325 Fuel pressure

[Bonymaenjack]

I've tested my fuel pump pressure today using the Bentley method of removing the return from the FPR connecting a fuel pipe into a marked container ( 30 fl oz ) then bridged the relay position to activate the pump for 30 seconds . the 1st test I had 50% ( 15 fl oz) after 30 seconds , the second test marginally better but still not as specified .The after market pump is a year old , the fuel filter is a couple of months old .The obvious is the pump isn't up to scratch but why would I have two different readings ?

[arrisbmw]

I would suggest best way to check fuel pressure is by using a fuel pressure gauge in line following the fuel filter.
all you need is a cheap gauge some pipe and a couple of jubilee clips.
plenty of post on here about check the fuel pressure and identifying where/ if you have a drop some where in the sys.
iirc Brian Moore has an excellent one, comes to mind.

All you are doing is check the fuel pump is working. its a bit more involved than that, to ensure every thing is right , there are more components.
pump , non return valve in pump , lines to and from fuel rail , filter, fuel pressure regulator. injectors, any issue with one of these will affect you fuel pressure which should be about 3 bar and hold . as our cars don,t pre prime like modern one's do.

[Bonymaenjack]

I would suggest best way to check fuel pressure is by using a fuel pressure gauge in line following the fuel filter.
all you need is a cheap gauge some pipe and a couple of jubilee clips.
plenty of post on here about check the fuel pressure and identifying where/ if you have a drop some where in the sys.
iirc Brian Moore has an excellent one, comes to mind.

All you are doing is check the fuel pump is working. its a bit more involved than that, to ensure every thing is right , there are more components.
pump , non return valve in pump , lines to and from fuel rail , filter, fuel pressure regulator. injectors, any issue with one of these will affect you fuel pressure which should be about 3 bar and hold . as our cars don,t pre prime like modern one's do.

I've fitted an inline pressure gauge fitted just before the fuel rail and the reading I've got has varied up to 40 psi ( 43 psi would give me 3 bar) but then dropping after 10 minutes to 30psi , I've then repeated the test and not getting anywhere near that figure so I'm no wiser atm . I believe I have an injector leak even though they've been refurbished but I'm waiting for santa to provide a new set in the summer , £800+ from the dealer is not a price I can justify to myself atm , Autodoc have back order but they're not due in till July .

[arrisbmw]

I thougt Santa only comes at christmas. LOL
what happens to the gauge with engine running and you remove small rubber pipe from the FUEL PRESSURE REGULATOR.

are you saying when you stop the engine pressure drops.

try clamping the rubber line after gauge but before fuel rail.
if pressure does not drop then , its either faulty fuel pressure regulator or injectors leaking .
if it makes no difference that points to leak in input fuel line oR filter or connectors somewhere or as in my case a fauty non- return valve in the pumP

is the car hard to start when warm ?
the reason i ask is if INJECTORS are leaking when car at rest for say half an hour petrol leaks in to manifold and will flood engine on start up.
however leave car overnight, petrol or alot of it will evaporate and car starts normal after a lay up period.