Below Nav Bar Ad Module

Collapse

3.8 petrol intermittantly stalls at idle when warmed up.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • Having Fun
    Senior Member
    • Jun 2015
    • 373
    • Adelaide

    3.8 petrol intermittantly stalls at idle when warmed up.

    OK, so we've had the chirping noise & replaced the accumulator, then we had the dreaded flashing centre diff light & replaced the bits that needed replacing, then we had the crazing readings on the temp gauge on the dash & fixed that too (those last two completely ruined two holidays!).

    Now the jolly thing has started to stall if left in D at red traffic lights for too long! Then it will only start after an embarrassingly long time with the hazard lights flashing & everyone else trying to negotiate around it.

    No dramas if I'm driving, I'd put it in P & watch the idle speed, then kick it in the guts if the idle speed got too low, but hey, I'm not the one driving it to work in the traffic everyday & my wife forgets to move the stick from D to P at the lights, then tears!

    I'm completely over this car, it's not what I wanted, or expected. But I have to deal with it, so;

    1. It drives like a dream while in traffic, until it is stopped at traffic lights & has to wait with every other car at the lights for a while. No missing, no rough idling, great power, no excessive fuel use. Then it stalls & refuses to re-start for several minutes.
    2. The air filter was replaced last August & is still snow white.
    3. The idle speed is IMO too low. It sits on 550-600RPM when warmed up.
    4. The spark plugs are due for a change, but it starts great from cold, no rough running at all.
    5. The Alternator & battery are showing as fine.
    6. Fuel filter??? Like I say, no other issues any other time, except sitting idling at traffic lights for 4-5mins.

    7. MAF or throttle body??? Surely there would be other symptoms if they are involved?
    8. Exhaust; my experience with blocked exhaust tells me that if it is the problem, it would be hard to start & run like a sack of the proverbial? It isn't & it doesn't.
    9. Injectors?
    10. Fuel pump?


    Thanks for reading, like I said, I'm over it. We're swapping cars in the meanwhile, my wife gets my work Ute & the NP gets to tow my work trailer around.
  • Roofchop
    Member
    • Jul 2018
    • 175
    • Carool, Australia

    #2
    Mine had low idle.


    Changed the temperature sensor for the ECU, fixed! (there are two sensors, one for ECU one for gauge)


    On the 3.5 they are next to each other.


    To determine which is which, with the engine warm, and off (ign on), unplug one and see if the gauge falls to cold.


    If it does the ecu one is the other. if it stays "warm" then you just unplugged the ECU sensor!


    When the sensor is bad, the ECU will set the fueling incorrectly.


    $30ish fix
    Last edited by Roofchop; 16-02-20, 09:04 AM.
    2007 NS 3.8 V6 GLX Auto

    Comment

    • Having Fun
      Senior Member
      • Jun 2015
      • 373
      • Adelaide

      #3
      Originally posted by Roofchop View Post
      Mine had low idle.


      Changed the temperature sensor for the ECU, fixed! (there are two sensors, one for ECU one for gauge)


      On the 3.5 they are next tom each other.


      To determine which is which, with the engine warm, and off (ign on), unplug one and see if the gauge falls to cold.


      If it does the ecu one is the other. if it stays "warm" then you just unplugged the ECU sensor!


      When the sensor is bad, the ECU will set the fueling incorrectly.


      $30ish fix

      Thank you for the suggestion Roofchop, I'll give it a try!
      I've already replaced the sensor that feeds the temp gauge & like the 3.5, the ECU one is right alongside of it - it makes sense that it could be stuffed, as the temp sensor for the gauge had almost completely de-laminated.

      Comment

      • Having Fun
        Senior Member
        • Jun 2015
        • 373
        • Adelaide

        #4
        Well, I bought an ECU coolant temp sensor - I'll put it in in the morning, when the car is stone cold.


        I hope that it works, as my wife is gibbering something about throwing a towel over the headlights so it can't see, then shooting it lol.

        Comment

        • El_Freddo
          Valued Member
          • Nov 2018
          • 675
          • Bridgewater, Vic

          #5
          Originally posted by Having Fun View Post
          I hope that it works, as my wife is gibbering something about throwing a towel over the headlights so it can't see, then shooting it lol.
          It’ll still survive.

          It could be a fuel pump issue too. The fuel pump is under the most load when at idle.

          Does it stall and not start when you’ve got a full tank of fuel? I reckon it’d be less likely - more fuel around it to keep the pump cool. Low tank and no liquid fuel around it to keep the pump cool. It stops, engine stops. Pump doesn’t work until it’s cooled down.

          Makes sense to me. Not an easy task to remedy/investigate.

          How many km on this Paj?

          Cheers

          Bennie
          2005 NP DiD auto. The family bus. Dual batteries, snorkel, one side step, King Springs lift, Koni shocks, rear airman airbags, Provent catch can, 81L LRA tank (awesome!). Other rides: "Ruby Scoo" my lifted L series Subaru and my "Redback" Targa top Brumby - only mods are 5 poster bullbar and nicer dashboard from a coupe

          Comment

          • Having Fun
            Senior Member
            • Jun 2015
            • 373
            • Adelaide

            #6
            Originally posted by El_Freddo View Post
            It’ll still survive.

            It could be a fuel pump issue too. The fuel pump is under the most load when at idle.

            Does it stall and not start when you’ve got a full tank of fuel? I reckon it’d be less likely - more fuel around it to keep the pump cool. Low tank and no liquid fuel around it to keep the pump cool. It stops, engine stops. Pump doesn’t work until it’s cooled down.

            Makes sense to me. Not an easy task to remedy/investigate.

            How many km on this Paj?

            Cheers

            Bennie

            We think alike Bennie! It happened on Tuesday & the tank was around quarter full when it happened, so I asked my wife to fill it & hoped that would change things. It did it again Thursday when she was driving it with a full tank of juice - mate did I cop it over that! My fault apparently! (there were tears involved!)

            Absolutely agree that it makes no sense & is extremely hard to pin point!

            The car has 191K on it. Full dealer service history when we bought it (at 114K) & no signs it had ever been off road before we bought it (it has now though)

            I've driven it around town a fair bit now & I have NO dramas with it whatsoever. But I DO put it in P when I'm stopped at a red light for a while as a precaution.

            The idle jumps up to about 700RPM in Park, from 550-600 in Drive.

            I'll put this ECU coolant temp sensor in tomorrow & see how it goes I guess!

            Comment

            • nj swb
              Resident
              • Jun 2007
              • 7332
              • Adelaide

              #7
              Crank angle sensor?

              If it's deteriorating as it gets hot the output signal may be reaching the point where the ECU no longer recognises it. Once the ECU no longer sees pulses from the crank angle sensor it thinks the engine has stopped, and stops firing injectors and spark. Until the sensor cools down, there are no pulses to tell the ECU that the engine is cranking, so no fuel or spark to restart.

              Once the sensor cools down its output recovers sufficiently for the ECU to recognise the pulses, and normal operation resumes.

              Sitting at the lights in N with the revs up is reducing load on the engine (heat output) and increasing airflow from the fan over (the region of) the sensor - so the sensor doesn't get too hot, and everything continues to work.

              The crank angle sensor either works or it doesn't. No missing, or spluttering - just run or stop.
              NT Platinum. DiD Auto with 265/70R17 ST Maxx, Lift, Lockers, Lockup Mate, Low range reduction, LRA Aux tank, bull bar, winch, lots of touring stuff. Flappy paddles. MMCS is gone!

              Project: NJ SWB. 285/75R16 ST Maxx, 2" OME suspension, 2" body lift, ARB 110, 120l tank, bullbar, scratches, no major dents. Fully engineered in SA. NW DiD & auto in place - a long way to go....

              Scorpro Explorer Box

              Comment

              • Having Fun
                Senior Member
                • Jun 2015
                • 373
                • Adelaide

                #8
                Originally posted by nj swb View Post
                Crank angle sensor?

                If it's deteriorating as it gets hot the output signal may be reaching the point where the ECU no longer recognises it. Once the ECU no longer sees pulses from the crank angle sensor it thinks the engine has stopped, and stops firing injectors and spark. Until the sensor cools down, there are no pulses to tell the ECU that the engine is cranking, so no fuel or spark to restart.

                Once the sensor cools down its output recovers sufficiently for the ECU to recognise the pulses, and normal operation resumes.

                Sitting at the lights in N with the revs up is reducing load on the engine (heat output) and increasing airflow from the fan over (the region of) the sensor - so the sensor doesn't get too hot, and everything continues to work.

                The crank angle sensor either works or it doesn't. No missing, or spluttering - just run or stop.

                You could be onto something. I'll try the ECU coolant temp sensor in the morning & if no joy, I'll try a crank angle sensor.


                Thanks!

                Comment

                • Having Fun
                  Senior Member
                  • Jun 2015
                  • 373
                  • Adelaide

                  #9
                  Well changing the ECU coolant temp sensor seems to have done the job (I have literally everything crossed lol)


                  I took it for a spin after I swapped them over & once warmed up, I did manage to get it to stall in D after idling on a side street for about 3-4mins. But it started straight up, first turn of the key afterwards.


                  So, took it home, unhooked the battery for 30mins, then did a relearn on it. Took it for another spin & tried very hard to get it to stall, A/C on & off, Sports mode, full auto, PRND all left idling for extended periods, no stalls!


                  Thank you to those who responded, especially Roofchop!

                  Comment

                  • disco stu
                    Valued Member
                    • Dec 2018
                    • 3106
                    • Wollongong

                    #10
                    Great news hope it's sorted permanently

                    Comment

                    • El_Freddo
                      Valued Member
                      • Nov 2018
                      • 675
                      • Bridgewater, Vic

                      #11
                      Awesome news. Hopefully it IS the solution you needed.

                      I love an easy fix like this.

                      Now you can tell your wife to put the rifle away

                      Cheers

                      Bennie
                      2005 NP DiD auto. The family bus. Dual batteries, snorkel, one side step, King Springs lift, Koni shocks, rear airman airbags, Provent catch can, 81L LRA tank (awesome!). Other rides: "Ruby Scoo" my lifted L series Subaru and my "Redback" Targa top Brumby - only mods are 5 poster bullbar and nicer dashboard from a coupe

                      Comment

                      • Roofchop
                        Member
                        • Jul 2018
                        • 175
                        • Carool, Australia

                        #12
                        Excellent news!


                        I got my car cheap as it had all the usual niggles of a 20 year old Pajero.


                        The young couple I got it from had been told it needed a new engine and as no mechanics could get the 4x4 working, a new gearbox as well!


                        Once sorted you end up with a very good 4x4 for a fraction the cost of a Toysan or Nisota


                        Cheers
                        Dave
                        2007 NS 3.8 V6 GLX Auto

                        Comment

                        • Having Fun
                          Senior Member
                          • Jun 2015
                          • 373
                          • Adelaide

                          #13
                          (apologies for the long-winded, probably boring post, but here's our story)

                          Yes, when they're working, they are pretty good. This one was very clean when we bought it. No dramas with it for the 1st two years we owned it. My wife wasn't keen on getting it stone chipped & full of red dust when she first got it, so we took our other car when we went Roper Bar/Lorella Springs/Hells Gate etc that year.

                          But it soon towed a caravan up to Rawnsley Park & drove around the gorges up in the Flinders, then on a bigger trip it went up the middle. We took it out through the east & west Mac's, including out to N'dala, Arltunga & even towed the caravan into/out of Redbank gorge (I'd never contemplate doing that again with any car lol) - on that trip we went up as far as Camooweal before torrential rain turned us around. We stopped in at Andamooka on the way back to Adelaide. The car performed faultlessly.

                          The next 12 months, it did mostly city driving, as we took our other car when we went on holiday, but the Pajero did get to do the Morgan/Yunta mail run, once again no dramas with the car.

                          The following year we had towed a camper up through the Hamilton Gate from Wanaaring, Thargo, Toompine, Quilpie & Windorah, Haddon Corner, no dramas, then the fun started! Every time we stopped the car the temp gauge would show hot within 300M of taking off again. Idle it on the roadside for a few minutes & down it would come. Drive all day without stopping & it was all good, but as soon as we stopped, then took off again up went the temp gauge! It was a tad stressful considering where we were lol. We were lucky enough to have 2 mechanics staying in the Birdsville caravan park go right over it for us pro bono, including full a full OBD check & they were left scratching their heads! Anyway, as it was not showing any obvious signs of overheating, other than the gauge, we took a gamble & continued on like that all the way home via Boulia/Jervois/Alice/Woomera.

                          Once home, it never happened again for over a year! (I can't work that out!) Radiator/water pump/thermostat all checked, nothing unusual found. When it did re-occur, it ended up being a failed gauge temp sensor.

                          In that year between the probs with the temp gauge, we 1st got the dreaded "chirp" & subsequent lack of interest in many workshops to even look at it. We finally found a guy to fit it for us.


                          A couple of moths later, we were on our way with it, towing a camper, the plan being Craddock/Marree/Oodnadatta/Mt. Dare/Old Andado/Santa Teresa/Alice/Kingoonya/Home. We got just past Burra & the dreaded flashing centre diff light started! Turned around, went home, changed cars, had a great trip, fixed the solenoids later!

                          Took it up the river for NYE & on the way home, right on a blind crest on a bend with double white lines, it went into limp mode for about 10M, then died completely, in the most dangerous place it possibly could have chosen! It eventually re-started & OBD tells me it was the camshaft angle sensor!

                          That was only 7 weeks ago & then we had the stalling drama last week. I'm fast coming to the conclusion that it's too old for the type of travel we do.

                          Comment

                          • Having Fun
                            Senior Member
                            • Jun 2015
                            • 373
                            • Adelaide

                            #14
                            Now it's got both O2 sensors on bank 2 showing error codes! Yea, I love this car lol

                            Comment

                            • deltaHU
                              Junior Member
                              • Mar 2024
                              • 4
                              • Hungary

                              #15
                              Originally posted by Having Fun View Post
                              Well changing the ECU coolant temp sensor seems to have done the job (I have literally everything crossed lol)
                              i have similar problem on a 2001 3.5 pajero.
                              i ordered the coolant sensor and hope it arrives this week.
                              will report if this was the solution.

                              Comment

                              Matched content

                              Collapse
                              Working...
                              X