Hi guys, A few weekends ago the fuel pump stopped making the wizzing noise when i turned the ignition on. BUT, the car starts, idles, accelerates and drives as normal. All pressures and temps are completely normal as well. Should I be concerned if I can't HEAR the fuel pump? It's obviously working, right? Thanks in advance...
when turning on the ignition (engine not running) you will NOT hear the fuel pump - if everything works as it should the fuel pump should only be audible if you unplug the blue/green safety switch on the fuel distributor and turn your ignition key to on well, seems now everything works as it should ... but clean that switch .
you every day learn something, here: where is that switch? and, what it does, to avoid the noise? Thank you very much ciao
I am suspicious of ANY change in the way something works. IOW, if the fuel pump WAS making noise (could it have been something else?) and now it is not, what changed? Mechanical things don't suddenly fix themselves... As noted, just turning on the ignition should not activate the pump IF your car has the switch mentioned and if it is connected. But...do all the cars have the switch regardless of model year/country? I don't know but I'm sure someone here does...
I'm intrigued - where, how, what is this switch? Fuel pump on my car has always made the consistent humming noise when ignition is on. I'd presume it was broken if it didn't!
Presumably your car has Bosch fuel injection? If so, its on the back of the fuel distributor. The one on mines got a blue connector.Its there to switch off the fuel in the event of a crash or other errant action. I think a few people disconnect this safety feature, as It makes hot starting easier if the injectors/system have a leak.
The safety switch is built into the airflow metering unit -- see this thread: http://www.ferrarichat.com/forum/308-328-sponsored-yellow-compass-group/234634-starting-problem.html Post #5 has a photo of the safety switch connector location.
I believe the QV is a bit like a 328: the fuel pump will only operate when the safety switch is open or the key is in "start". So the pump will only operate when the engine is running --- and, as Michael indicated, the pump doesn't run with the switch on and the engine off. (This cuts off the fuel pump if the engine stalls, so you don't flood the intake with fuel.) ("Continuous" Injection System -- but only continuous while there's intake air to go with the fuel.) You probably won't hear the fuel pump with the engine running. The "buzzing" you might hear with the engine running comes from the "frequency switch" in a CIS with Lambda. That gizmo (near the fuel distributor) is used with the O2 sensor Lambda computer to modify the fuel pressure in the CIS fuel distributor, to tweak the engine mixture. The car will run without the Lambda, but it will run rich. I have a US 328, so I can't help too much tracing the system on an Australian QV.
don`t worry ... yours is a carb car, isn`t it ? buzzing sound is familiar then here we`re talking about 2V and 4V cars with Bosch K-jet fuel injection - on those cars the fuel pump doesn't see any voltage until key is in "start" position and that is when the fuel pump starts working
Like Michael already said; carbed Euro-cars have no built in failure mode things in the fuel supply circuit like switches and so on Ignition on ---> pump running. Best Regards Martin
Michael is spot on! I had the same experience, after having done some work on the car including injectors and fuel pipes the buzzing noise disappeared . I asked the ferrari shop that has just replaced my clutch about this and their explanation was almost verbatim Michael's! I can only conclude that with the work that was done when the injectors were replaced , the switch and fuel pump wires were disconnected and cleaned before reassembly and this rectified the problem. Probbably there was a bad connection before. Best, Nick.
Hi everyone, thanks for your replies, i will check the blue safety switch when i get home this evening and report back on Monday...
Hi everyone, i checked the blue safety switch over the weekend, all looks clean and connected and working as it should be. The car starts fine with no fuel pump noise before ignition. All pressures are good, operating temps are good, the car drives as it should. i think i will stop concerning myself with this issue. Thanks again for all your replies....