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  1. #1
    Join Date
    Dec 2018
    Location
    Bristol
    Posts
    16

    Rover V8 Wiring (Ignition, Fuel) Fuel Pump not working

    Hi all,

    Recently joined, I have a Dax 1984 fitted with a RV8. Won't start, seems to have several problems, latest being no spark from coil, I'm thinking the Lumetition ignition module is toast.. Coil has 12v but no sparks even when I try shorting the lumetition system (As per factory guide). Have a replacement electronic dizzy setup I intent fitting, but guess first challenge is getting fuel!

    Now, the wiring is looking tired and messy and whilst I'm trying to avoid a complete rewiring job I'm nearly at my end with wire chasing.

    Please realise I'm not that experienced, but dangerous with YouTube!

    So, there an issue in the fuel pump power feed.

    The pump works when hooked direct to battery but does not initiate when the ignition is on or cranking. I've tried chasing the wire from boot, under carpet (Who knows what happens to the line under there, but assuming its the same colour coded wire that goes in), behind dash to what looks like the steering column switches, which just doesn't make any sense to me. It did work when it first arrived, so a little stumped as to what's changed...

    We're talking glass tube fuses era and thinking the whole thing should just be ripped out and start again... Although, that's a lot of wires.

    I'm in close territory to totally removing the dash and unclipping all the zipties, as there is a spaghetti junction behind there and lots of splice work and additions making it near on impossible to trace. And rewiring with the 12 circuit loom I bought - All I really care about right now is starting the car and being able to move it around.

    So the questions are....

    1) I presume early car pumps don't feed from oil pressure switch at the pump and have some direct feed, typically...?
    2) Wiring should go, Battery, thick gauge to starter solenoid, then positive line picks from here to oil pressure, coil, ign module, pump?
    3) Ignition switch wiring, thinking rewiring a separate circuit and disconnecting the old one to just ignition, fuel - What are the typical terminals in the rear of the ignition barrel? Lucas if that helps...

    Any simpleton advice to be given from your wisdom?

  2. #2
    Join Date
    May 2004
    Location
    Finchampstead, Berkshire, UK.
    Age
    53
    Posts
    3,527
    1) Nope, more usual was to feed from/via an oil pressure switch.
    2) Or battery to fuse block, to ign switch back to fuse block to feed ignition live circuits.
    3) Not sure.

    Engine needs Fuel + Spark + Air.
    Air = throttle plate moves when throttle peddle pressed
    Fuel = Does pump run and does fuel go through carb?
    Spark = Does it? If not the start here!

    Regards + Welcome

    Jim
    GD Mk3 Jag based
    Supercharged LS1
    T56 Gearbox
    3.54 LSD Diff
    AP Vented front brakes
    Outboard X308 Vented rear brakes

  3. #3
    Join Date
    Oct 2006
    Location
    Toton, Nottinghamshire
    Age
    45
    Posts
    821
    Hi,
    I have a similar era DAX with RV8. It has a large red plastic electric isolation key in the drivers footwell. The engine will still crank when it's off but no 12v to the ignition and pump etc. My apologies if you've already checked this out but it could be the source of all the issues you mentioned.

    Check the resistance across the coil terminals (leads disconnected) it should be a few ohms. They can burn out if left powered up too long without being able to discharge.

    Russ.
    Joint Area Rep - East Midlands Region
    1984 DAX Cobra
    Rover 3.5 V8 with Holley carburetor.

  4. #4
    Join Date
    Mar 2005
    Location
    Northampton
    Posts
    1,023
    Check the fuses with a meter - I was stranded by one that looked fine but had in fact blown. My car uses blade fuses and you can get blades now where an LED lights up on them if the fuse has blown.

    I echo Russ’ point about the immobiliser switch - check there isn’t a second one somewhere, and look for in-line fuses in odd places away from the fuse box. Is it a duff relay somewhere ?

    More advice from the FWIW collection - take notes as you go along. I’m also assuming you have the wiring diagram from the original donor to give some clues about what the wire colours could be, but I’m guessing your car is a bit like mine - wires can change colour at various points along their length. Tempting though it is to rip the whole lot out, start again and restore order from chaos I think you’d be entering a world of pain and would pretty quickly wish you’d never started. One garage of my acquaint often doesn’t bother trying to find electrical faults but just puts in a new wire as it is less time consuming and therefore cheaper.

    Good luck, if all else fails I’ve called in an auto electrician who’s usually spotted and fixed it in 5 minutes...
    David (AKA Firestarter29)

    Lead, follow, or get out of the way.

  5. #5
    Join Date
    Dec 2018
    Location
    Bristol
    Posts
    16
    Made some progress today, turns out the indicator feed was tapped into fuel pump and that connection connects directly to fuse box. So now I have a pump again, celebrations.

    Have new electronic dizzy setup on route, actually had one arrive but mines a P6 not SD1 so needs a slightly different distributor.

    So now we have fuel and now we need new spark

  6. #6
    Join Date
    Jan 2015
    Location
    Paignton Devon
    Posts
    282
    Beware of "just tidying" your wiring it can lead to a world of pain!https://imgur.com/a/aNhBhpz������

  7. #7
    Join Date
    Dec 2018
    Location
    Bristol
    Posts
    16
    Ha! Mines all tucked behind dash and to be fair isn’t too bad but is that old that the amount of dust in areas rules out cable chasing. Think I’ll be in a world of pain at some point so going to make dash loom, front loom, rear loom to modularise the whole system. It won’t be in one go though, going to renew as needed. Few suspects in the system.

    Fingers crossed the new dizzy and ignition system gets decent power and big spark to make a nice bang

    Lumeition system was actually getting really warm on cranking yesterday so it’s definitely doing something. I’d almost bet it’s salvagable but for peace of mind bit the bullet for a new system so I shouldn’t have to worry about it in the short term at least.

    Revisiting the wiring, we have power to starter and then feed to ignition which feeds fuse box, so looks like it’s wired up correctly and I’ll replace cabling on this circuit with the same layout. Partly
    Chased ignition system but that’s goes into a web of dust!

    More fun

    Oh and I was advised there might be low oil pressure and a charged cooling system, dear lord I hope it’s just a gasket job. Trouble is we can’t check until she’s able to start!

    I’m sure this is one of those chasing problems until mostly restored. It’ll have a full restoration with quality components throughout just not in a weekend

    Make a great car!

  8. #8
    Join Date
    Dec 2018
    Location
    Bristol
    Posts
    16
    Oh and there’s no isolation switch. Had a look for that too!!

    Happy I’ve got fuel power feed now. Now just to chase out the other gremlins

  9. #9
    Join Date
    Dec 2018
    Location
    Bristol
    Posts
    16
    Absolutely delighted, today she fired up with lots of big exhaust notes!

    Thanks to Ray ag V8 for supplying a new ignition system.

    Fuel was just a loose cable and she’s roaring away.

    Need to dial in the timing properly, so that’s the next job

    Beaming!

  10. #10
    Join Date
    Jan 2009
    Location
    Dronten, the Netherlands
    Posts
    345
    Quote Originally Posted by rpm015 View Post
    Beware of "just tidying" your wiring it can lead to a world of pain!https://imgur.com/a/aNhBhpz������
    just as not tidying your wiring can lead tova world of pain I suppose, if it is all buggered up and unlogical, I'd bite the bullet and start from scratch.....
    BR, Theo

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