fuel pump not going --grrr argh

[lord_davros]

i have a probelm with my fuel pump.. it wont go...

i hard wired it for a bit and the pump is still perfect as is all the fuses and relays....


any ideas???

and is it possible to hardwire it to the ignition???

or is there a trigger wire from the ecu to a relay and then to the pump

cheers in advance

[SweetWagon]

yeah the ecu triggers the fuel pump relay...BUT the oil pressure switch by-passes the relay once oil pressure is reached. you could try check the ecu for fault codes first, but did you hardwire power to the relay or directly to the pump? is there power at the fuse or relay? determine that before you go hardwire it into the ignition

[lord_davros]

i just hardwired the pump straight up.... i will check for power at the relay...
if the oil switch isnt working wouldnt it still prime the puel system up?

[SweetWagon]

not too sure why its wired up like that. i think the relay is only used to prime the system and the oil pressure switch takes over when its running and stops you from running the engine if no oil pressure is present or possibly just a backup incase the relay dies whilst driving? in any case its best keeping it like that.

[lord_davros]

yep got power to the relay and thats about it...
would it be ok to hard wire up the pump to the ignition.. is this safe and does the pump run all the time while the car is going or does it turn on and off..
cheers

[lord_davros]

forgot to add that it wont prime or work while engine is on as i primed it with a hotwire

[lord_davros]

so is it ok to have the pump hard wired and going all the time while the engine is on? or will this damage it,
also should i run a relay for it.. cheers

[samuels]

yeah the ecu triggers the fuel pump relay...BUT the oil pressure switch by-passes the relay once oil pressure is reached. you could try check the ecu for fault codes first, but did you hardwire power to the relay or directly to the pump? is there power at the fuse or relay? determine that before you go hardwire it into the ignition

the oil pressure switch runs power to the fuel pump, only if the fuel pump relay fails....so when the relay fails , the oil pressure switch takes over,so when starting the car, fuel pump will not work until oil pressure is sufficient to allow the oil pressure warning light to go off,so therefore the starter motor will operate for a longer period than usual to start the motor

[samuels]

i have a probelm with my fuel pump.. it wont go...

i hard wired it for a bit and the pump is still perfect as is all the fuses and relays....


any ideas???

and is it possible to hardwire it to the ignition???

or is there a trigger wire from the ecu to a relay and then to the pump

cheers in advance

i think hard wiring your pump will always make it work,out of the car,my brother in law had the same problem,he hard wired it just to see if it was shonky,it worked,but once he put it back in tank...no go,so he got a second hand one off me,just as a test,put it in and away the car went,so i'd say you do have a dicky pump

[SweetWagon]

ok heres how to test the relay, how should have constant ingnition power at socket 30, socket 86 should be switched by the ecu. if you have power at these, then either the earth at socket 85 is dead or the wire between the socket 87 and the pump must be broken (oil pressure switch also taps into this wire)

so first test socket 30 and 86(note: may also be 85) with the relay out, if theyre good, put the relay in(make sure it works) see if socket 87 is getting power, if not then socket 85/86(depending on which one is switched by the ecu) is not earthing propery, run a new earth.

if there is still no power at the pump the wire must be broken somewhere from pin 87 and the pump

im pretty sure now that the relay is only used to prime for ~5secs when the car is switched to ingnition, then the oil pressure switch takes over when oil pressure is reached after the car is started, stopping you from flooding the engine etc

[samuels]

ok heres how to test the relay, how should have constant ingnition power at socket 30, socket 86 should be switched by the ecu. if you have power at these, then either the earth at socket 85 is dead or the wire between the socket 87 and the pump must be broken (oil pressure switch also taps into this wire)

so first test socket 30 and 86(note: may also be 85) with the relay out, if theyre good, put the relay in(make sure it works) see if socket 87 is getting power, if not then socket 85/86(depending on which one is switched by the ecu) is not earthing propery, run a new earth.

if there is still no power at the pump the wire must be broken somewhere from pin 87 and the pump

im pretty sure now that the relay is only used to prime for ~5secs when the car is switched to ingnition, then the oil pressure switch takes over when oil pressure is reached after the car is started, stopping you from flooding the engine etc

the only time the oil pressure switch is used,as i stated above is if theres a relay failure...this enables you to get to a service centre to have it repaired,it's a safety feature ....if you would like to call it