280zx Fuel system.

[fae821w]

Just had my 280zx in to the local garage for a fuel pump change.

Question:
Should the pump run continuously when the ignition is on, which mine is, or should it stop pumping once fuel has filled the system?
(I can hear it ticking away all the time)
If its supposed to stop, how is this achieved by a switch/relay or something?

Thanks, Andy.

 

[Huw]

Hiya

I'm sure I will be corrected if I've got this wrong but the pump will remain on whist the engine is running. If the alternator stops and the oil pressure decreases then the pump will stop even with the ignition on. This I think is to stop the fuel supply if there is a problem if the engine stops or cuts out when u are driving. I would check the fuel pump relay.

Huw

 

[Alphabettispaghetti]

It that it'd not wired off the acc point of the ignition?

 

[candy red]

if you turn the ignition on without cranking the engine you should hear the fuel pump run for a few seconds to pressurise the system then the pump relay will click and turn pump off this is controlled by the fuel pressure regulator, until started then the pump will run until turned off ,if it goes off while running the engine will die which would properly indicate pump relay fault or bad connection i think but don't worry Mr F will be along soon to correct me if wrong

Derrick

 

[Mr.F]

The correct pump wiring and location of the relay(s) changes from early to late model 280ZX, but the effect should be the same - ignition on, pump runs to prime the system. If engine not started, pump will switch off after about five seconds. The relays are triggered by the ignition switch but are also looking for signals from alternator and oil pressure switch - if either is not there, pump should automatically stop. In the case of engine failure and loss of oil pressure or sudden engine stop in an accident, you shouldn't have 60psi of fuel pressure shooting out of a severed pipe...

 

[fae821w]

Thanks to all for the info, after speaking to Mr F his thoughts are to suspect the large cad plated relay under the bonnet - part number 25236P7102.
Has anyone got a spare I can purchase please?.
Andy.