operation HQ under way.
Got me stumped - more fuel issues
long story short i got a new pump it was faulty and i returned it, got lazy and haven't fitted a new pump yet because my old one has been working.
now last 2 nights we have been driving (lights on) after an hour with the missus driving (she is on her l's) driving on a flat straight road, the car just cut out. pulled over and restarted. i thought yeah it happens and ill fit the pump on the weekend.
today on dusk, driving down to a well lets say paddock to give the dogs a run same thing but i was driving, i was in a 100 zone doing 100 with cruise on and it started to give a dead miss (like a thud) once or twice than it lost all power and cut out after about a minute. no engine light on so I'm thinking fuel again.
i know the fuel pumps working because its noisy, but still making full pressure (i have had a gauge on it) got it restarted and it was still running like crap, made 40km/h thinking it was out of fuel but it had 1/4 tank (its not the hose that has been done with a weld back on the top of the tank) stooped again and turned my headlights off. next minute (or split second) the engine jumped back to life and the pump got relay quite and i was off. no more issues.
my long winded question is why would turning off the headlights cause the pump to function correctly (alternator is charging at 13.5v with lights on) vr v6 berlina wagon.
It sounds like a bad electrical connection or earthing problem somewhere.Check the alternator wiring ,especially the large single lead,this lead can get hot and then it corrodes and causes all sorts of problems,it happens under the wires sheath,so sometimes you cant tell the condition the wire is in unless the sheath is cut back.Some can actually melt the sheath as well. You can read a sticky thread about it at the top of the VR-VS page titled "V6 owners check this out".
Donating Member
The headlights on a VS (prob also the VR) auto turn off if you turn the ignition off and open a door.....so, going along that line of thought, I'd think about what other scenario has ignition off/lights off.......
So, I don't know what does the above - is it BCM or ECU or both, but maybe swap them if you have a spare.
I'd also check the ignition switch under the key cylinder as they can make intermittent contact. How is the oilpressure switch? it forms part of the power supply although it shouldn't affect the headlights.
Maybe also monitor the volts all the time....watch for fluctuations...maybe there is an intermittent short in the alternator which drains power for just a second or two....Bretts suggestion is very relevant.....the fuel pump should not be noisy unless the pump or the inner tank pipe is touching the tank - it's immersed in fuel which damps out vibrations (or should do).
Last suggestion...sell the car
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check for fault codes... possibly a CAS?
operation HQ under way.
lol i just bought it......Originally Posted by hako
i do have another alternater lead lying around but by g they are tiny.... my sterio lead from my old setup was bigger...
tank is fine new hose in side
i managged a 300km trip on sunday to see the old girl for mothers day, no dramas.
ill check with tech 1 tomorrow for codes and fuel trim data on a drive a see what i get. its been a bit heavy on fuel too (well more than the sedan i had) but i was putting that down to wagon being heaver.
would a bung bcm cause a fuel pump to "drop out"? or cause it to have a reduction in voltage?
Just checking out a wiring diagram and theres no connection between the fuel pump and BCM that I could find.
operation HQ under way.
just to let you know, the fuel pump fuse powers up the bcm, well one lot of power any ways, if that blows the central locking wont work.
I just checked it out in the diagram.Fuse 23 under the bonnet connects to both the BCM and fuel pump via an orange wire.Theres a few different power feeds to the BCM.I didnt see this one before.Thanks.
Woodgrain Nut
The BCM controls the immobiliser. As a theft deterrant the immobiliser cuts power to the fuel pump. If you have a dodgy BCM that is enabling the immobiliser at the wrong time then that would do it.
Moff_man have you noticed whether your engine immobiliser light has been coming on when the power cuts out?
operation HQ under way.
NO tech 1 shows fuel pump still operating and i can hear the pump, problem is now solved due to a new fuel tank. the old hose that was inside had disintegrated and i cut it open and replaced, also cleaned it out as much as possible but i think the crap was stuck in the venturi compressed air also didn't help. still did it. replaced the tank and all is well. a new tank was cheaper than than the cleaning crap that possibly wouldn't work in this case.
Looking through the VS wiring diagram,the only relationship the BCM and the fuel pump have is one of the BCM power feeds shares the same fuse(number 23) as the fuel pump.Thats it.The BCM has no other connection to the fuel pump (in these diagrams anyway).And no control over it.Fuse 23 is fed power straight from the main 60A fusible link, which then directly feeds the BCM and the fuel pump relay.
Last edited by Brett_jjj; 26-06-2010 at 04:48 PM.
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