Ad below navbar

Collapse

Announcement

Collapse
No announcement yet.

High Fuel Consumption Conundrum?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • High Fuel Consumption Conundrum?

    I've noted a much higher fuel consumption when touring recently. Interestingly it seems to be associated with highway driving but only if the speeds average over 100kph.

    I would normally expect between 500 and 550 km to a tank before the low fuel light and another 50km from there. City driving I've got the consumption at about 13L/100km. The day we did Cape Range - Exmouth - Kalbarri, some 850km I calculated 19.5L/100 . Bloody hell, got real concerned after turning off the highway to head toward Kalbarri through the National Park. The low fuel light started to present itself after 430km. I dropped my speed to 80kph and coasted down hills (of which this opportunity presented itself only twice ). 8L remained in the tank which if I maintained the 110kph would have been real tight.

    The next day I took very easy. nothing above 100kph and let the speed wash off up hills, slow acceleration etc... 17.5L/100km.

    Factors:
    • Very hot on the 850km leg - probably 50+*C over the road but dry
    • Heavy car
    • Crap on the roof - of course now we're heading home I used the 40L carried on the roof (which would have been handy on the way to Kalbarri) so a little lighter and repacked to be slightly more aerodynamic
    • 110kph but fairly constant for hours
    • Windy but not necessarily a head wind
    • RON91 fuel @ Exmouth and Minilya - quality should be ok and both high volume sales
    • Tyre pressures - I may have dropped the ball here. After crossing Yardie Creek from Ningaloo where px was set at 16/18PSI I inflated to 30/32PSI. It was scorchingly hot and the pressures were set in these conditions. For some reason I never rechecked the pressures the following morning. In fact I didn't recheck the pressures until after returning to Perth. They came in at 25/26PSI cold.
    • O2 sensor changed before the trip
    • Dizzy, all plugs and leads changed before trip and timing adjusted
    • Air filter was relatively new before trip. I did shake excess dust out of it before the return drive from Cape Range NP

    Even given the above factors should the burn be so high?

    I didn't get a chance to clean the MAF before going. I know it doesn't take much but I was real pressed for time in the months before the trip and since it was working I didn't want to risk stuffing it during the trip.

    I have since also changed the engine coolant temp sensor but I believe the old one was within FSM spec.

    The ~2000km trip down to Margaret river and across to Wave rock the week before averaged 15-16L/100km with the same load bar the 2 jerry cans.

    I can accept that there is probably not a smoking gun solution but there seems to be quite a disparity comparing consumption between the two trips. Did those tyre pressures really cost me that much?
    NX GLS MY16 Auto: MM Towbar | Spare Lift Kit | Cooper ST MAXX 265/65R17 | SPVi Module mk3.1 | Autosafe Half Cargo Barrier | Torque Pro App | Donaldson 3um 2ndry Fuel Filter | Diff Breathers | GME4500 UHF | Rhino Rack Pioneer Platform | Roley's Rear Bash Plate | Bushskinz Underbody Protection | Airtec Snorkel | Onboard Compressor | Awning | ARB Deluxe Bar | Lightbar | Sherpa4x4 Winch | Bushskinz Sidesteps | Masten TPMS

    Build Thread

  • #2
    The use of ron91 vs ron95 is a factor. Having a heavier loaded vehicle is another more so with a petrol vs diesel . Stuff on roof makes a un aerodynamic vehicle even more aerodynamic too
    NS SWB X 3.2DiD - Factory locker, Hella spotties, GME UHF, roof racks otherwise stock as a rock.

    Retired: 1991 NH SWB 3.0L V6 5sp Manual, Mickey Thompson ATZs, GME UHF TX3200.
    Wanting: Rocksliders, 2" lift, snorkel or perhaps I should wait and purchase a NS swb in 12months time.

    Comment


    • #3
      sounds about right really, a bit of tweaking on the tyres may have helped but hey if it makes you feel better, I get 16.5-18l/100k around town
      If I agreed with you, then we would both be wrong

      '89 NG Paj, 3L V6, now running 2" suspension lift, 33" Micky T Baja Claws's, Front LOKKA & 12,000lb winch

      Comment


      • #4
        I find that speed is a massive factor with mine.
        see below.

        http://www2.pajeroclub.com.au/forum/...463#post289463

        but you also had type pressure, roof load, aircon running, extreme temperatures etc, all adding up as well
        99 NL Exceed Manual, TJM Alloy bar, 33" Summit Mud Hogs, 7" HID spots, 18" LED Lightbar, Uniden UH7760, snorkel, 13,000lb rope winch.
        Rear telescopic LED light and Hi Lift Jack, 3 X 2.5M awning, Treds.

        Comment


        • #5
          hmmmmmmm my 3.0 petrol NH is a thirsty beech im currently getting about 240klm per 50 litres around town its a auto as well prob not as economic as a manual

          only use the expensive fuel as well

          I have done the 02 sensor air filters leads coil plugs oil and filters fuel filter gave the injectors a clean new seals & orings seems to run smooth what have I missed ?

          or what would I be looking at next

          cleaning the injectors did not make any difference to the fuel economy but does run smoother if that makes sense

          car is still a work in progress

          Dave

          Comment


          • #6
            Tyre pressure wil have big impact on fuel eco..

            Reading this cements my reasoning for geting a diesel.

            Not having to much of a dig but it always amuses me when ppl buy big heavy 4x4, suv or van and get a petrol engine then ask why it uses so much fuel.
            .

            Comment


            • #7
              Originally posted by chriso of penrith View Post
              Tyre pressure wil have big impact on fuel eco..

              Reading this cements my reasoning for geting a diesel.

              Not having to much of a dig but it always amuses me when ppl buy big heavy 4x4, suv or van and get a petrol engine then ask why it uses so much fuel.
              My specific question was more aimed at why is it using so much more fuel than normal. 7L/100km seems quite a large variance. 13L/100km is to me already a high enough consumption for an engine that only puts out 110KW out of the factory. I have a 2.0L turbo golf giving me ~160KW (chipped) at around 8L/100km and when the light goes green I go.

              @dave05
              I did run a can of injector cleaner through it a little while back and although didn't noticeably alter the burn it did run smoother, so I know what you mean.

              @shambles
              Interesting. I don't know if "comforting" is the right word to use but your experience tends to lend weight to my thoughts regarding burn vs speed.

              @bakerboy
              A little but are you running 33 M/T's or do you attribute the extra usage to something else?

              I was running RON95 basically until the start of this trip partly due to a couple of posts saying don't bother with anything other than RON91. Even if I wanted 95 it wasn't always available. Also there is the price point - first fill out of Perth and the price is already well up ~25c/L. Was paying on average $1.70/L for 91. Saw 98 for $2.04. I think I was more surprised that 98 was even being sold rather than the price. Probably because after paying $1.74/L it was already uncomfortable to sit down.

              I just cleaned the MAF this afternoon and replaced the air filter again. I've also got a new fuel filter to go in when I get a chance.
              NX GLS MY16 Auto: MM Towbar | Spare Lift Kit | Cooper ST MAXX 265/65R17 | SPVi Module mk3.1 | Autosafe Half Cargo Barrier | Torque Pro App | Donaldson 3um 2ndry Fuel Filter | Diff Breathers | GME4500 UHF | Rhino Rack Pioneer Platform | Roley's Rear Bash Plate | Bushskinz Underbody Protection | Airtec Snorkel | Onboard Compressor | Awning | ARB Deluxe Bar | Lightbar | Sherpa4x4 Winch | Bushskinz Sidesteps | Masten TPMS

              Build Thread

              Comment


              • #8
                You are simply driving to fast! to expect any differant, have to much stuff on the roof, and tryre pressures did not help either.

                Run at 80 KPH
                Tyre pressures 40 +
                And maybe tow a light trailer instead of roof racks.

                I use to fly Air craft and drag friction / Wind has a high a impact on economy.

                I you double the speed in an Air craft you need to quadripple the power to do so. So Back of the peddle! enjoy the scenery, save money and wear and tear, simple as that!

                Cheers.

                Comment


                • #9
                  I remember hearing somewhere that once you get the rpms over 3K your fuel economy really starts to suffer. This limits me to around 100km/hr but with a fully loaded vehicle I didn't like to go much over 90-95. But having said that, I still get better economy when my Paj is fully loaded ( including the roof rack) on the hiway than I do around town with nothing in the vehicle or in the rack.
                  2011 NT GL | ARB Bull bar. LED Spotlights/Lightbar. 2inch Lift Kit. GME aerial. GME uhf radio. SPV egr blank. Roof rack. ECU remap. 3inch exhaust. Tow bar with anderson plug. Bash plates. K&N Filter. Xtreme Heavy Duty clutch. Side awning. Dual battery. LED low beams. Front and rear sway bar adjustable link kits from Superpro. Jonny Tig aftermarket front mounted intercooler upgrade. Heavy duty synthetic winch. E lockers. Dual fuel tank. Polaris with HEMA maps. Cargo barrier.

                  Comment


                  • #10
                    I can honestly say that low tyre pressures cause a big hike in fuel usage, mine at 28psi instead of 36psi put me into low 16's instead of mid 13's as per normal. Was very comfortable but cost heaps on the big trips.

                    Also, don't go exceeding the tyre pressure max rating on the side. I did that unkowingly and ended up blowing a bubble out the side wall on the front. Had them at 42psi instead of 36psi and only took about a month for the tyre to get the bubble.

                    I get really poor eco from 91 and E10, 95 is the sweet spot for me. 98 makes no difference over 95 so I don't bother paying extra.
                    97' NK 3ltr GLX LWB Manual | 3" lift | Wildcat headers | K&N air filter | 2.8 crawl gears | 4Terrain clutch | 2.25" exhaust | Factory locker rear | TJM 10,000lb winch | TJM snorkel
                    97' NL GLS LWB Auto | 6G75 3.8ltr | Redback Headers

                    Comment


                    • #11
                      Originally posted by chriso of penrith View Post
                      Tyre pressure wil have big impact on fuel eco..

                      Reading this cements my reasoning for geting a diesel.

                      Not having to much of a dig but it always amuses me when ppl buy big heavy 4x4, suv or van and get a petrol engine then ask why it uses so much fuel.
                      I new it would chew fuel however was just wondering what the general fuel usage would be and if any one can point out how much more my pajero is using in comparison to theirs.

                      and if there are any repairs that can be done on an aging 4wd that could help reduce fuel usage going by the original post mine is getting round 60klm for 12.5 litres if I could make it 100klm id be happier

                      my daughter has a v8 Toyota and it uses less fuel and is heavier than my spadger

                      Comment


                      • #12
                        Originally posted by Paintchips View Post
                        I remember hearing somewhere that once you get the rpms over 3K your fuel economy really starts to suffer. This limits me to around 100km/hr but with a fully loaded vehicle I didn't like to go much over 90-95. But having said that, I still get better economy when my Paj is fully loaded ( including the roof rack) on the hiway than I do around town with nothing in the vehicle or in the rack.
                        Interesting as a couple of us are the other way around. What figures are you getting?
                        NX GLS MY16 Auto: MM Towbar | Spare Lift Kit | Cooper ST MAXX 265/65R17 | SPVi Module mk3.1 | Autosafe Half Cargo Barrier | Torque Pro App | Donaldson 3um 2ndry Fuel Filter | Diff Breathers | GME4500 UHF | Rhino Rack Pioneer Platform | Roley's Rear Bash Plate | Bushskinz Underbody Protection | Airtec Snorkel | Onboard Compressor | Awning | ARB Deluxe Bar | Lightbar | Sherpa4x4 Winch | Bushskinz Sidesteps | Masten TPMS

                        Build Thread

                        Comment


                        • #13
                          Originally posted by Pauly Faulkner View Post
                          I can honestly say that low tyre pressures cause a big hike in fuel usage, mine at 28psi instead of 36psi put me into low 16's instead of mid 13's as per normal. Was very comfortable but cost heaps on the big trips.

                          Also, don't go exceeding the tyre pressure max rating on the side. I did that unkowingly and ended up blowing a bubble out the side wall on the front. Had them at 42psi instead of 36psi and only took about a month for the tyre to get the bubble.

                          I get really poor eco from 91 and E10, 95 is the sweet spot for me. 98 makes no difference over 95 so I don't bother paying extra.
                          I take it that the limit is with reference to cold tyres? So if I had been driving in the heat of the day and the tyres are hot and I'm pumping hot air further heated by the compressor and say set the max of 40psi and continued driving where due to even further heating the pressures sat above the limit would this be an issue, ie is the sidewall rating an absolute?
                          NX GLS MY16 Auto: MM Towbar | Spare Lift Kit | Cooper ST MAXX 265/65R17 | SPVi Module mk3.1 | Autosafe Half Cargo Barrier | Torque Pro App | Donaldson 3um 2ndry Fuel Filter | Diff Breathers | GME4500 UHF | Rhino Rack Pioneer Platform | Roley's Rear Bash Plate | Bushskinz Underbody Protection | Airtec Snorkel | Onboard Compressor | Awning | ARB Deluxe Bar | Lightbar | Sherpa4x4 Winch | Bushskinz Sidesteps | Masten TPMS

                          Build Thread

                          Comment


                          • #14
                            Originally posted by Pajshomoneroguntero View Post
                            Interesting as a couple of us are the other way around. What figures are you getting?

                            I get around 16L/100k on the highway fully loaded. 17-19L/100k around town unloaded. Can't tell you what I would get on the highway unloaded as I've never traveled exclusively on the highway without being loaded up.
                            2011 NT GL | ARB Bull bar. LED Spotlights/Lightbar. 2inch Lift Kit. GME aerial. GME uhf radio. SPV egr blank. Roof rack. ECU remap. 3inch exhaust. Tow bar with anderson plug. Bash plates. K&N Filter. Xtreme Heavy Duty clutch. Side awning. Dual battery. LED low beams. Front and rear sway bar adjustable link kits from Superpro. Jonny Tig aftermarket front mounted intercooler upgrade. Heavy duty synthetic winch. E lockers. Dual fuel tank. Polaris with HEMA maps. Cargo barrier.

                            Comment


                            • #15
                              No that's cold pressure. The max is cold pressure so obviously the rating allows for the tyre to heat up which if done right is about 4psi increase when hot.
                              When I aired up to 40psi it was cold. I just got confused with the other car we were driving at the time, the tyres were only 2yrs old and still had a good 50% tread on them.
                              97' NK 3ltr GLX LWB Manual | 3" lift | Wildcat headers | K&N air filter | 2.8 crawl gears | 4Terrain clutch | 2.25" exhaust | Factory locker rear | TJM 10,000lb winch | TJM snorkel
                              97' NL GLS LWB Auto | 6G75 3.8ltr | Redback Headers

                              Comment

                              Matched content

                              Collapse
                              Working...
                              X