Engine: 2.3 Carb B23A/B230K: fuel pump...main or intank issue

[honestjoe]

Hi everyone...recent development with my stalwart invincible 240....turn on ignition key before engaging starter and i can hear(what i think is the main ) fuel pump make a short sharp buzzing sound..almost like its priming itself up..i"ve never heard this before..not unduly worried as car starts like a dream...but could it be the start of something more serious?...i can remember paul or ian mentioning that you should be able to hear intank pump humming when ignition is in first position..i have to say that i cannot hear it with petrol cap removed...i did search forum for this issue with limited results...appreciate any thoughts...regards hj.

[Glen Morangie]

In my B200F 240 I can always hear the fuel pump buzz, it was less audible on my K-jet B200E in the 740, but there nonetheless.

My 2.3 240 has a carb and mechanical fuel pump, so no buzz there!

[Paul Clifton]

I presume you picked the wrong title honestjoe and that yours is in actual fact an injection car. If that is the case you are correct in that the pump does do a one second burst when ignition switch on to prime the system. You probably would not hear it when you start normally as you would go from off straight to start. Do not worry this is entirely normal.

Paul.

[honestjoe]

Thanks glen and paul for replies , it has a cisac solex carb which also has the dreaded pulsiar vac system..its just i never noticed the pump priming before and i have had the car nearly four years.I did mention previously that i found an early mobile phone communications box screwed into the floor in the tailgate floor panel..i must remove this..perhaps i will take the floor out and localise the sound.....cheers hj.

[Paul240480]

Honest Joe When/if your in tank pump decides to 'buzz'. You will know without doubt. The noise is continuous & very obvious when the tank is around 1/4 full or lower.

Mine has been like it for some time now. They will keep on going even so. It means that the main pump works harder tho'.

[honestjoe]

Hi paul...thanks for that..it is odd as it is only a short burst...2 seconds i reckon..could it be air/vapour in the system i wonder?...regards hj.

[Paul Clifton]

Hang on we are getting at cross purposes here, if its a carb car it has an engine driven mechanical pump!!!! so what the noise is don't know.

Paul.

[Glen Morangie]

Originally Posted by honestjoe

Thanks glen and paul for replies , it has a cisac solex carb which also has the dreaded pulsiar vac system..its just i never noticed the pump priming before and i have had the car nearly four years.I did mention previously that i found an early mobile phone communications box screwed into the floor in the tailgate floor panel..i must remove this..perhaps i will take the floor out and localise the sound.....cheers hj.

Nothing dreaded about the CISAC or the pulsair! Well mine have served well for 18 years now - but you wouldn't have had an in tank pump fitted AFAIK (there was a very early version on the B23A which I haven't seen - and Volvo do like to try everything once).

Could it be a relay buzzing, you won't have a fuel pump relay either, but I'll post back if anything comes to mind.

(edit) Could someone have modified it and fitted an SU fuel pump - they buzz as you describe (and can be used in place of a mechanical pump). Maybe you should trace the fuel line in the engine bay and under the car, so you can be sure.

(2nd edit) and thinking on - some 240's had a mechanical vacuum pump for the brake servo - did those have an electric fuel pump? I think there's only one pump mounting on the engine.

Honestjoe you may have one of the early (and quite rare) versions.

[honestjoe]

Morning everyone!...i think more investigation is required on my part!...feel abit of an idiot regarding fuel pump applications....i"ll be back!...thanks again..regards hj.

[James_N]

when i get below half a tank of petrol, i can also hear a constant buzzing which i also presume is the in tank pump. How much are these to replace?