E92 M3 Vacuum Pump won't stop.....

tizzyd · 05-25-2021, 09:03 PM

Hi all,

So happy to be back where it all started, in an E92. I recently had the opportunity to purchase a 9k mile 2013 E92 M3 Comp (DCT) and jumped at it. Only issue was, the car had been in storage and mice had some fun under the hood, and the car kept going into limp mode, the only fault being for insufficient vacuum. First thing we found was a nest around the brake booster, and they had chewed some of the vacuum lines there, which were replaced. We also had to replace the vacuum pump as it wasn't creating enough vacuum to pass the test through ISTA, car kept going into limp mode. Once everything on the brake side was finished, it still kept running and limp mode ensued. We smoke tested it, ran the vacuum test again and all was fine, but limp mode kept coming back.

Well, we then took off the plenum and BAM another huge nest in the V of the engine. Took all that out, everything appeared to be ok but the vacuum pump continued to run incessantly and the car kept going into limp mode. What we found was that on the intake side, the check valve had sucked in some nesting material that was interfering. We replaced the hose that had the check valve in it, and while limp mode has not come back after around 100 miles, the vacuum pump still runs every 10 seconds or so, only while ON LIGHT THROTTLE. So, off throttle or on the brakes/holding the brakes, no pump. On light throttle application, it keeps running. We are at a loss here.....see the video for an example. Is this normal?

Helmsman · 05-26-2021, 01:52 AM

And guess you've replaced the vacuum sensor as well?

Redd · 05-26-2021, 04:18 AM

Yeah brake vacuum sensor. It's like 20 bucks or so.

cognoscenti · 05-26-2021, 08:20 AM

Agree on the vacuum sensor. I had similar behavior when I had the brakes bled during regular maintenance, and the shop wasn't careful enough with the brake fluid reservoir during the procedure. It leaked fluid onto the sensor and caused the issue. They replaced it (at their cost) and the problem was fixed.

nycplumber · 03-22-2022, 04:13 PM

Did you ever resolve this?

Scrippy · 03-22-2022, 06:42 PM

Quote:

Originally Posted by Redd

Yeah brake vacuum sensor. It's like 20 bucks or so.

I bought just the sensor and it was still $110. Where can I find it for $20? I'd like to keep one in the garage.

k_mann · 03-22-2022, 08:49 PM

I made a thread on this. You can buy an OEM diff pressure sensor (it's the same thing but a different part number because it's not the whole hose assembly)

27E4 Brake Vacuum Sensor GOOD NEWS https://www.m3post.com/forums/showthread.php?t=1714625

nycplumber · 03-22-2022, 10:03 PM

Thanks I ordered the sensor a few days ago but also had some other symptoms as well. Hopefully the sensor fixes it

Properstyle · 06-15-2022, 09:40 AM

Quote:

Originally Posted by k_mann

I made a thread on this. You can buy an OEM diff pressure sensor (it's the same thing but a different part number because it's not the whole hose assembly)

27E4 Brake Vacuum Sensor GOOD NEWS https://www.m3post.com/forums/showthread.php?t=1714625

did you have to replace the fuse as well. IF so what number was it. I've yet to find the correct FUSEBOX lay out for a 2011 E90m3 very. I have a late build 2011.75

Jastreb · 06-15-2022, 01:51 PM

When I replaced my bad sensor, I did not need to replace any fuses.

k_mann · 06-17-2022, 08:47 PM

Quote:

Originally Posted by Properstyle

Quote:

Originally Posted by k_mann

I made a thread on this. You can buy an OEM diff pressure sensor (it's the same thing but a different part number because it's not the whole hose assembly)

27E4 Brake Vacuum Sensor GOOD NEWS https://www.m3post.com/forums/showthread.php?t=1714625

did you have to replace the fuse as well. IF so what number was it. I've yet to find the correct FUSEBOX lay out for a 2011 E90m3 very. I have a late build 2011.75

No I did not have to do anything with any fuses

05-25-2021, 09:03 PM	#1
tizzyd Captain 238 Rep 610 Posts Drives: 2011 335i 6MT Join Date: Feb 2008 Location: USA iTrader: (0) Garage List 2003.5 BMW M3 [0.00] 2011 335i Coupe [8.50]	E92 M3 Vacuum Pump won't stop..... Hi all, So happy to be back where it all started, in an E92. I recently had the opportunity to purchase a 9k mile 2013 E92 M3 Comp (DCT) and jumped at it. Only issue was, the car had been in storage and mice had some fun under the hood, and the car kept going into limp mode, the only fault being for insufficient vacuum. First thing we found was a nest around the brake booster, and they had chewed some of the vacuum lines there, which were replaced. We also had to replace the vacuum pump as it wasn't creating enough vacuum to pass the test through ISTA, car kept going into limp mode. Once everything on the brake side was finished, it still kept running and limp mode ensued. We smoke tested it, ran the vacuum test again and all was fine, but limp mode kept coming back. Well, we then took off the plenum and BAM another huge nest in the V of the engine. Took all that out, everything appeared to be ok but the vacuum pump continued to run incessantly and the car kept going into limp mode. What we found was that on the intake side, the check valve had sucked in some nesting material that was interfering. We replaced the hose that had the check valve in it, and while limp mode has not come back after around 100 miles, the vacuum pump still runs every 10 seconds or so, only while ON LIGHT THROTTLE. So, off throttle or on the brakes/holding the brakes, no pump. On light throttle application, it keeps running. We are at a loss here.....see the video for an example. Is this normal? __________________ 2007 E60 M5 6MT (Interlagos/Silverstone Full) \| 2013 F10 M5 6MT (Imola Red/Black Full) \| 2022 BMW M5 CS (Brands Hatch Grey) \| 2006 E46 M3 Comp 6MT (Silver Grey/Black, CSL clone) \| 2011.5 E92 M3 (Fire Orange/Black Recaros, 4.6L Stroker, GTS Clone) \| 2011 1M (Valencia Orange/Black)
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05-26-2021, 01:52 AM	#2
Helmsman Major General 4465 Rep 7,108 Posts Drives: 2011 AW E90 M3 ZCP Join Date: Mar 2014 Location: Stockholm, Sweden iTrader: (0)	And guess you've replaced the vacuum sensor as well?
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05-26-2021, 04:18 AM	#3
Redd Brigadier General 3897 Rep 4,160 Posts Drives: 2010 BMW E92 M3 Dakar Edition Join Date: Jul 2015 Location: Malaysia iTrader: (0)	Yeah brake vacuum sensor. It's like 20 bucks or so.
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05-26-2021, 08:20 AM	#4
cognoscenti Second Lieutenant 79 Rep 207 Posts Drives: 2011.75 E90 M3 6MT ZCP MR Join Date: Aug 2016 Location: North Carolina iTrader: (1)	Agree on the vacuum sensor. I had similar behavior when I had the brakes bled during regular maintenance, and the shop wasn't careful enough with the brake fluid reservoir during the procedure. It leaked fluid onto the sensor and caused the issue. They replaced it (at their cost) and the problem was fixed.
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03-22-2022, 04:13 PM	#5
nycplumber Major 682 Rep 1,227 Posts Drives: slow Join Date: Apr 2016 Location: nyc iTrader: (0)	Did you ever resolve this?
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03-22-2022, 08:49 PM	#7
k_mann Lieutenant 372 Rep 445 Posts Drives: 2018 M2 Join Date: Mar 2016 Location: Kansas City iTrader: (0) Garage List 2018 BMW M2 [10.00]	I made a thread on this. You can buy an OEM diff pressure sensor (it's the same thing but a different part number because it's not the whole hose assembly) 27E4 Brake Vacuum Sensor GOOD NEWS https://www.m3post.com/forums/showthread.php?t=1714625 __________________ Current: 2018 M2 DCT Previous: 2011 E92 M3, 2007 E92 328xi Insta: @kmannc
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03-22-2022, 10:03 PM	#8
nycplumber Major 682 Rep 1,227 Posts Drives: slow Join Date: Apr 2016 Location: nyc iTrader: (0)	Thanks I ordered the sensor a few days ago but also had some other symptoms as well. Hopefully the sensor fixes it
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06-15-2022, 01:51 PM	#10
Jastreb Downshifting 6 Rep 15 Posts Drives: 2010 E92 BMW M3, DCT Join Date: Apr 2021 Location: S.E. Michigan iTrader: (0)	When I replaced my bad sensor, I did not need to replace any fuses.
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