M3 E36 3.0, occasional rough idle...
Discussion
hello, car is m3 e36 3.0, 1994 year, 115000 miles, oil level ok, mobil 1 5w50, before one week we test vanos and all is ok with no engine codes, compression is ok, vanos test ok, emission test ok, new spark plugs, engine start ok...
I drive to home from my friend. 100km easy driving and on freeway I wanted to little blow engine in 4th gear 3500-5000 rpm for maybe 10 minutes and 3 minutes 2-3 gear 5000-6000rpm in the city. When I park car engine shakes like have destroyed internals, idle is around 550-600rpm, but car go ok. Just before I start to drive car from my friend we little rev engine in idle and everything is just normal. No lights on cluster. When I start engine again (engine start normal), oil pressure lamp turn off for 1 sec, idle is ok for 2 sec and again go into crazy work. When I disconnect maf on live, engine sound change so I think that maf work. We reset dme and engine work like new for 10-30 minutes and again low and rough idle.
before two days we reset dme for third time and engine work like new for two days...Today, after 60miles trip on highway again low/shaking idle and sometimes little shaking under throttle to 1500rpm. We reset dme and engine again work ok. My mechanic suspect vanos, that maybe is stuck...This time in dme is stored eror like cluster dont get speed signal (geschwidinkait...) but cluster work ok...
why engine run properly for some time when we reset dme I dont know...
today I change oil from m1 5w50 to fuchs titan race pro s 10w50...
video with engine running:
http://www.youtube.com/watch?v=JaoyHegx8TA
I drive to home from my friend. 100km easy driving and on freeway I wanted to little blow engine in 4th gear 3500-5000 rpm for maybe 10 minutes and 3 minutes 2-3 gear 5000-6000rpm in the city. When I park car engine shakes like have destroyed internals, idle is around 550-600rpm, but car go ok. Just before I start to drive car from my friend we little rev engine in idle and everything is just normal. No lights on cluster. When I start engine again (engine start normal), oil pressure lamp turn off for 1 sec, idle is ok for 2 sec and again go into crazy work. When I disconnect maf on live, engine sound change so I think that maf work. We reset dme and engine work like new for 10-30 minutes and again low and rough idle.
before two days we reset dme for third time and engine work like new for two days...Today, after 60miles trip on highway again low/shaking idle and sometimes little shaking under throttle to 1500rpm. We reset dme and engine again work ok. My mechanic suspect vanos, that maybe is stuck...This time in dme is stored eror like cluster dont get speed signal (geschwidinkait...) but cluster work ok...
why engine run properly for some time when we reset dme I dont know...
today I change oil from m1 5w50 to fuchs titan race pro s 10w50...
video with engine running:
http://www.youtube.com/watch?v=JaoyHegx8TA
ICV (idle control valve) is mechanical part which work or dont work. How reseting dme can "repair" icv for some time (10-20min)??? When we reset dme engine work ok for short time. Same thing is with hoses. Maybe reseting dme use some default parameter for short time (and work ok) and then try to learn new parameters. If something mechanical is broken, like icv or vacuum hoses then dme can learn wrong parameters. Teach me, I try to think logical.
Pull the air filter box and elbow off, check all the small bore air hoses under the plenum for tiny splits first. Also check the larger two up around the throttle bodies. They may look ok but perish with age and will disintegrate if you push on them.
This is a common m3 fault and those symptoms sound dead on.
carreauchompeur said:
I've had the same problems with my car I am taking it apart next week have seen your thread on M3 cutters and will update..
great!!! I hope that you will find solution...The biggest mystery is that the engine runs properly after resetting ECU. What happens later, I do not know.
foler said:
carreauchompeur said:
I've had the same problems with my car I am taking it apart next week have seen your thread on M3 cutters and will update..
great!!! I hope that you will find solution...The biggest mystery is that the engine runs properly after resetting ECU. What happens later, I do not know.
I change my oil from mobil 1 5w50 (2 year old, maybe 8k miles on them) to fuchs titan race pro s 10w50 and so far so good for several days. Engine run quiter and smoother. I will know more when I return from 600 miles trip for several days. Maybe is oil m1 5w50 after some time to thin for build oil pressure and vanos cant work properly. maybe!!!
foler said:
I change my oil from mobil 1 5w50 (2 year old, maybe 8k miles on them) to fuchs titan race pro s 10w50 and so far so good for several days. Engine run quiter and smoother. I will know more when I return from 600 miles trip for several days. Maybe is oil m1 5w50 after some time to thin for build oil pressure and vanos cant work properly. maybe!!!
Is the recommended oil for these cars not Castrol TWS (10W60)?VinceFox said:
Pull the air filter box and elbow off, check all the small bore air hoses under the plenum for tiny splits first. Also check the larger two up around the throttle bodies. They may look ok but perish with age and will disintegrate if you push on them.
This is a common m3 fault and those symptoms sound dead on.
+1This is a common m3 fault and those symptoms sound dead on.
Had similar with my Evo, a few hoses under the plenum can't be seen so worth taking off to check. The crankcase breather system hoses disintegrate over time from the fumes and they sit right under the plenum (think 3.0 the same although different system to the 3.2?)
Make sure you take off and check the bellows from the MAF to the plenum too, mine failed day before the MOT.
It can idle pretty well even with some leaks and sometimes only effect the idle when warm (holes open up under temperature) but once all mine was sorted it had the best emission figures it's ever had for years!
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