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  • Air problems.

    Hey guys,

    Just wondering if anyone has experienced this issue before or has any idea of what may be happening and why.
    I've recently developed a problem in my fuel line with some kind of air leak. I was just up in Maleny when the car started sputtering as it would when running out of fuel, at the time I had one tank (rear) with bio and one tank (front) with SVO and was running on the SVO. As soon as it started to happen I switched to the bio and kept the revs up and the problem subsided. I then continued to drive on to Byron Bay and on the way switched back to SVO. After around 50-100k's the problem started happening again. Along the freeway I was only able to travel a few hundred meters before having to pull to the side and re prime the IP to get her going again. At this point I was out of bio and managed to pull into a servo to put in enough diesel to get me to Byron. During the last 100 odd k's I was switching between the diesel and SVO (to save the small amount of diesel I'd put in for start up next day) and she seemed to be running fine again on the SVO.
    After draining the tank of diesel I have been running SVO for the last day or so probably traveling 100k's on SVO (slight blend now with about 5 litres of E-10 into 80L) without any problems until tonight. I was just pulling out of town to go see a friend when the same sputtering started to happen, this time very quickly she cut out and I pulled to the side of the road. After attempting to prime about 10 times I only managed to move her about 20 metres down the road to a safer place until I could wait for a friend to bring a jerry can of dino. There seemed to be an endless supply of air in the line.
    Now, here's what's strange to me; I put some dino into the rear tank again, primed the SVO as best I could (lots of air in the line and only small trickles of straight fluid between previous attempted starts), changed the factory 3 way to the dino tank before startup and turned her over. First turn it was a little bit rough for about 5 seconds and then smooth sailing all the way back into town..

    I drive a Troopy, two standard 90L tanks, factory 3 way switching between them, 12mm line from the 3 way to a 30 plate HE, into a CAV and then IP.

    I am thinking that the CAV filter may be getting blocked (about time for a change), however this doesn't really answer how air is getting into the line to me (unless I'm missing something) and also doesn't explain why as soon as I switch tanks she is running fine again and the air problem disappears. From my rough calculations it takes around 15-20 minutes of idle to use all the fuel from the 3 way in the lines until she cuts out so I technically was still driving on veg back into town.

    Extremely tired at the moment so I hope it all makes sense..

    Any ideas?

  • #2
    Re: Air problems.

    Probably leaking air in at the CAV filter. They have lots of seals which need to be perfect, but frequently aren't.
    Johnnojack
    4WD Isuzu Jackaroo 3.1 200000km on WVO,(2020) 2 tank home built system 6 solenoids FPHE, heated filter fuel line and tank pickup for thicker oil. Mk. 9 version now and no changes planned as trouble free.
    Mercedes W201 190D 1986 model: 2 tank system, bigger fuel line from tank, no heat exchanger, electric pump for diesel 22000km so far sigpic

    Comment


    • #3
      Re: Air problems.

      Hi Tweak,

      I suffered through air leaks for years. How do you prime the IP? There is a few usual suspects for air leaks.

      1. The primer diaphragm (if you still have original stock assembly)
      2. The little water drain o-ring under the filter
      3. Fuel lines going soft at junctions, bends etc

      It sounds like the thicker fuel is creating too much vacuum, and causing an air leak that doesn't exist on the thinner dino or bio blends.

      Fixes:

      1. Chase the air leaks with gusto.
      2. Run thinner blends.
      3. Fit a pusher pump (tick tick kind)
      4. Replace filter primer assembly.

      It's not for everyone, but a pusher pump will significantly assist with persistent difficult to solve air leaks. I suggest you find the root cause first. Fitting clear nylon hose lines will help you find the leaks. They will last for months, so they can stay on for a good length time allowing you to diagnose and fault ind properly.

      Good luck!

      Comment


      • #4
        Re: Air problems.

        Blocked Breather on Veggie tank.
        Some gunk (Glad Wrap??) in veggie tank which sometimes blocks the pickup, but moves away when using other tank, then gets caught up again?
        Some gunk in the fuel line which is in a section of hose between fuel pipes. Sometimes it blocks the downstream pipe. I had this and had to blow air down the line from a compressor to get rid of it.
        That's all I can think of.
        Tony
        Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

        Current Vehicles in stable:
        '06 Musso Sports 4X4 Manual Crew Cab tray back.
        '04 Rexton 4X4 Automatic SUV
        '2014 Toyota Prius (on ULP) - Wife's car

        Previous Vehicles:
        '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup.
        '80 Mercedes 300D. 2 tank conversion [Sold]
        '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Engine donor for W123 coupe. (body parted out and carcass sold for scrap.)
        '85 Mercedes Benz W123 300CD Turbodiesel
        '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
        '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
        '06 Musso Sports Crew Cab well body. [Head gasket blew!]
        '04 Rexton SUV 2.9L Turbodiesel same as Musso - Our Family car.
        '06 Musso sports Crew Cab Trayback - My hack (no air cond, no heater).

        Searching the Biofuels Forum using Google
        Adding images and/or documents to your posts

        Comment


        • #5
          Re: Air problems.

          Thanks guys, looks like I have a few things to look at.

          The primer is the stock IP with a manual pump, though it is an aftermarket Bosch. There is a brass washer and rubber O ring which I added straight after the conversion as priming was causing a leak around the seal. There doesn't seem to be any oil leaking around the O-ring, however it also doesn't feel like it's doing it's job (after lots of pumping it still won't stiffen).

          I'm heading to a shop to grab a replacement CAV filter element today and will check all the o-rings. Can you get over the shelf replacements, viton?

          Tony - I have suspected something with the tank pickup. When it was first converted a couple months ago I would sometimes lose power on the front tank even when running SVO in both of them. Changing tanks briefly seemed to fix the problem so I have had a feeling that perhaps some gunk is causing a block. It will be a PITA if that is the case as I don't really have the facilities to drop the tank until I get back to Melbourne.

          Will have a play around and let you guys know the conclusion!

          Comment


          • #6
            Re: Air problems.

            Re the CAV. It's not the material of the CAV that's the problem, it's usually a fleshware problem.. I.e. the user not putting the seals in the right place. They are not all the same size, and must be fitted correctly. I'm with JJ and would look at the CAV first, in particular if your primer pump won't get firm.

            What engine have you got?
            What model troopy?

            Toyotas have an in tank pickup that can block. Blow back with air will give temporary respite.

            If you have a 2H, then check the gauze filter on the inlet to the lift pump.

            But first, reassemble that CAV taking great care to get the seals correct.


            Tim
            Toyota Landcruiser 1988 HJ61 Manual Wagon
            12H-T turbo Direct Injection.
            Twin Tank setup runs on 100% WVO after warm up. 30 plate FPHE with 80C output, 12mm fuel lines
            Start up and shut down electric fuel pump feeds IP direct.
            Front 4WDSytstems Lokka, Rear ARB airlokka for quick escapes up sandhills. Performance GTurbo with 600mm FMIC gives 450nm @ 1700rpm at 20psi boost.

            Comment


            • #7
              Re: Air problems.

              Tim - It is an '88 2H. I haven't removed the CAV filter since the change so they should all be seated correctly, however it will be the first thing I check.

              I haven't yet gotten to know the IP too well, would you mind explaining the whereabouts of the gauze filter?

              Thanks,

              Shane

              Comment


              • #8
                Re: Air problems.

                from experience,
                A blocked fuel filter can look like air in the line.

                Comment


                • #9
                  Re: Air problems.

                  These IP's will suck like crazy. if there is a restruiction to flow like a blocked / partially blocked filter or pickup, they will draw air through a weak spot like the hose clamps at filter barbs, which ofcourse can be intermittant and sporadic. clear nylon hose lines will tell you lots.

                  Comment


                  • #10
                    Re: Air problems.

                    Shane,

                    The lift pump is attached to the side of the injection pump.
                    One component of the lift pump is the primer plunger. If it the original type that you unscrew, then pump, then screw the plunger down again, then they are a potential air leak problem.

                    The lift pump provides the required internal pressure for the injection pump to work properly.

                    On the inlet to the lift pump is a banjo fitting that joins the rubber hose from the tank. Inside that banjo fitting is a gauze filter.

                    I agree with Craig's observations above, although the IP itself doesn't suck, it's the lift pump that does the sucking and pushes the fuel through the standard filter into the injection pump.

                    I also agree with Tilly and the strong suction of the lift pump can draw air from the fuel (never quite understood how this happens, but it does) if you have a blocked filter on the suction side, or too small fuel lines for thicker winter oil, or a blocked pickup in the tank.

                    Change your filters,
                    Ensure your supply lines are big enough, standard is not big enough for cold veggie oil,
                    Remove the in tank filter and replace it with a coarse prefilter you can service outside the tank.

                    Tim
                    Tim-HJ61
                    Donating Member
                    Last edited by Tim-HJ61; 13 July 2013, 09:15 PM. Reason: typo
                    Toyota Landcruiser 1988 HJ61 Manual Wagon
                    12H-T turbo Direct Injection.
                    Twin Tank setup runs on 100% WVO after warm up. 30 plate FPHE with 80C output, 12mm fuel lines
                    Start up and shut down electric fuel pump feeds IP direct.
                    Front 4WDSytstems Lokka, Rear ARB airlokka for quick escapes up sandhills. Performance GTurbo with 600mm FMIC gives 450nm @ 1700rpm at 20psi boost.

                    Comment


                    • #11
                      Re: Air problems.

                      As tim says the banjo fitting, the filter up top with the bleeder, and don't forget the water sediment trap under the car halfway, all of mine have had a build up of glycerine dropout block them in the early days but that aint happened for years now good luck you will sort it and it will go for ever.

                      Comment


                      • #12
                        Re: Air problems.

                        OK, so I replaced the CAV filter and it is running better however there is still a resistance once the SVO has been on for a period of time. I am highly suspecting the pickup in the tank as the moment I change to the rear tank you can feel the pressure release and the problem subsides.

                        All lines are 12mm goss fuel line and the stock sedimentary filter has been removed. I will look at replacing the lines again with clear when I am garaged once more. As previously mentioned the primer plunger is a Bosch unit with brass washer and added rubber o-ring. After excessive priming the o-ring seal has started to fail again and a small amount of fuel will leak. I do not have the money at the moment to replace the unit on the road (80-90 odd in stores compared to 30 online), however once the fuel is primed and motor is running leaks cease to be an issue. I won't rule out that once the blockage in the line is creating pressure that air isn't being drawn through there, however.
                        Tomorrow I can go and get another replacement o-ring and check the gauze filter on the Banjo, thank you Tim for that information.

                        Does anyone have any experience removing the pickup from the tank? Does the tank have to be dropped?

                        Comment


                        • #13
                          Re: Air problems.

                          Originally posted by tweak View Post
                          Does anyone have any experience removing the pickup from the tank? Does the tank have to be dropped?
                          I believe so. On the 60 series wagon which I have, the tank needs to be dropped to access the fuel pickup. The fuel level sensor can be accessed from a plate in the rear wagon section. The Troopy of the same era 'may' have two plates over the tank. I guess you are really loaded up and this will be a pain.

                          There is a temporary fix that might work, which is to blow air backwards down the line into the tank. It might clear enough of the gunge if that is what is causing your problems.

                          Check also the rubbery fuel hose that joins the tank to the steel fuel line. They deteriorate over time. Hard to see and get at, but that could be a spot for sucking air too.

                          The 12ht motor in the 60 series chassis has a return line to the fuel tank. This fuel line is open ended. I doubt you have the same, but IF your model has a second outlet on the tank where the fuel hose outlet is, try swapping them over so you are drawing from the blanked off return line. This is a long shot. But either way, blowing air back into the tank may clear stuff off the filter if that is the problem. This is what you are looking for to remove. See how fine the gauze is, good for diesel, not so good for our fuels where there can be a bit of fat blocking things up, or gunge buildup.




                          Tim
                          Toyota Landcruiser 1988 HJ61 Manual Wagon
                          12H-T turbo Direct Injection.
                          Twin Tank setup runs on 100% WVO after warm up. 30 plate FPHE with 80C output, 12mm fuel lines
                          Start up and shut down electric fuel pump feeds IP direct.
                          Front 4WDSytstems Lokka, Rear ARB airlokka for quick escapes up sandhills. Performance GTurbo with 600mm FMIC gives 450nm @ 1700rpm at 20psi boost.

                          Comment


                          • #14
                            Re: Air problems.

                            To be honest, Toyota, using a fine gauze filter like that in the tank with such difficult access is mental.
                            Surely rational people would agree that if they must put a screen in there you would only need to screen out particles a little less than half the size of the 5/16 lines used (very course)?

                            Comment


                            • #15
                              Re: Air problems.

                              Originally posted by tweak View Post
                              As previously mentioned the primer plunger is a Bosch unit with brass washer and added rubber o-ring. After excessive priming the o-ring seal has started to fail again and a small amount of fuel will leak. I do not have the money at the moment to replace the unit on the road (80-90 odd in stores compared to 30 online)
                              Could maybe get one delivered ($25)?

                              Diesel Hand Primer Button Type Toyota Nissan Isuzu | eBay
                              83Patrol
                              Donating Member
                              Last edited by 83Patrol; 21 July 2013, 07:41 PM. Reason: more info
                              1987 Mercedes W124 300D
                              1997 Ssangyong Musso Wagon

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