and running again. Bad news is only
the price tag. Could be worse I guess :0

Dru

Dave Plowman (News) wrote:

>In article >,
> R. Mark Clayton > wrote:
>
>
>>My old 735i (same engine) used to leave an injector open or a one way
>>valve leaked, so if the car was left for a few days the fuel line was
>>empty you could hear the fuel pump for a few seconds (followed by
>>little pulses until it was happy) as it refilled the line. If you
>>disconnect down stream of the pump (at the fuel filter perhaps) then it
>>should pump fuel when you switch on the ignition.
>>
>>
>
>Fuel being present isn't the only thing - it must also be at the correct
>pressure. IIRC, the most common reason for the line losing pressure
>quickly is a worn fuel pump. If an injector or injectors were leaking this
>would show up as a rich mixture and poor fuel consumption especially at
>low throttle.
>
>
>