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Vp Commodore No Fuel Pump

Started by Stedz_lc , Aug 29 2008 10:09 PM

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35 replies to this topic

#1 Stedz_lc

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Posted 29 August 2008 - 10:09 PM

Hi all
Got a hard one, Vp commo V8 Efi engine cranks got spark but the fuel pumps dont run or even prime checked Relays replaced ignition module replaced dizzy (All had to be done anyway) three different Ecu's still nothing any hints tips etc? Im goin to start back probin n runnin round wit test light tommoro so any pointers be good!?
By the way just to make this a real hard one all the the running gear is an HZ.
Cheers
Ed

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#2 _evil UC hatch_

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Posted 29 August 2008 - 10:14 PM

the first thing I do would be see if the pump is getting power, if it is then the pump is faulty, if not, follow the wiring back testing it in any connections/switches etc until you find power, and then the source of the problem should be obvious when you find where it is

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#3 rodomo

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Posted 29 August 2008 - 10:21 PM

While it's cranking, get someone to belt the bottom of the tank behind the drivers rear wheel.

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#4 Stedz_lc

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Posted 29 August 2008 - 10:31 PM

Pumps arnt gettin power, if i bridge the relay (fuel pump relay) they fire up, where do these in a stock Vn/Vp get power from? Its so hard as its in a HZ but im tryin to follow orig wire diagram for Vn/Vp if i had this diagram would help

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#5 rodomo

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Posted 29 August 2008 - 10:34 PM

I've got a book here if you want a lend?

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#6 Stedz_lc

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Posted 29 August 2008 - 10:38 PM

Really? That would be AWESOME! Id just like to know in stock form what tells it to power the pumps etc so basically the fuel pump wiring diagram! Ill pull the wiring apart tommoro n trace it back but was hopin someone here might have had similiar issues n its a faulty part not wiring issues, but i may take u up on that offer rob!

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#7 rodomo

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Posted 29 August 2008 - 10:40 PM

Are you working in the morning?
I can drop it in.
PM me your ph. no.

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#8 _evil UC hatch_

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Posted 29 August 2008 - 10:41 PM

A relay typically has 2 power sources, one switching power, and a direct power source, ie when you turn your ignition(dunno if its computer controlled or what there) on (switching power) and the direct power source is usually from either the altenator, or battery

has this setup been running before or are you in the process of getting it going?

Edited by evil UC hatch, 29 August 2008 - 10:45 PM.

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#9 Stedz_lc

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Posted 29 August 2008 - 10:44 PM

been running, yes rodomo workin in the mornin! il pm number- There from 8 til 12.0

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#10 _evil UC hatch_

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Posted 29 August 2008 - 10:47 PM

ah, so its more than a case of finding a power source then, youve got to look for a fault and thats always a pain in the arse. have fun

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#11 FastEHHolden

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Posted 29 August 2008 - 11:23 PM

hows the start fuse look?

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#12 Stedz_lc

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Posted 30 August 2008 - 07:49 AM

LOL Thanks Evil Uc! Haha I know im in the sh!t but well get there, yea goin to check all fuse's today test them all!

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#13 _lx-304_

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Posted 30 August 2008 - 09:19 AM

hi there,if your pumps work when you bridge the relay, then you need to check the pink wire with black stripe,from memmory it comes from the small plug on the ecu and runs to the ignition relay.this is the wire that primes the injectors when you turn the key on. i know this because i had the same problem when i wired up my hatch.either that the green wire fron the fuel pump relay is the signal wire to the computer which turns the fuel pump on.both these wires can be checked by multi meter.

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#14 _lx-304_

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Posted 30 August 2008 - 09:37 AM

hi again i have just looked at relay box and f/pump has 2 power sources,1 is from fuse(orange),the other is green signal to comp.however no power gets there without the ignition relay which is the one under the dash inside the car below steering column.if this relay is broken you will have no pumps at all,but will still have spark.hope this helps.

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#15 _shibby_

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Posted 30 August 2008 - 06:04 PM

Thanks lx-304, no pumps and no injector pulse? Ive got nothin and now it seems i have no Ecu/engine light.. Rodomo Suggested earthe prob so il look at that next, and try find the igntion relay!

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#16 _lx-304_

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Posted 30 August 2008 - 06:37 PM

some how i missed the part that it was in a hx,so the ignition relay may not even be there,depending on how it s been wired up.i have a relay box an harness out on the floor if you get stuck,i can tell you exactly which wire to check.it might save you a bit of time climbing in and out of the car and looking for the right wires.

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#17 Stedz_lc

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Posted 30 August 2008 - 07:58 PM

Any help would be great lx-304

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#18 _luv the uc_

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Posted 30 August 2008 - 08:10 PM

Could it be an Anti theft or immobiliser fault?

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#19 _Yella SLuR_

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Posted 30 August 2008 - 08:40 PM

While it's cranking, get someone to belt the bottom of the tank behind the drivers rear wheel.

^ What he said. Typically happens when the fuel pump shits itself. Happened to me in the VN. Just grab a new fuel pump and fit it. It's on the end of a Torrie looking fuel pickup/guage stalk.

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#20 _hatcher_

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Posted 30 August 2008 - 09:06 PM

OK, the pump is powered two ways. When you first turn the ignition on, the computer will energise the relay for a few seconds (to prime the fuel system). If this is not happening, I would be looking in the ECM (computer) area. Since you siad you have tried a couple of ECM's, I would say the ECM itself is not the problem but a power supply to it (or Earth). Check fuses etc...
If you are not getting a "check engine" light coming on when you first turn on the ignition on, this is also proof the ECM has lost power/earth (there are several power feeds and earths going to the ECM)

Second way the pump is powered, is once the engine fires up and the oil pressure gets up, the oil pressure switch provides power (On VN/P motors) This is not happening to yours because of the first way is not happening.

Cheers,
Dave.

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#21 _lx-304_

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Posted 31 August 2008 - 07:28 AM

pretty sure it gets no power from oil pressure switch,as i never connected it up and used a mechanical one.the power for the fuel pimp is as follows.there are 4 wires on the relay 1 is orange from fuse,2 is black=earth,3is purple=power out,4=green signal wire.the signal wire runs straight to the computer.seeing as though none of these wires are hooked to ignition,which is what you need to prime in the injectors,this is where the pink and black wire comes into it.it goes from thick pink wire which is ignition just below steering column runs under the dash to the computer and also a test plug.when the key goes to on they will prime and then in the crank position when there is spark is when the computer turns on the pump.this is so if you hit a tree,it wont pump fuel all over the place because the motor has stopped and no spark.also if it works when you bridge it then the earth is good enough,otherwise it woulnt work at all.as i said before if you are still stuck,contact me and i will look at mine which is laying on the floor exactly how it would be in hz.cheers dave.

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#22 Stedz_lc

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Posted 31 August 2008 - 09:13 PM

So ok lx-304 what combines injector pulse and the fuel pumps together as there the two things i dont have!
I can make the pumps run ie bridge the relay n away they go, but then still no pulse, do u think my prob could be from ign to computer?
I didn't get chance to look today! might have a play next weekend no room in the shed atm to play at night! (bring on daylight savings)

Yella it doesnt' have an internal pump runs surge tank etc (its not in a Vn)
Thanks for everyones help!! Keep plodding along! When its done well put it up in members cars

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#23 Stedz_lc

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Posted 31 August 2008 - 09:18 PM

Also orange power from Fuse or fusible link or both? Is this igni power or constant power

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#24 _lx-304_

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Posted 31 August 2008 - 09:35 PM

hi there,the first thing you need to do is with a test lamp,test a6 on the computer plug(pink and black).this should have power when the key is turned on.if there is no power then find the end of that wire and make sure it is joined to the pink one in hz harness which is ignition.are you using the relay box from the donor car or is it a bought.ideally you should have the original relay box with your hz engine hrness plug on it and that should be plugged to the car harness.this is the plug with red,purple,pink,blue and grren.red is power in to the key,pink is ignition to hte key,purple is starter motor and then oil and temp.it hte pink one on this plug that the pink and black onne should be joined to to make the injectors prime and turn off.if you are still having drammas and you have wires everywhere you cant find.then it may be easier to rewire it as it is only 4or 5 wires and takes not long at all and good do it over the phone.this could be quicker than spending time in the car.