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Re: Fuel Pump operation on E12

On Wed, 28 Aug 1996 owner-bmw-digest@domain.elided wrote:
> 
> >> About hard starting due to lack of fuel pressure when the engine is cranked because the fuel pump
> doesn't begin to function until the engine begins to crank...
> 
> Eric Tangen  wrote: 
> 
> > The pump operates: 1. while the starter is cranking & 2. when the flap inside the air flow meter
> moves >off the fully closed position (there is a reed switch under the plastic cap on the AFM that
> senses this). 
{stuff deleted} 
> My question:  Is is possible to get a fuel pump relay (or other solution) for the E12 that will
> prime the fuel lines (run the pump for a second) so the system is already pressurized when the
> engine begins to crank?
> 

Having played around with the fuel pump circuit of my '80 528i, I thought
that the combo relay (the double relay near the master cyl) had a few
second time delay that activates to presurize the the system included in
it.  It only works the first time that the key is turned.  Since there are
various electronics inside the relay I presume that their function has to
be for a time delay why else would they be there.  (I know for sure that
my 320i runs the pump for a few seconds when the key is first turned) 
Next time I remember, I'll check to see (hear:) if my 528i primes the
system. 

*****************************************************************************
Walt Barie  (barie@domain.elided)
'82 320i 
'80 528i
'80 Volvo DL