Hesitation during acceleration

[cparker]

I just discovered today that during acceleration (through all gears) I am getting some intermittent hesitation in the 2000-3000rpm neighborhood. Kinda like the car jerks as it speeds up.

I just bought the car and I have not done a "tune up" yet, I have new spark plugs and filters already on order. Is there anything I should be worried about? The car has 92k miles.

[RITmusic2k]

If it's specifically from 2800-3000 it's very likely a software issue. Several forum members have corrected this problem by getting DME updates. I suffer from this as well, though I haven't yet had the chance to rectify it. Maybe this weekend while we're at the Crevier museum I can have them take a look for me.


The other possibility is that it's a VANOS issue. I'd try to get a software update first, since that'd be the cheaper solution and if it takes care of the problem, you'll never have to worry about it again.

[danewilson77]

Do you have a SES light?

Your issue could be vanos. With that mileage, I would say it's suspect. My car has 125k, and I have a bit o the jerk......i am sure due to vanos. No codes.

www.beisansystems.com

[cparker]

SES? Is that the check engine light? I have no fault lights on. I had a pre-purchase inspection done and codes were checked, I was told it had not fault codes although I'm kinda pissed that they did not discover this issue during the pre purchase inspection... but then again it took me a few days to notice it.

Do I have to get a DME (?) update through the dealer or how does that work?

[danewilson77]

You have a DME...or ECU. That's the cars computer

I would hinge bets that your vanos needs rebuilt.

[cparker]

Gotcha. The acronym threw me off. The vanos repair looks pretty straight forward. I don't really know if mine rattles, but if I've already got it apart I may as well install the rattle kit.

I will order the materials to rebuild it so they're on the way. I'm going to be replacing the spark plugs tonight and the fuel filter as soon as it arrives. I'd rather take one step at a time so I know for sure what fixed it. Hopefully the vanos kit will be here for next weekend.

[kpro]

Vanos for sure, my car is reallly really bad about the hesitation. It just keeps getting worse. Im pretty sure a geo metro can take my car in a race at this point. Mine is the worst with a/c on and between 2500-3000 RPMs.

[cparker]

That's good to know because I was a little dissapointed by the car's power output so hopefully rebuilding the vanos will help.

[mimalmo]

Rev that bish to 4k RPM, dump the clutch, upshift at redline, rinse, repeat. Follow those instructions and you'll never find yourself below 3k RPM.

[VA//M3]

That's good to know because I was a little dissapointed by the car's power output so hopefully rebuilding the vanos will help.

It will.

It made a massive difference on my car and a new DISA valve really brought the engine back up to life.

Also,



Taking the vanos solenoids out allows you to clean all the passages in the vanos body. Also BMW sells a vanos piston and seal kit pictured below. for about 40 dollars.

One person reported that the new vanos piston spring was longer then the older one that came out. so replacing the vanos pistons is a good idea.



http://www.realoem.com/bmw/showparts...70&hg=11&fg=15

Part number 3 and 4.

2 x 11361703713
2 x 11367560298

Also these parts can break upon removal and it is good to order them

Parts 9, 10, and 17 two of each and the sealing gasket partnumber 19