yng_750 247 Report post Posted May 6, 2012 i have a 1998 e39 m62b44 non vanos 540i did a good thousand kms of driving over the past weekend and after sitting for a day it seems to have developed a rough idle and has a small miss while driving. exhaust doesnt smoke or smell of fuel so possibly a mixture issue rather than complete miss things checked so far in order of what i thought prudent 1. put injector cleaner in, no immediate difference 2. pulled engine covers, no oil in galleries and no arcs off coil packs at night. one coil pack is marked 2007 and is a different brand to the others, looks like its been quite hot but no smells. 3. cleaned AFM and ICV. no immediate change but havent run on a cold morning yet, as that is when its at its worst. Will update Things to test. 4. Pull plugs (new plugs 9 months ago a per Service history) and check for discoloration that would indicate a bad coil or cracks in plug etc 5. investigate CCV valve. still not exactly sure where this is. back of the intake?? any guidance appreciated. 6. Get codes read, still trying to find a place in taupo for this, tossing up buying the cable from the UK. 7. Check for vacuum leaks or split hoses. going to attempt either gas or smoke test in a diy fashion. any other ideas or guidence on up and coming test appreciated will keep this updated and add pictures for others reference Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 8, 2012 pulled plugs all look ok cylinders 7 & 8 had a little oil on the plugs so i cleaned that up still running the same Just bought a code scanner tool so should know more by the end of the week Quote Share this post Link to post Share on other sites
mossline 15 Report post Posted May 8, 2012 Ive just had this same problem. Turned out to be a coil pack. Didnt throw any error codes so had me stumped for a while. Hope this helps pulled plugs all look ok cylinders 7 & 8 had a little oil on the plugs so i cleaned that up still running the same Just bought a code scanner tool so should know more by the end of the week Quote Share this post Link to post Share on other sites
BM WORLD 1258 Report post Posted May 8, 2012 unplug one coil at a time while running to see if it makes it idle worse, if not that could be the faulty coil Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 8, 2012 a member in taupo has offered the use of his scan tool i will use that first if i cant see anything i will unplug the coils one at a time and see what happens im guessing if i unplug them first then i will have an error code for each coilpack waiting for me anyway its pissing down today and we all know coil packs and rain dont mix Quote Share this post Link to post Share on other sites
elmarco 56 Report post Posted May 9, 2012 anyway its pissing down today and we all know coil packs and rain dont mix Haha - where's your sense of adventure??? Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 9, 2012 (edited) judging by how it doesnt seem overly rough but just has a rough idle when dead cold and seems abit flat i was already thinking it could have one bank running a poor mixture Turbolizard ran the codes for me this evening main responses were primary oxygen sensor for both banks and misfire on cylinders 4, 6 and 8 the misfire codes are likely from me playing with the coil packs and cleaning the plugs which caused it to miss for a few mins the cats do seem to get very hot very very quickly so quite possibly either blocked cats or my long drive has over heated them to the point of damaging the O2 sensors we cleared the codes and nothing reappeared after 5 mins of idling so i will wait a week and re check it and see what happens Edited May 9, 2012 by jason H Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2012 got the fuel tank down under 30km range then put half a tank of Z 95 octane in it seems to be a marked improvement maybe the bp 98 from hamilton was abit sh*t still not prefect so i might catch up with mike later this week and re run thecodes also i have bought a code reader but it has the OBD2 style plug anyone know if i can get an adaptor to the round 20 pin in nz? everything i can see online is EX uk Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 15, 2012 car seemed to be running very much better though not perfect until tonight drove home form work ok moved car out of driveway and parked on road ok went to drive to the pub and it has a masive misfire judging by the absolute lack of power and on off pulsing in the exhaust it seems like a whole bank is misfiring Coil packs etc and bone dry if it is the rains fault could is possibly be water on exposed o2 sensor wiring? could a dead o2 sensor completely kill a bank? Might see if mike can run my codes agin infuriating weather to try and fix a car in Quote Share this post Link to post Share on other sites
BM WORLD 1258 Report post Posted May 15, 2012 car seemed to be running very much better though not perfect until tonight drove home form work ok moved car out of driveway and parked on road ok went to drive to the pub and it has a masive misfire judging by the absolute lack of power and on off pulsing in the exhaust it seems like a whole bank is misfiring Coil packs etc and bone dry if it is the rains fault could is possibly be water on exposed o2 sensor wiring? could a dead o2 sensor completely kill a bank? Might see if mike can run my codes agin infuriating weather to try and fix a car in sounds more like faulty coils ,pretty common to go as they have a limited life , you might have a few that are failing Quote Share this post Link to post Share on other sites
zenetti 0 Report post Posted May 15, 2012 car seemed to be running very much better though not perfect until tonight drove home form work ok moved car out of driveway and parked on road ok went to drive to the pub and it has a masive misfire judging by the absolute lack of power and on off pulsing in the exhaust it seems like a whole bank is misfiring Coil packs etc and bone dry if it is the rains fault could is possibly be water on exposed o2 sensor wiring? could a dead o2 sensor completely kill a bank? Might see if mike can run my codes agin infuriating weather to try and fix a car in I have a very similar issue with the 735 E38 here. It is idling very rough when cold. Our scanner shows the 02 sensor as being the main culprit. We have switched them from side to side and are going to see what happens. I will scan it again in the morning and see what shows. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted May 16, 2012 95% of the time O2 sensor fault codes are the result of another problem....not the sensor Quote Share this post Link to post Share on other sites
Allanw 1051 Report post Posted May 16, 2012 95% of the time O2 sensor fault codes are the result of another problem....not the sensor Like if a coil isn't firing and the rich mixture/unburnt fuel upsets the O2 sensor and puts it "out of range". Lots and Lots of codes aren't the item the code is for... pain in the buttocks! Quote Share this post Link to post Share on other sites
Jono51 57 Report post Posted May 16, 2012 95% of the time O2 sensor fault codes are the result of another problem....not the sensor +1 Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 16, 2012 dickhead of the day award goes to me who forgot to reinstall the coil pack covers and has water down the spark plug tubes on cyl 7 and 8 Good C... of the day award goes to mike aka turbolizard who re ran my codes and didnt laugh at me for such a amateur mistake on the upside the only codes stored after a week of driving were for misfires on cyl 7 & 8 while wet so looks like everything else is running relatively well Still thinking cats are bad might plug a pressure gauge in and test the back pressure before the cats Quote Share this post Link to post Share on other sites
turbolizard 38 Report post Posted May 16, 2012 dickhead of the day award goes to me who forgot to reinstall the coil pack covers and has water down the spark plug tubes on cyl 7 and 8 Good C... of the day award goes to mike aka turbolizard who re ran my codes and didnt laugh at me for such a amateur mistake on the upside the only codes stored after a week of driving were for misfires on cyl 7 & 8 while wet so looks like everything else is running relatively well Still thinking cats are bad might plug a pressure gauge in and test the back pressure before the cats I have received good help from others on this board for nothing but a word of thanks. Glad I could do my bit to help someone else in return... Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 16, 2012 dont spose a really generous word of thanks would earn me the chance to drive an m5??? on second thought the fear of dinging something that impressive would have me glued to 50 so maybe not haha Quote Share this post Link to post Share on other sites
zenetti 0 Report post Posted May 17, 2012 95% of the time O2 sensor fault codes are the result of another problem....not the sensor sorry, I should have said more, we had misfiring on one bank of cylinders as well. We replaced all the spark plugs, took out the 02 sensors, gave them a clean and it seems to have solved the issuer. The car is running and driving a lot smoother! Quote Share this post Link to post Share on other sites
jochen 4 Report post Posted May 17, 2012 i have a 1998 e39 m62b44 non vanos 540i did a good thousand kms of driving over the past weekend and after sitting for a day it seems to have developed a rough idle and has a small miss while driving. exhaust doesnt smoke or smell of fuel so possibly a mixture issue rather than complete miss Use the BMW diagnostic software and do a smooth-running test You'll see what cylinder is the culprit The swap coils from suspect cylinder with a known good cylinder My money is a faulty coil, the above test will easily confirm it Quote Share this post Link to post Share on other sites
