M62 Engine surge
 

Trying to track down the cause of my partial throttle engine surge. Would love some help/ideas on what it could be. It happens with partial throttle application. Imagine an onramp to highway and you feed in the throttle and it accelerates but it fluctuates/hesitates until you reach speed. Very frustrating. I have done the following:
*smoked the EVAP system-all tight
*sprayed ether/carb cleaner all around intake/vacuum hose areas
*did a vacuum test at idle-15-20in vacuum
*have checked all hoses/intake plenum connections
*disconnected the MAF/no change
This just happened a couple of weeks ago after reassembly(again) of my VANOS repairs. No codes are being thrown either. Doesn't seem to be affected by engine temp. Blast away.
Thanks

You could try cleaning the MAF but since it is directly associated with the vanos project, I suggest you go back over your work. Did you rebuild the vanos?

Reset adaptations via coding.

Bcredliner
 

Thanks for the help. I will try cleaning the MAF. I won't bore you with the details, but I have had the top end of this motor apart many times recently trying to diagnose a knock/tick noise. I did rebuild the VANOS and suspected it was tied to that work. I have looked everywhere and do not see any faults. I reset adaptations yesterday and it seems to help sporadically. But the issue comes up intermittently again.

Am I correct assuming you used the lockdown kit needed to keep the engine in time when you removed the Vanos? Is the knock/tick noise still present?

tools
 

Bcred, Yes I do have the correct tools to do the timing. Thank God, since I have had to use them numerous times….Yes the noise is still present. I have even swapped out the VANOS unit for a known good one on bank 2 where the noise is. I had my stethoscope under the car with it jacked up yesterday and the most noise at this point is coming from the exhaust manifold. I am going to take the LF wheel and the fender liner out and put the probe on each individual exhaust header coming out of the head. It was also suggested to me to systematically remove the wiring from one cylinder at a time and see if the noise abates. This will supposedly tell me whether it is a rod/wrist pin/piston issue or not. Anxious to try it.