power loss 330ci

[bmwins]

problem was Cam position sensor. were all good now.

[sonny]

Had the same issue with my 325 01. It was sluggish, slow, even the ac just wasn't pumping steady air.. got a new battery and it's good as new. Night and day difference..

[mamadci]

wow i've read about this problem (sluggish performance) in so many forums and i didn't find a solid solution to this. some people fixed it by replacing the CAM position sensor but most of them got the problem back after couple of weeks. some changed the spark plugs, battery (in the case of above, which is really weird), dirty throttle or MAF, and ...

now in my case, i scanned my car last week and i got two errors
1) something related to throttle controller being dirty or something
2) cylinder 4-6 mixing something
i knew i had a bad valve cover gasket since it was leaking so i changed it this past weekend, it was an easy job and kinda fun . next day CEL went off and car was much better. yesterday going back home from work it came back on and the performance was horrible, it was like a 316. now today coming to work it's much better. i'm really pissed, why this car behaves likes this arghhhhhhhhhhh. some days its just running awesome (25% of the time) and other times its just close to normal or bad performance. i'll keep you guys posted if i got this problem out of the way once in for all.

[The-Traveler]

A car should be able to run (after it has been started) with the battery disconnected, if it doesn't then you have a problem with the charging system... which usually implies the alternator is bad.

Replacing the battery should not improve any vehicle function while the car is on, if the alternator is operating correctly.

mamadci, perhaps you should remove the throttle body and ICV and clean them. It takes a couple of hours and to get to them you need to remove the intake box and the two bellows tubes then it's right there.

Clean them with brake cleaner then lube them up with SeaFoam DeepCreep (aerosol can available at PartSource and NAPA.) The lube is necessary.

[mamadci]

yeah thats my plan for this weekend to remove the ICV and throttle body and clean them up. i found a video on youtube showing how to do it so i'll give it try this weekend. there are some useful diy clips on youtube like the valve cover gasket DIY that i found extremely useful when i changed mine. god bless youtube and people who actually post these clips

Originally Posted by The-Traveler

A car should be able to run (after it has been started) with the battery disconnected, if it doesn't then you have a problem with the charging system... which usually implies the alternator is bad.

Replacing the battery should not improve any vehicle function while the car is on, if the alternator is operating correctly.

mamadci, perhaps you should remove the throttle body and ICV and clean them. It takes a couple of hours and to get to them you need to remove the intake box and the two bellows tubes then it's right there.

Clean them with brake cleaner then lube them up with SeaFoam DeepCreep (aerosol can available at PartSource and NAPA.) The lube is necessary.

[mamadci]

time for an update, so finally i changed my valve cover gaskets and my car is back man . huge difference from before no sluggishness anymore. i regret that i didn't do this earlier when i knew about it a year ago . Guys, this is an easy DIY, i did it in less than 3 hours. thank god i didn't do vanos seals cause i dont think it was necessary at this point.

so after all this i got an ECIS intake and man i love it. sound is amazing and i'm pretty sure my car is more responsive now specially in first and second gear. overall pretty happy with it so far.

so next, i'm planning to clean up my idle control valve and do an oil change. i'll keep you guys posted once i do these.

[Ahctuning]

Originally Posted by mamadci

time for an update, so finally i changed my valve cover gaskets and my car is back man . huge difference from before no sluggishness anymore. i regret that i didn't do this earlier when i knew about it a year ago . Guys, this is an easy DIY, i did it in less than 3 hours. thank god i didn't do vanos seals cause i dont think it was necessary at this point.

so after all this i got an ECIS intake and man i love it. sound is amazing and i'm pretty sure my car is more responsive now specially in first and second gear. overall pretty happy with it so far.

so next, i'm planning to clean up my idle control valve and do an oil change. i'll keep you guys posted once i do these.

Your car's computer is probably going thru an adaptation period or some other reason for the power loss. A VCG replacement is irrelevant to power loss.