fuel pump doesnt prime

[Burnout_bro]

after swapping 3 different fuel pumps aroun none of them will prime up on startup, i have no idea what is going on all the fuses are good so i dunno?

[dodgy]

Are you installing them upside down?

Have you got power to the pump, test with probing with a test light

[Matt_vp]

is fuel filter blocked?
When u turn the ingition to on before u start it does the check engine light come on, like it does.

[Burnout_bro]

nah i put the fuel pump in the right way, this is the second one i put it its pissing me off

[Not_An_Abba_Fan]

I assume you know how to prime it? Crack the fuel line on the injector rail, turn the key on and off until you see fuel at the rail. If you're not getting any fuel up then I would suggest the pumps you are using are buggered. Or the filter is blocked.

[Burnout_bro]

so u cant just put a different fuel pump in, you have to do what u said and what do u mean crack it?

[Morton]

Okay, I would suggest you try a few things first:

1) Quickly slap in a new fuel filter. They're cheap and easy to do. (Make sure it points the right way, mmmkay? )
2) Change your Fuel Pump Relay (just swap it with the horn relay and see if it works)
3) Change the Fuel Pump Fuse
4) Check the wiring that the relay and the fuse plug into. I had burnt terminals in my fuel pump fuse socket that gave me ALL SORTS of trouble.
5) Check the plugs to your fuel pump with a multimeter (while someone turns the ignition)
6) Check the pump relay circuit with a multimeter (while someone turns the ignition)


And that should tell you where your problem starts

I assume that what our Abba Fan is saying, is that a good way to check if your pump is priming, is to disconnect the inbound fuel line in the bonnet, point her into the air, and then turn your key to "On" (without starting it), and watch to see if any fuel spurts out.

(BTW: I assume you mean the pumps don't prime, AND they don't work at all? i.e. your car isn't running? Not just that they don't prime, but they work normally otherwise?)

[Not_An_Abba_Fan]

Sometimes you can get an airlock in the fuel line so the fuel pump will not pick up fuel and send it to the injectors.

Yes, what i meant is undo the fuel line from the pump to the fuel rail and see if any fuel comes out, this will also get rid of any air in the line.

Another thing to check is the fuel pressure regulator and the return line valve. Clamp off the return line to see if it helps.

[Morton]

Ah ye, true dat. Forgot about vapour lock. Good point

[Burnout_bro]

hmmmm put a fuel filter in today no difference, still dont hear her starting up when the ignition goes on, i know where the pump relay is but where is the pump fuse?

[Not_An_Abba_Fan]

Just found out that the fuel pump is operated off the oil pressure switch circuit. If the OPS is buggered the fuel pump won't work. Try changing that and see how you go.

[Not_An_Abba_Fan]

Also, a test to see if your fuel pump is actually working look here http://forums.justcommodores.com.au/...ead.php?t=2565 There is a link there to a word document that shows the ALDL connector. Put a paperclip from the fuel pump test to earth and if the pump makes a noise then you will have ruled out the pump, the relay and the fuse. If it doesn't make a noise and the relay is ok the fuse is the one closest to the drivers guard in the fuse box.

[Burnout_bro]

where is the oil prussure switch circuit? and the thread doesnt work

[Not_An_Abba_Fan]

If it is the oil pressure switch you have to change the switch itself. Try the link now.

[BrianH]

There seems to be a lot of guessing going on here with very little in the way of results.

I have a VP 6 but I think the wiring is the same for the VN. The fuel pump fuse on my car is number 21 and it is under the bonnet. If you stand in front of the driver's side headlight and look at the relay box, the fuse is the one on the far left on the top row. It should have an orange wire running from it to the pump relay which is further along to the right on the same top row as the fuse. The fuse gets its power via a red wire from the centre fusible link.

A buggered oil pressure switch will not stop the pump from working. It is wired in parallel to the relay and provides a backup if the relay fails. It will direct power through to the pump providing you crank the engine long enough for the oil pressure to build up high enough to operate it.

I am not sure what putting a paper clip into the ALDL connector then to earth is supposed to do. All you are doing is earthing the pump circuit without it going through the pump. This should blow the fuse the moment the ignition is switched on.

The connector should have a violet wire in it. It is spliced directly into the red wire running from the relay to the pump. If you put 12 volts into the violet wire terminal in the connector, you send power directly to the pump bypassing the relay and oil switch. This should make the pump run providing there is nothing wrong with the pump, the earth for the pump or the wire connector on the pump.

If the pump runs when you do that then the problem is either back in the relay, the circuit or the ECM.

The circuit is very simple. An orange wire runs from the fuse to a triple splice inside the harness then on to the relay. The other two wires in the splice are also orange and go to the oil pressure switch and the theft deterrent emergency switch. From the relay a red wire runs to the pump. This is the wire the violet one from the ALDL connector is spliced into.

The relay is operated by a 12 volt supply through a green/white wire from terminal A1 on the ECM. When you turn the ignition on the ECM sends the 12 volts through to the relay but it will cut it off in two seconds if it does not receive a cranking signal.

Some of these wires pass through harmess connectors like YE51 near the relay box under the bonnet and YB38 near the fuses under the dash so you could have problems in them.

If your problem is the pump will not run then you should be able to work it out easily by testing the pump and checking the circuit, relay etc.

Brian

[Burnout_bro]

champion mate

[Phoenix21]

im guessing you got it going then ???/

[Burnout_bro]

mate still not going, starting too piss me off and running out of money, its my second car which makes it alright, bought it in that condition but i dunno if the guy has stuffed me over, all the fuses and relays are okay and the pump is fine and the filter is new, so i dont know its a real brain teaser

[Not_An_Abba_Fan]

So what is the exact problem you are experiencing? Just that the car won't start? Or can you not here the pump when you turn the ignition on?

[Burnout_bro]

fuel pump doesnt start up, used the one out of my other vn and still doesnt work, im sick of showering 4 times a day after me smelling like fuel, i think i will just sell it and let someone else fix it

[Matt_vp]

does the check engine light come on when u turn the ignition to on.

[Burnout_bro]

havnt checked why what would that mean

[Matt_vp]

i had a problem with my fuel pump not getting power and my check engine light wouldn't come on with the ignition turned to on. so if u check and its not coming on i can tell u how to get it to work, but im still unsure of what was causing it.
Matt

[Not_An_Abba_Fan]

Get hold of another ECU if you can and change that, see what happens.

[BrianH]

Are you getting power at the pump when the ignition is turned on? You will need a test light or a multimeter to check this and you may need someone to assist you because you will only have the power for two seconds unless the engine is cranking so it is no use turning the ignition on then walking down the back to check it.

If you have power but the pump will not work then check the pump earth. The wire colours I gave you yesterday came from the factory engine manual but I just noticed the wiring diagram manual gives more detail and shows more colours and connectors. The wiring harness going to the pump should end in a round white plastic push in terminal about 40 mm long. It will have a violet and a black wire going into it. From the pump half of this connector there should be a red and a white wire going into the pump motor. The white one is earth and it changes to black inside the connector. The black wire runs back to the connector I mentioned near the under dash fuses then into the main harness and is earthed at what the book says is a body earth point at the right hand wheelhouse (drivers side front wheel) for the main harness ( the big one that goes through the firewall and contains the under bonnet relays and fuses and the instruments) and the battery harness ( the one connected to the battery and starter motor).

That is the point where the fuel pump is earthed. If you have a multimeter you should get a reading if you connect the leads to the black wire in the white connector at the pump and a clean point on the body. If there is no reading then you have a break in the earth circuit. Find the body earth point near the wheel and clean it. Make sure the wire is properly connected to the terminal that is attached to the earth point. The same applies where the wire goes into the connector down the back. If there is still no reading you will have to find the under dash connector because that is the only other break in the wire.

This under dash connector should be somewhere near the driver's knees. Half of it is attached to the harness going down the back and the other half to the main harness behind the dash and instruments. It is rectangular in shape and has provision for four wires. The four coming up from the rear will consist of two blacks plus a violet and a violet/red. The black one on the same side as the violet wire is the one you want. The other is a combined earth for the rear lights and fuel gauge sender unit.

Once you get power to the pump and it is earthed properly it must work. I could not imagine all of the pumps you have tried being faulty so the problem must be in the wiring.

Try that and let us know what happened.

Brian