Announcement

Collapse
No announcement yet.

Stutter under load at low RPM

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

    Stutter under load at low RPM

    Hi Guys,

    I've had my F02 730li for a while now and am really enjoying being back in a 7er. It's been generally running as it should and in good condition for a used car. Usual used car stuff - little dings on the body work, tyres were rubbish so replaced, DVD changer is knackered but not a problem, rear driver side blind is stuck in the down position. A few little niggles I plan to sort out as I go along and part of my enjoyment of being an engineer and owning a used car.

    I noticed this weekend a slight stutter or kinda misfire type of thing when gently accelerating from low rpm. I can almost recreate the symptom if I intentionally accelerate very gently from a slow speed and high gear. I always waft about in Comfort mode and the car never really gets much chance to hit high rpm never mind red line. I notice if I drive in sport mode the problem appears to go away, but the gear changes are a bit jerky. Is this likely an engine or transmission problem. I know the transmission is supposed to be life time requiring no maintenance, but I really don't like that idea. Car has now done 150k KM and I was going to pop it in for a service after a trip home to UK which is coming up shortly.

    The problem feels like its either spark plug or transmission related almost like low fluid (only from experience with problems with past owned cars) depending on which mode comfort or sport I drive in - strange!?.

    #2
    Hi

    I had a similar issue in my E60 5er. It turned out to be a transmission issue @ about 160K. I also had this issue where if you accelerate too quick the gear change would fail and would show up as "Transmission Fail" Error Alert. It would go away once i would turn off the engine and turn it back on.

    I could recommend you a garage if needed. For my car, they rebuilt the transmission with a rebuild kit. It has done 20K since and it runs like a smooth criminal :)

    I believe this issue comes up in the long run if you take off as soon as you turn on the engine and not let it run for a few seconds.

    Comment


      #3
      its could be an O2 sensor... you will need to have the codes to verify

      Comment


        #4
        Hi Guys,

        Thanks for the reply. Yes please let me have the details for the garage. I'll have them check both suggestions.

        No transmission or other faults/codes as yet (hope that doesn't jinx it!)... but that could be a matter of time.

        Comment


          #5
          Your issue seams to be spark plug related,but like the above post mentioned have the car scanned and do a smooth running test this will determine if the plugs are at fault !

          Comment


            #6
            Seen similar issues related to fuel, i had 4 catalytic converters blocked in my land cruiser due to fuel contamination, mainly from adnoc fuels no official confirmation but you can clearly see power / fuel economy difference when you fill up between special 95 and super 98. I'm lucky on the lc all it needed was injectors to be cleaned and i removed the cats and had spark plugs inspected. A family member had to get a brand new engine on their 650 gran coupe, and I've seen how many engine replacements were done under warranty at bmw, if the injectors are cleaned they isually recommend to update the dme to low quality fuel settings to avoid engine knocking, if there are score marks in the cylinders might be a big problem

            Comment


              #7
              Originally posted by ///DN View Post
              Seen similar issues related to fuel, i had 4 catalytic converters blocked in my land cruiser due to fuel contamination, mainly from adnoc fuels no official confirmation but you can clearly see power / fuel economy difference when you fill up between special 95 and super 98. I'm lucky on the lc all it needed was injectors to be cleaned and i removed the cats and had spark plugs inspected. A family member had to get a brand new engine on their 650 gran coupe, and I've seen how many engine replacements were done under warranty at bmw, if the injectors are cleaned they isually recommend to update the dme to low quality fuel settings to avoid engine knocking, if there are score marks in the cylinders might be a big problem
              Wow! so is it just the adnoc fuel or is it applicable to all fuel vendors (eppco, emarat etc...)

              Also were you filling 95 or 98? I always fill 98 thinking thats the best for the engine :S
              Current
              E92 M3 - Mineral White
              F80 M3 - SilverStone

              Past
              E36 318is
              E39 540i ///M sport
              VW CC
              E46 M3 - Frozen White

              Comment


                #8
                I can confirm for adnoc the issue has been ongoing almost almost a year now but differs from batch to batch, other vendors I'm not sure but less likely. The issues are only with the 95. Since adnoc don't have 98 across all stations in shj I've been mixing between 95 and 98. I always make a habit of filling up at one specific station to avoid problems with quality. Symptoms would be rough idle, engine knocking/vibration under acceleration, worse fuel economy and lower performance. Checklist would be the spark plugs injectors and cats.

                Comment


                  #9
                  Thanks ///DN...this is useful info....some of us can take some preventive measures this way. I'm still wondering why car manufacturers havent done anything about it. This should have a major impact on people staying in AUH.
                  Current
                  E92 M3 - Mineral White
                  F80 M3 - SilverStone

                  Past
                  E36 318is
                  E39 540i ///M sport
                  VW CC
                  E46 M3 - Frozen White

                  Comment


                    #10
                    I thought the same but issue is car manufacturers don't look at what quality fuel is at the pumps only what the fuel suppliers give as samples and analysis. One of the reasons diesel cars aren't supplied here, but they've stated they will be bringing in euro spec diesel to the market

                    Comment


                      #11
                      Any idea how much rebuilding a transmission would cost? I might be having similar issues with mine

                      Comment


                        #12
                        Garage

                        Originally posted by Monte View Post
                        Any idea how much rebuilding a transmission would cost? I might be having similar issues with mine
                        I usually get my car fixed at Ayham's garage - Das Autoworks. They've fixed the airbag warning light, suspension, etc in the past.

                        My E60 520i transmission was rebuilt at about AED 8K.

                        Comment

                        Working...
                        X