symptom : at idle the engine misses a beat approx every 15-20 seconds.the sound can be heard from the exhaust note and noticeable with the tachometer dropping about 100rpm but recovering straight away to steady idle at 750rpm.if gear in D,the car will jerk everytime this happens and very annoying at traffic lights and traffic jams.when cruising no jerk. solution : i am lucky to have friends who change stuff due to "trial and error" recommendation from their mechanics .in this case i was given(for free) 6 'suspect' ignition coils,which i know for sure is good.so i replaced the coils starting from the #1 position - no change.2nd coil - voila.....smooth idle. cost - 1 hour and 0 rm so bad ignition coils can cause lumpy idle...also bad cam pos sensor,bad crank pos sensor,bad plugs,bad etc etc.....you know the drill
m52b28 lumpy idle
- Thread starter moots
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Dear all,
Need some views on this. My yr 2000 528i had been on the original coils up to 2 yrs back when one of the coils gave way. I changed one and its back to normal. Up to last yr, another coil gave way...changed another one and the remaining 4 original bosch still holding on. But eventually changed all 4 not long after that.
Now, i occassionally get the misfire especially when long idle at traffic queue. Also, the misfire can easily be triggered if switch off the air-con. Turn off engine and restart, things get back to normal. What do you guys think the problem is? Pening gak ni...
Need some views on this. My yr 2000 528i had been on the original coils up to 2 yrs back when one of the coils gave way. I changed one and its back to normal. Up to last yr, another coil gave way...changed another one and the remaining 4 original bosch still holding on. But eventually changed all 4 not long after that.
Now, i occassionally get the misfire especially when long idle at traffic queue. Also, the misfire can easily be triggered if switch off the air-con. Turn off engine and restart, things get back to normal. What do you guys think the problem is? Pening gak ni...
bmw7833;594644 said:
he he.....kalau dua dua merajuk....ana kawin tiga.....
normally the others merajuk coz u replace new.mine all used part of the same manufacture year.kalau merajuk replace one by one lor....got another 5 on standby
moots;594797 said:
moots,
Called my mechanic on the CPS. I told him that my idle is now a bit rough, there a slight hesitation in acceleration and there was an incident that the engine suddenly died off during a slow crawl. He said it is possible the fault is on the CPS but said dont discount the camshaft sensors as well. I'm gonna get both checked. How much are the CPS and the camshaft sensors? Mine a double vanos, so i think there are two camshaft sensors. TQ
Misifiring on Cyl 4
Swapped all 6 injectors with used ones...still..the misfire on cyl 4 came only after 2 minutes. Next to check is the voltage at the injectors. If that turns out ok...then have to do the compression test. Wish me luck...
JFT63;600750 said:
Swapped all 6 injectors with used ones...still..the misfire on cyl 4 came only after 2 minutes. Next to check is the voltage at the injectors. If that turns out ok...then have to do the compression test. Wish me luck...
Finally, did compression test on the cylinders. Eureka!! pressure was at 8 level in cyl 4 whereas the rest of the 5 cylinders are pumping 11 to 12. So, top overhaul began and stranded my UDM for about 5 days. What happened was one of the exhaust valves on cyl 4 had a cracked on the trumpet part. You can actually see thru the valve...heh heh. There was also a "crack menanti belah" on cyl 5 as well. So, changed the valves to new ones and did the grinding on all of the valves. Of course replaced some of the typical gaskets on the way. Now no more misfire, idle is creamy smooth and engine gives more punch. Mileage was 240,000 km. Havent got the bill yet. But can expect about RM3k plus...hisk hisk
bimmerholic
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Did you also skim your cylinder head? What i understand from skimming cylinder head during top overhaul is that, it'll increases your compression ratio.
bimmerholic;638804 said:
Didn't do any skimming. My mech said not to mess with the standard compression unless your head needs it due to misfortune such as overheating etc. Even if skimming is needed, he'd retain the compression via thicker gaskets.
