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Another LPG Backfire

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  • Another LPG Backfire

    Well its happened again. Comming home from the shops with the Mrs and the kiddies the pajero backfired again ah the joys of LPG. Some may remember i had this problem couple of months back. Dealer was quite happy to point the finger to plugs and leads. Mind you they rechecked everything first time around at my expense.
    Anyway i rang the dealer and same old story might be the plugs might be the leads or my ignition system.
    This time around more damage occured.
    Took out the afm again honeycomb was shrivelled up sitting on the airfilter.
    Broke the lower section of the airbox.
    Broke the middle piece of the snorkle where it clips in.
    Blew the gasket out of the mixer.
    Vehicle was just about undrivable on both fuels after this.
    After ringing dealer they were assuming the backfire was related to above items and manifold will have to come off. I said fine but who pays to sort it out? Couldnt get a straight answer.
    I said leave it with me i will get back to you.
    The way the vehicle was running it would have to be towed back to the dealership / installer it was running quite rough after this incident.

    Lucky me has to go to work tommorow so it was too late in the day to get it back to the dealer said to myself i have to at least get it running on petrol and sort out the rest on Monday. Plus after i rang the tech second time around he had already left for the day.

    First thing i did was detatch the airbox then induction pipe.
    When i removed induction pipe upon examination i saw a cut in the pipe where the clamp is positioned. Refer to my pics.
    Based on the position of this cut i am assuming its safe to say that the clamp has cut into it due to engine rocking whilst starting, accelerating and decellerating.
    All have a look at the pics i have provided any input will be greatly appreciated as i will be pushing this back to the dealer/installer to cover costs of all the broken bits.
    I am quite confident this is the cause of the problem just need some reassurance.

  • #2
    Looks like you found it. I can't believe the damage this time. Damn...
    2013 NW 3.2 DiD VRX. EFS Elite HD 2" suspension. Boos Bash plates. Roley rear plate. Ironman bullbar with 1200lb winch and DRL's. 9" LED spots. Dual Battery. Ocam rails and roof rack, Kings 2.5x2.5 awning. Beaudesert exhaust with muffler delete. Safari snorkel. Provent 200 catch can. Single drawer with fridge slide, Evakool 50L fridge. Redarc Elite electric brake controller. EGR turned off and blanked. Idrive. Ultragauge.


    • #3
      I gather the pipe the that is cut is after the AFM? Is it also after the donut/mixer? Unmetered will cause a backfire no doubt so this may be the cause, in-which case you would have a claim.
      2014 NW VRX , Alloy ECB bar, Poly air bags, EGR fixed. EDS scan gauge, lockup mate.
      2003 NP DID GLS retired and gone to a good home
      2007 21' Lotus spirit caravan

      LH Torana


      • #4
        Originally posted by Muzza View Post
        I gather the pipe the that is cut is after the AFM? Is it also after the donut/mixer? Unmetered will cause a backfire no doubt so this may be the cause, in-which case you would have a claim.
        Hi Muzza you are quite correct in regards to the pipe. Should be intresting to see if they accept responsibility for this issue. Some how i think they will wash their hands of it.



        • #5
          We're about to go into battle to have a repair done following backfire. For this to happen to people so often is ridiculous. Installer said, "it's not covered under warranty". We're now going through Office of Fair Trading.

          Conversion was only 3 months old, everything serviced by the book and the installer saw the car 3 times in the 3 months before the backfire- install, install service at 500km, then regular mechanical service a few weeks before backfire.

          Not as bad damage as yours, but just a new air box is >$500, plus dent in bonnet, who knows what else?

          Took it to another LPG installer who said he just sends people who want to convert a Pajero away- "too many problems". Wish I'd known that b4.

          They've got you over a barrel when you need your car ...
          2009 Mitsubishi Pajero NT GL, Diesel, Auto, Rear diff lock, side airbags, 3000kg towpack, Milford cargo barrier, Rhino roof rails+ bars, Teshonka Prodigy brake controller


          • #6
            I will know more on Thursday in regards to mine.
            Well at least my bonnet didnt get injured.
            I sent the dealer the pics i posted and basically the pictures dont mean anything to him. All care no responsibility. So far it doesnt look promising. I'm 80% sure they will try and finger my vehicle as the problem even though its quite obvious the clamp has cut into the induction pipe in my case. We shall see.
            I will persue this further if i dont get the results i'm after i stated this in my email and obviously didnt like what was in it received a prompt phone call pretty much that afternoon.
            I will post an update once i have some further news.
            Good luck with your battle. Hopefully it gets sorted.


            • #7
              Well we had a meeting with the service manager and the tech.
              Bottom line the only thing they will cover are the lpg components if they are found to be faulty.
              They are happy to pull my vehcile to bits to try and establish the root cause eg plugs leads or anything else at my cost.

              The only choices i have are as follows:

              Let them rip it apart to see if there are issues with coils plugs leads or what ever else they see necessary to establish the cause. Estimated labour for pull down and diagnosis is apx 5 hours worth. Plus what ever other parts are required on top of that payment for the broken bits and any new bits they wish to install. (My cost)
              Or do nothing sort it myself.

              If they do find an issue with the lpg system they will cover the cost of the repairs.

              In regards to the tear of the induction pipe because its not behind the LPG mixer they beleive it wont backfire. I disagree because you still have to factor in the Airflow meter which sends back signals to the ECU in relation to the barometric sensor which fidles with the timming and possibly other adjustments.

              This backfire could potentially cost me between 1000 to 1800 dollars to sort it if i let the dealer / installer look at it.

              What would you do in this situation?

              I feel its quite easy for any installer to pass the blame onto the vehicle and get out of rectifying the issue at hand.

              Something to think about for people who are thinking about going down the LPG route.

              Stuck between a rock and a hard place i have apx 1 week to decide if i let them sort it possibly at my cost or i seek an alternative solution.

              Any tips would be appreciated.



              • #8
                Cut my losses, sell the system in an attempt to recoup some of my costs and forgo the gas idea or fork out more cash with the aim of trying to break even and install an injected system.

                If you persevere with wat you have, you within reason have no other option but to pay for someone to investigate the issue for you - or chance another backfire.


                • #9
                  Im going to have another crack at it tommorow. Manifold off fresh set of plugs will try another set of leads as well. Lucky me had another backfire tonight the lower section of the snorkle ended up in the pulley assembley. Damn it.
                  It's really starting to piss me right off now. But i will solve it one way or another. At least the bonnet survived once again.



                  • #10
                    Plugs and leads were done today. Lets see how we go now. Patched up all the plastic bits that got broken i have tied down the airbox for the moment. If all is well i will replace the broken bits in the near future. Time will tell.



                    • #11

                      Before I forked out for stainless leads and good quality plugs (funnily enough the distributor of my lpg system only uses Ford plugs) I was always having backfires in my commodore. After the leads and ford plugs no probs.

                      On the side of my lpg mixer is 2 connections for the gas to go out to the inlet manifold. Only 1 is used. The other is covered with what looks to be a rubber stopper that one would find on a chair leg. One of my early back fires blew this off and this caused the vehicle to run too lean on gas so that it would not run at all. Maybe this is something you could check.


                      • #12
                        wrexed03, that's rubbish. This is the Office of Fair Trading website in Victoria. I'm not sure if they can help:

                        Ours is an Airod system.

                        So far, the repairer has offered to make up a backfire valve for the system, previously quoted as about $60-. New airbox alone is about $500 installed, so that's not a lot of help. Said we'll take it to the next level then and they're going to get back to us on that.

                        I don't whether it's the install, design, whatever because we actually did all the pre-installation stuff the installer recommended. NOW they suggest taking it to the auto electrician to have more gear checked (coils, leads etc.). Rubbish!!!!!
                        2009 Mitsubishi Pajero NT GL, Diesel, Auto, Rear diff lock, side airbags, 3000kg towpack, Milford cargo barrier, Rhino roof rails+ bars, Teshonka Prodigy brake controller


                        • #13
                          Yep i got the same as you could be this could be that and so on and so on. Unfortunatley stuck between a rock and a hard place.
                          Im not really prepared to throw more cash at the installers to diagnose the problem if any. They could easily finger the car it's self.
                          I have replaced the leads and plugs once again but the backfire isnt frequent enough to prove any of those items are at fault.
                          I did the right thing prior to conversion leads and plugs as advised.
                          It's too easy for the installer to get out of it. The dollars i spend sorting it i prefer to go injected and not worry about it anymore.
                          I have a mate who can buy the parts for the vehicle at trade for me which will also save me some dollars and put them on once i am comfortable the problem has been eliminated or the system has been replaced with the later(injected).
                          We shall see. I look forward with intrest how you go with your issue.
                          Best Regards


                          • #14
                            Interested to see what plugs you put in, Repco have a plug for the NM specifically for LPG.
                            NGK PFR6J-11
                            Also found this thread
                            NX Pampas Cat GLS MY16
                            Member 1228 Pajero Club


                            • #15
                              Initially i was running the genuine items from mitsu. Platinums. Now im running these as a temporary measure with a 1.0mm gap on each ZFR5J-11 the box also has a number 5584 these are NGK i believe copper tip not the sharp ones like the platinums. So far so good but time will tell. This is a temporary measure for now to see if problem re occurs. Takes me apx 2.5 -3 hours now to remove and re fit the manifold plugs and leads i'm turning pro now lol. At least i know it's done properly.



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