Hesitation between 1100 and 1900 RPM

F

fernando306

Member
Guys,

This been a battle since day one.
- New MAF Siemes VDO from FCP Euro https://www.fcpeuro.com/products/bmw-mass-air-flow-sensor-13627566983
- New Vanos seals
- Refurbished DISA
- New spark plugs
- Injectors cleaned
- Fuel pump pressure test good
etc.

Car has 90k miles now, runs GREAT, super strong and idles smoothly and quiet. However, in normal daily driving when you turn a corner in 3rd gear and the RPM drops below 2k, foot on the gas, and the car hesitates some. Once it approaches 2k RPM, all is good again, loads of torque.

I disconnected the MAF, problem is gone. No more low RPM hesitation.
What then!? Thoughts?
 
Hi, it is possible that there is a problem with the new MAF/ the one that you replaced. Not unheard of to get faulty new parts.. Has the hesitation been there since you replacrd the MAF?
 
When a new maf is installed you should reset the adaptations, basically re-learn with the new maf. Were there any codes/live data before fitting the new one?
 
Hey guys, definitively I cleared all adaptations for the new MAF.

In regards to old vs new MAF, when I got the car it had a Chinese MAF and it was total crap. Acceleration was lumpy and unpredictable. The new MAF improved everything above 2k, but like I mentioned, when I disconnect the MAF, the acceleration is nice and even across all range. It is possible that the new MAF is busted, I think I'll get it exchanged with FCP Euro.

Any other thoughts of possible causes?
 
Hi, I was having exactly the same problem with my si coupe. It was like I’d apply the usual throttle and it would take a moment to do anything and it would be very random.

I’d also had some chirruping from the serpentine auxiliary belt and under inspection the oil cooler was seeping and dripping oil over the belt.

I had a new belt put on and oil cooler seals done and a few other pipes which oil had dripped on and the problem has completely disappeared.

The thinking goes that if the alternator properly and cause electrical problems that manifest in different ways. I did a bit of research as I’m not mechanically minded and there is some evidence to support this.
So maybe worth having someone check the condition of the belt and tensioners.
 
Since the problem went away when you disconnected the MAF it is most likely that your new MAF is bad.
 
Gosh, that is just frustrating, isn't it? I paid $200 for this Siemens VDO MAF, I may return it and pay the difference for a Genuine BMW. Now, if that doesn't fix it... Then URRRGHHH :headbang:
 
Oem were either Siemens or Bosch, surprised the Siemens is duff out of the box, cheap Chinese versions are a waste of time they seldom last long or work correctly if at all. Been down that road with mine, replacement with a oem Bosch one fixed my problems straight away. Buy cheap and you end up paying twice as they say, same for all the other sensors on these cars, I have had good results using Hass camshaft sensors on a couple of cars so would reccommend that Brand.
 
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