FE-FC Holden Discussion Forum

Can anyone help me with the fuel tank [guage sender ] wires . I can't remember how the three wire plug that comes out of the sender unit goes . The old gregorys manual I use only shows one wire to the sender unit from the cluster and a earth. I am only using 7 strand trailer wire from the dash cluster back to the rear of the car and one heavier wire to the fuel pump so when I got to this three point plug I got confused . My other vehicle has a commodore sender unit into the FC fuel tank but the plug is not easy to get to . Thanks in advance Haydn

What model commodore ?

Heres a VN
(http://i943.photobucket.com/albums/ad278/fchoon/VNCommodoremarineschematic718x1024_zps74dafed7.jpg) ($2)

Thanks for that mate .I'll print that out and keep it in the shed 'till I'm finished. This is for the Vauxhall coupe . I purchased a series 2 about 2 years ago with the engine and internal harness and proceeded to tag all the plugs and connectors as best I could . Now I'm getting it ready for its second inspection and have taken the wiring out of the box and and as usual went a bit quick with the side cutters removing what I assumed was not necessary and relocating all fuses and relays under dash . I'm thinking I have [was]a harness from a VR Calais and have removed cruise control , central locking ,climate control ,aircon etc. I have most of the remaining harness working . Yesterday while it was up for diff oil ,I thought I would wire the custom fuel tank [it has commodore sender and pump] I have no worries with the + - from the fuel pump but was confused with the 3 wire plug for the sender unit as I only ran one wire to the sender as per the Greggorys workshop manual that I'm using . If I took the sender out I might be able to understand how it works . One terminal would be an earth and one would go back to the guage but does the other draw power from the fuel pump + . Like I said ,no sign of this in the manual . If I have to I'll pull the FC tank out of the other Vauxhall and have a look as I've  modified a commodore sender unit for it ,but its on top and hard up against the back floor . Would be thankful for any info on where these wires go . Cheers Haydn   

Hi Hadyn, I don't have a diagram to look over, but I think the 3rd wire may be for a 'low level' warning indicator, as some of the commodore models had this feature..  Hope this helps. Cheers Matt


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Thanks Matt, thought it might be something like that . I have an old Saab from the late 90s' [Saab built by GM with and Vectra and Astra parts] and it gives an estimate on how far the existing fuel will get you . So if you factor in that the computer is a Nissan Pulsar one with a different memcal and that on these early V6's, used masses of relays to make up for the lack of computer functions then you don't have to ask why your microwave has a button on it that says microwave and you have to hit this before you hit start EVERYTIME . Cheers Haydn

Matt I don't have power on the green-white wire that goes from the computer through the engine harness to the fuel pump relay [trigger-switch] .I have hot wired from the ignition to trigger relay to check fuel pump and that's fine . The other series #1 VN keeps pumping fuel 'till the oil pressure drops off. I believe this was a feature [mistake] of the VN . As you seem to have a handle on this wiring stuff I was wondering if you have any ideas. I could probably power the wire from the relay end and check back at the computer with test light . Anyway I'm not far from firing it up .Maybe I should double check the trans. isolator switch before starting ,don't want a new back door in my shed . Cheers Haydn

False alarm, sorry . I powered back through that GW wire to the comp.and the wire was fine so plugged it back in and powered through the computer and found power was exiting a KB wire which I cut off [idiot] . Turns out that was the power wire through the anti theft module that I so carefully [not] removed . So all is good ,thanks anyway . Haydn 

Still having problems with this harness . I think the problem is mine .The body harness is Calais and I've removed the anti theft module [trip comp. and cruise control] and can't find any information on how to by -pass it . All systems are working ,ign. efi. start relay all lights and ass. but I have no spark at the plugs but have + power to the coils [which I have changed twice] and nil injection but do have + to each injector and will operate individually if earthed with jumper leads . Have also changed to early vn ignition coils and ecu thinking that the memcal. may be the problem . Also changed the crank sensor . The motor will crank over but doesn't start which is frustrating because the diagnostic [check engine light ] is flashing 12 . So with no - pulse to the coil and injection can not start the engine . So I'm wondering if there is a difference between the body harness in vn and vp that would have caused this ,or different wire placements on ecu . Or is it just because the body harness is stripped and spread across the floor under the dash and I may have removed an essential earth connection . Or is it something to do with the gnd pulse wires on the plugs on the back of the instrument cluster as I'm not sure of where the get this pulse from [ecu or direct from crank sensor] .Does anybody out there have any ideas that may help [short of petrol and a match] as I'm really stubborn and would rather learn how to sort this . Cheers Haydn   

Remove VATS from memcal...
Send me your computer if you don't know what I'm on aboutt

An old friend came around to ask me to join a new local car club last evening, while I was trying to sort the fault, and sent his 18 year old son over this afternoon . To shorten a long story ,his high school class built a VN demo. car last year . He simply twisted a few wires together while telling me that the demo was not running a dash and you just have to join the wire that are the same colours and it should run .I turned the key and it started and idled . So because I removed the radiator and alternator to check the wiring I had to shut it down . After the young fella left I had a closer look at what he did and it looks like there is a brown\yellow wire twisted in with the pink wires at both ends of the body harness . I'll take a closer look at what he has done in the morning  . But it works so now I can put it all back in . Cheers Haydn

must be a big relief.  It remind me of the time when electronic tuning came into TV and VCR's.. I used to tell my customers to get their grand children to do it.  They usually succeeded.

Yes I totally agree . Back in the 80's went to mining and energy building in Brissy as part of a computer programming course I signed up for. Floor after air conditioned floor of nothing but huge computers . Now your grand kids have more computer in their mobile phone . Its a brave new world that we are ill-equipped to deal with . And for the most part our problem is we over think . And yes I am happy to be over this hurdle and on the up side every circuit ,relay, fuse ,crank sensor, ignition coil ,wire ,dash circuit, plugs, connectors, have all been checked over . Now have a large fish tray full of pretty coloured wires . Haydn