Engine oscillations

supermann125 · 09-01-2016, 09:57 PM

I drive for a few miles a day in a speed limit of 25mph. I often just set the cruise to 26, equating to about 1400-1450 rpm. I've noticed when I do this, the engine will start bogging or oscillating between 1350 and 1500. Has anyone else experiences this?

BB_cuda · 09-01-2016, 11:54 PM

In School zones, I set cruise to about 21. It holds steady for me w/o oscillations.

EDITs:
Clarifying after reading Castle's response below. The speed setting stayed locked on at 21 and the engine RPM also didn't vary.

9/2/16: I went through same school zone and repeated cruise setting at 22 mph and rpm stayed steady at 1200 RPM. Not trying to speed (22 vs posted limit of 20) but lowest setting is either 20 or >20 mph. Most people still pass me. My other vehicle (Dodge, not BMW) can't set cruise below 35 mph.

Thecastle · 09-02-2016, 07:26 AM

Nope, no ossocilations here holds speed steady.

Hoooper · 09-02-2016, 10:05 AM

Can you get a video?

eric-satx · 09-02-2016, 04:41 PM

FWIW - I had the bouncing rpms at idle and low engine load. My car is still under CPO so I took it in. They replaced the fprv and no problem since,

supermann125 · 09-02-2016, 07:11 PM

Can't get a video (tried today), but may just bring it in and have them take a look (CPO). Maybe they can clean some CBU while they're at it

09-01-2016, 09:57 PM	#1
supermann125 Private First Class 45 Rep 182 Posts Drives: 2011 335d Join Date: May 2014 Location: Seattle, WA iTrader: (2)	Engine oscillations I drive for a few miles a day in a speed limit of 25mph. I often just set the cruise to 26, equating to about 1400-1450 rpm. I've noticed when I do this, the engine will start bogging or oscillating between 1350 and 1500. Has anyone else experiences this?
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09-01-2016, 11:54 PM	#2
BB_cuda Brigadier General 776 Rep 3,559 Posts Drives: 2011 335D Msport, 2013 X5D Join Date: Nov 2011 Location: Clear Lake, Texas iTrader: (0)	In School zones, I set cruise to about 21. It holds steady for me w/o oscillations. EDITs: Clarifying after reading Castle's response below. The speed setting stayed locked on at 21 and the engine RPM also didn't vary. 9/2/16: I went through same school zone and repeated cruise setting at 22 mph and rpm stayed steady at 1200 RPM. Not trying to speed (22 vs posted limit of 20) but lowest setting is either 20 or >20 mph. Most people still pass me. My other vehicle (Dodge, not BMW) can't set cruise below 35 mph. Last edited by BB_cuda; 09-02-2016 at 11:42 AM..
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09-02-2016, 07:26 AM	#3
Thecastle Major 325 Rep 1,167 Posts Drives: F10 550i Join Date: Apr 2015 Location: Houston, TX iTrader: (0) Garage List 2020 BMW M340i [0.00] 2019 RAM 3500 [0.00] 2020 BMW X3 [0.00] 2016 BMW 550i [0.00] 2000 Ford F450 7.3l ... [0.00]	Nope, no ossocilations here holds speed steady.
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09-02-2016, 10:05 AM	#4
Hoooper Colonel 213 Rep 2,210 Posts Drives: 335D Join Date: Jun 2013 Location: Petaluma, CA iTrader: (0)	Can you get a video?
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09-02-2016, 04:41 PM	#5
eric-satx New Member 3 Rep 19 Posts Drives: 2011 335d Join Date: Aug 2015 Location: satx iTrader: (0)	FWIW - I had the bouncing rpms at idle and low engine load. My car is still under CPO so I took it in. They replaced the fprv and no problem since,
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09-02-2016, 07:11 PM	#6
supermann125 Private First Class 45 Rep 182 Posts Drives: 2011 335d Join Date: May 2014 Location: Seattle, WA iTrader: (2)	Can't get a video (tried today), but may just bring it in and have them take a look (CPO). Maybe they can clean some CBU while they're at it
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