E46 330ci anyone found a fix for power drop when warmed up ?

[Gammelhagger01]

After surfing the net for a few months, trying to find a fix for the problem I have, it seems to me that a lot of E46 owners have experienced some of the same issues regarding periodic power loss/ dragging feeling when the engine is warmed up.
I was wondering if anybody found a fix ???

I know it can relate to many sources...... fueling or ignition... but I would love to learn if anyone has had the problem and found a fix..... regardles of which fix....

I have done all the usual E46 stuf... From vanos to vacum hoses, DISA, MAF, CCV, TPS ect. Only have I not yet changed the coils, fuel pump or filter.....

NO Fault codes are thrown !!!

[bmwmike]

Can't really help other than I always found my m52tub25 engine slightly more spritely when cold and assumed it was the extra fuel being dumped in during warm up. Didn't occur to me it might be a fault.

If on the other hand you're cruising along and the car starts to slow/drag I'd be looking at brakes etc.

[anonymous-user]

Gammelhagger01 said:

After surfing the net for a few months, trying to find a fix for the problem I have, it seems to me that a lot of E46 owners have experienced some of the same issues regarding periodic power loss/ dragging feeling when the engine is warmed up.
I was wondering if anybody found a fix ???

I know it can relate to many sources...... fueling or ignition... but I would love to learn if anyone has had the problem and found a fix..... regardles of which fix....

I have done all the usual E46 stuf... From vanos to vacum hoses, DISA, MAF, CCV, TPS ect. Only have I not yet changed the coils, fuel pump or filter.....

NO Fault codes are thrown !!!

I'm afraid I can't help you specifically but this is something we've seen with the wife's SLK350 on occasion. Cruising along at, say, 70 when you get this feeling that the brakes are being applied, something's dragging, just as you describe.

The other thing we see, which might be worth you checking, is that the recent average fuel consumption starts to fall dramatically. Have you noticed that? When our car last did it we had done 6 miles at an average of 32mpg. Over the next 3 miles that fell to 25mpg which indicates that for some reason, without warning and at a steady, flat road cruise, the fuel consumption had dropped into the 11/12mpg range. The remaining range falls accordingly. Then it just stopped as quickly as it had started.

When the car's done this in the past I've taken it into the dealer, who just looks at me askance. There are no fault codes so they don't seem to have any idea what is causing it.

This last time, however, wife was with me and she filmed the dash whilst the fuel consumption reading was in free fall, and the video shows the cruising speed and distance covered so the dealer couldn't fob me off. They've admitted they don't know what it is but have "reprogrammed the gearbox and fuel pump" whatever that means.

Anyway, point is, if your issue is similar, it does appear to be a random over fuelling issue, IMO. Our car has done it 3 times in the last 3000 miles or so, 18 month old car, with 9000 miles.

I appreciate these are different cars but perhaps there's something there to help?

[diehardbenzfan]

Have you tried the camshaft sensor or the crankshaft sensor? I had a 330i auto and was lighting quick when cold, but when warmed up, the car would feel like its a 1.8 until 4000 rpm, after 4k the full 230 horses are active lol, a mechanic told me it could be either of those 2 sensors so I bought them and before they arrived, some idiot wrote it off, wasnt able to find out what it was but I bought another one and it was not only quicker, but a lot smoother and more ecnomical! Might be the sensors mate

[Maxus]

diehardbenzfan said:

Have you tried the camshaft sensor or the crankshaft sensor? I had a 330i auto and was lighting quick when cold, but when warmed up, the car would feel like its a 1.8 until 4000 rpm, after 4k the full 230 horses are active lol, a mechanic told me it could be either of those 2 sensors so I bought them and before they arrived, some idiot wrote it off, wasnt able to find out what it was but I bought another one and it was not only quicker, but a lot smoother and more ecnomical! Might be the sensors mate

That to me sounds like Vanos seals. Mine lost some of its "spark" when warm. Below 3,000 rpm it felt like you had to put effort in to get it going. Not 1.8 slow though!
I changed the vanos seals a few weeks ago and the difference is noticeable. Below 3,000 revs you can now feel that something is helping to push it along (variable timing).
Of course, poor performance could be caused by many things.

[gibson2004]

I had this problem on my 2003 e46 330ci, also had the same problem with the z3 3.0, Problem was the cam position sensor. Most of the time it wont flag up as a fault as its not completely failing.

A way to make sure it is the sensor failing is to plug the car into a software like IMPA which display real time information about the car.

I also cant stress enough, always buy OEM! Ive bought after market sensors only for them to not work at all.