Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14

Thread: fuel consumption revisited

  1. #11
    Join Date
    Sep 2009
    Location
    Sydney
    Posts
    167
    Total Downloaded
    0
    Just remembered seeing a guy with a classic range rover the fuel pressure was way high because the return to the tank was blocked with rust. It may be worth checking your fuel pressure. Spec is most likely 200 to 250 Kpa. Just a thought.

  2. #12
    Join Date
    May 2018
    Location
    Geelong
    Posts
    28
    Total Downloaded
    0

    On the right track

    Sounds like you are on the right track. Too little advance will kill economy and power, especially since as you have already noted the dizzy does not allow much mechanical advance. On my 3.9 i run 12 degrees BTDC initial, to get the total somewhere in the range of 20 to 25 degrees. Realistically this isn't enough total, but I don't want any more initial timing so until I get around to tuning the dizzy with different springs etc. it will do. Working vacuum advance should help highway economy a lot too.

    Bosch ignition module is a good upgrade, even if just for the reliability.

    Injector upgrade to later model Bosch 4 hole certainly smoothed out my idle,it gave me a slight bump in economy, but not enough to justify the cost IMO, unless you needed new injectors anyway.
    I didn't notice any increase in power, at full throttle the "garden hose" Lucas injector is not that big of a deal, atomisation helps emissions and economy, for power you just need bulk fuel (not strictly scientifically true, but with an ancient engine design it really doesn't matter).

    See video below for comparison of Lucas Vs Bosch Injector.
    Shared album - Alex Redsell - Google Photos

    Note: The Bosch injectors I used were reconditioned units from a 5 cylinder turbo Volvo. They have the same specs as the 4.6 Mustang injectors that most use, but have the correct slot at the top making them a direct swap into the Landy fuel rail.

    Definitely check your fuel pressure too, my return line inside the tank was blocked causing 50 to 60 psi of fuel pressure (spec is 34 - 37 PSI). I chucked up an old speedo cable in a drill and used that to clear the blockage (I frayed the end of the cable a bit like a wire brush).

    All of this and I average around 19 to 20 L/100 km in my Rangie (3.9 auto, 32X11.5 Muddies, 2 inch suspension and 1 inch body lift, heavy bar work and winch)
    I can get 17 to 18 L/100 km if I use 235/85 R 16 all terrains, so a skinny tire certainly helps. But mine is just a weekend toy and I usually find myself in muddy terrain so I tend to leave the muddies on.

  3. #13
    Join Date
    Feb 2020
    Location
    Perth. Western Australia
    Posts
    172
    Total Downloaded
    0

    Smile

    Firstly, thanks to all, the list of things to do is growing.
    The Bosch injectors I used were reconditioned units from a 5 cylinder turbo Volvo
    Any chance a part number, so if needed I can be sure of correct ones? found a few posts on the Bosch injectors, but most too old and the links to buy are not working anymore. (old ebay ).

    So another stinking hot day in Perth today, 38deg, but I have the dissy out, had to cut rotor off with dremel. What a mess, seems someone previously had a stuck rotor and sprayed oil, grease or something to try and free, then broke off rotor and left bits inside, just burnt black gunk with lots of black plastic bits everywhere. mechanical advance barely moving as suspected. All cleaned up and now smooth movement. New o rings in case the oil is from shaft. Will install when weather cools a bit.

    Question:
    On my 3.9 i run 12 degrees BTDC initial
    Just to be clear, is this with vacuum advance connected or not?, manual say's 2 deg btdc with disconnected, as it all wasn't working before, what can I expect with it connected.

    Interestingly, while dissy out of the way, I removed the temp sensor (2 wire) and tested in cup of boiling water, ie. 100deg, reading was 750ohms, I'm guessing they get a lot hotter when engine turned off after running. They are not too expensive so I will get new one and do similar test and compare before fitting.

    It's a pain to have to go through all this, but even 20liters per 100klms is poor economy, but I can live with that. The more I drive it the more I like it. That's the confusing part, it runs really well, a joy to drive.
    will update soon.
    cheers.
    Ron.

  4. #14
    Join Date
    Feb 2020
    Location
    Perth. Western Australia
    Posts
    172
    Total Downloaded
    0

    update

    An update,
    dissy installed and 'correct' timing done. Bought some new hose as well.

    Here's what I discovered; white paint mark on crank pulley, Wrongly assumed this was correct for base timing, got under vehicle and cleaned it up.
    White mark was very roughly on the wrong side of TDC, so without advance it was firing after TDC.
    All cleaned and remarked the T and also 6 deg and 12 deg. I'm going to experiment with different timings.
    1.Have set it to 9 deg initial, WITH the now working vacuum connected. as a start.
    2.fit new hose.
    3. decided to replace other similar hoses which included fuel pressure regulator. and sure enough, it was split where it connects to plenum.
    I had removed the FPR end, and used clear hose to do suck test, so assumed it was good.
    OK, good, that's 2 things, BUT, when starting, it sounded different, it was quieter and smoother, a different exhaust note?? That got me thinking, was it really running on all cylinders before? So, into the bin to pull out old spark plugs, and using the motorcycle, (easier by myself) I tested all plugs.....well....2 of the old plugs not firing....

    That's 3 things, enough she cried, time for testing. same method, same journey, Unbelievable!

    94 klms on 20 liters of fuel. That's a huge difference, (53 previous), I'm a happy man, well, still not great but hey.

    I will continue and test other things, just to say to anyone new to this, Assume nothing. fully test everything.

    Thanks to every one here, would not be possible without all the great help and advise on this site.
    stay tuned.

Page 2 of 2 FirstFirst 12

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Search AULRO.com ONLY!
Search All the Web!