fuel pump doesn't...........

[honourablepickle]

i've had the car in bits for a while now
just stuck the pump back on with some new bits of hose etc
turned the ignition ... no pumping whirring noise
tested the pump off a battery ..... fine
checked the conections to the pump and the fuse ... fine
can some experts advise me on what to do next please
i'm sure the pearls of wisdom from this forum will save me hours of pratting about with a multimeter
thanks in advance
hp

[ed_crouch]

Assuming youve got flapper system, the pump wont run unless the engine is turning.

Try getting someone to ope the afm flap while the ignitions on. Should hear it then. If not, try buzzing out the pump connections for voltage while an assistant opens the flap.

Ed.

Additional: just checked the PDF on wedgepages: the fuel pump is indeed operated by 2 contacts in the airflow meter, which make contact when the flap opens by more than about 5 degrees. This only happens when the engine is either crankng or actually running.

Edited by ed_crouch on Thursday 18th January 21:09

[GreenV8S]

All you can do is trace it back methodically, I'd start with the power and control circuits through the relay.

[honourablepickle]

thanks ed
well while cranking there seems to be 8.6v at the pump - is there a resistor somewhere ?
perhaps i just can't hear the pump noise over the engine cranking ?
i need a six foot long arm so i can listen closeley to the pump whilst turning the ignition
i thought before i took the car to bits that i could hear the pump run when i turned the ignition on - but i might be thinking of my old wedge,or the v8s ......
the sodding car won't start any way
ho hum

[honourablepickle]

actually i think i can hear fuel running back into the tank when i stop cranking ,so the pump must be running
it possibly won't start because it's been sat in bits for months and has some air in the fuel lines/injectors
at the moment it isn't even sniffing
hp

[wedg1e]

Disconnect the fuel return line from the pressure regulator and see if you get flow when cranking.

Even if you do have flow, there's no guarantee the rail pressure is high enough to satisfy the injectors; you really need a pressure guage hanging on the rail (the cold start injector pipe is ideal).

The tank does have a reasonable amount in it, doesn't it? My car splutters below about 5 litres.

One thing you can try is to give the cold start injector a 12v feed and crank the engine. It may try to start from the cold start alone: at least that'll tell you you have sparks and SOME fuel.

Try the old 'flick the throttle open with ignition on' trick and see if you can hear the injectors tick once.

Some other stuff on my webbie...

www.wedgeneering.co.uk/Lucas%20Diagnostics.htm

HTH

[rev-erend]

Nice one wedgie ..

[honourablepickle]

loads of useful stuff
thank you , i'll attack it on the weekend