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      10-19-2021, 11:52 PM   #1
Ashhong
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Hi all, I've posted in a few threads trying to find some answers but I'm at my wits end and need some help. Below are the steps of what has happened so far

1. Replaced valve cover gasket
2. Replaced oil filter housing gasket
3. Slightly cracked the head of the charge pipe while doing 2, ignored it
4. Tested the car by idling only. Engine shakes a little when first booting it, and then over time the RPMs just keep dropping. At around 500-550, engine misfires and revs up the RPMs to about 1k, and then everything repeats.
5. Found codes P112F and P0171
6. Bought and installed a VRSF charge pipe thinking that could be the problem.
7. Same shaking issue, same codes
8. Did a smoke test and could not find a leak (what point is the best to test the smoke from?)

I think that's everything. Does anybody have any idea what it could be? The car drives fine for the most part, but just can't idle. I've found the descriptions for those codes but I just can't pinpoint what the issue is. Please help!

Correction: the car does not drive that great. When I come to a stop at all abruptly, the RPMs dip to around 500, car shakes, and revs up to 1k
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      10-20-2021, 05:22 AM   #2
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Following. Have experienced a similar issue intermittently.

Wonder if your throttle body has some buildup, might be a good idea to check and make sure the plate is able to open and close freely.
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      10-20-2021, 08:46 AM   #3
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Did this happen right after your valve cover gasket replacement? Theres no leak through the chargepipe crack?
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      10-20-2021, 11:18 AM   #4
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Quote:
Originally Posted by Ashhong View Post
Hi all, I've posted in a few threads trying to find some answers but I'm at my wits end and need some help. Below are the steps of what has happened so far

1. Replaced valve cover gasket
2. Replaced oil filter housing gasket
3. Slightly cracked the head of the charge pipe while doing 2, ignored it
4. Tested the car by idling only. Engine shakes a little when first booting it, and then over time the RPMs just keep dropping. At around 500-550, engine misfires and revs up the RPMs to about 1k, and then everything repeats.
5. Found codes P112F and P0171
6. Bought and installed a VRSF charge pipe thinking that could be the problem.
7. Same shaking issue, same codes
8. Did a smoke test and could not find a leak (what point is the best to test the smoke from?)

I think that's everything. Does anybody have any idea what it could be? The car drives fine for the most part, but just can't idle. I've found the descriptions for those codes but I just can't pinpoint what the issue is. Please help!

Correction: the car does not drive that great. When I come to a stop at all abruptly, the RPMs dip to around 500, car shakes, and revs up to 1k
P0171 is usually the result of a vacuum leak. After a 2 min search, since I've never seen P112F, that too is a caused by a vacuum leak. I bolded #1, reason being is if you didn't have this issue before and now you do, something may have happened when performing step #1.

Two places I would investigate.
  • First one is where the yellow arrow is pointing at. Check that connection and the other end where it connects to. (IF YOU HAVE EWG IT WILL NOT BE PRESENT, ONLY PRESENT ON PWG)
  • Check the hose to the right of the arrow which is directly behind the oil fill cap. That crankcase breather hose connects to the inlet of the turbo. This could be broken or damaged, or may not even be fully seated.

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      10-20-2021, 11:50 AM   #5
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Quote:
Originally Posted by 5w20 View Post
P0171 is usually the result of a vacuum leak. After a 2 min search, since I've never seen P112F, that too is a caused by a vacuum leak. I bolded #1, reason being is if you didn't have this issue before and now you do, something may have happened when performing step #1.

Two places I would investigate.
  • First one is where the yellow arrow is pointing at. Check that connection and the other end where it connects to. (IF YOU HAVE EWG IT WILL NOT BE PRESENT, ONLY PRESENT ON PWG)
  • Check the hose to the right of the arrow which is directly behind the oil fill cap. That crankcase breather hose connects to the inlet of the turbo. This could be broken or damaged, or may not even be fully seated.

+1, saw the same thing when i googles those codes. The VC can create a vacuum leak, even if the CP doesn't. If you didnt replace the CCV hose during VCG and it is original it is likely very brittle, i replaced mine when i did an inlet and at only 45k miles it was falling apart.

Also, when you did the smoke test, did you pressurize?

Did you try unplugging the MAF? I thought i just linked the other thread with that procedure recently but let me know if you can't find it.
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      10-20-2021, 11:53 AM   #6
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Found the thread with the MAF discussion: https://f30.bimmerpost.com/forums/sh...8#post28101828
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      10-20-2021, 12:30 PM   #7
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Quote:
Originally Posted by BMWILUVU View Post
Did this happen right after your valve cover gasket replacement? Theres no leak through the chargepipe crack?
Well directly after the vcg I did the ofhg. Not sure if it had this issue in between. The CP has already been replaced but I am going to double check my install today

Quote:
Originally Posted by 5w20 View Post

P0171 is usually the result of a vacuum leak. After a 2 min search, since I've never seen P112F, that too is a caused by a vacuum leak. I bolded #1, reason being is if you didn't have this issue before and now you do, something may have happened when performing step #1.

Two places I would investigate.
  • First one is where the yellow arrow is pointing at. Check that connection and the other end where it connects to. (IF YOU HAVE EWG IT WILL NOT BE PRESENT, ONLY PRESENT ON PWG)
  • Check the hose to the right of the arrow which is directly behind the oil fill cap. That crankcase breather hose connects to the inlet of the turbo. This could be broken or damaged, or may not even be fully seated.

[IMG]https://www.2addicts.com/forums/atta...8;d=1461193176[/IMG]
Funny you mention that, we saw that hole during the install and were freaking out why there's no hose. I still need to verify that I have an EWG but there's def no hose so im sure I do. Will check that other hose today

Quote:
Originally Posted by thejeremyman9 View Post
+1, saw the same thing when i googles those codes. The VC can create a vacuum leak, even if the CP doesn't. If you didnt replace the CCV hose during VCG and it is original it is likely very brittle, i replaced mine when i did an inlet and at only 45k miles it was falling apart.

Also, when you did the smoke test, did you pressurize?

Did you try unplugging the MAF? I thought i just linked the other thread with that procedure recently but let me know if you can't find it.
Is the CCV hose that second hose mentioned above? No we didn't pressurize, just put smoke in. And the MAF is the one on the intake right? We cleaned it but didn't try turning on the car with it unplugged. I'll try that as well
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      10-20-2021, 12:34 PM   #8
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Quote:
Originally Posted by Ashhong View Post
Well directly after the vcg I did the ofhg. Not sure if it had this issue in between. The CP has already been replaced but I am going to double check my install today


Funny you mention that, we saw that hole during the install and were freaking out why there's no hose. I still need to verify that I have an EWG but there's def no hose so im sure I do. Will check that other hose today


Is the CCV hose that second hose mentioned above? No we didn't pressurize, just put smoke in. And the MAF is the one on the intake right? We cleaned it but didn't try turning on the car with it unplugged. I'll try that as well
Yeah CCV hose is the one with the insulation over it, goes from VC to turbo inlet, and clips on the VC with the 4 prongs. You can't really see the hose itself because of the insulation, and it can become brittle and crack where you can't see it.

MAF is on the intake yes, right after the airbox.

OFHG shouldn't have the potential for a vacuum leak, but VC does.
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      10-20-2021, 01:30 PM   #9
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Quote:
Originally Posted by thejeremyman9 View Post
Quote:
Originally Posted by Ashhong View Post
Well directly after the vcg I did the ofhg. Not sure if it had this issue in between. The CP has already been replaced but I am going to double check my install today


Funny you mention that, we saw that hole during the install and were freaking out why there's no hose. I still need to verify that I have an EWG but there's def no hose so im sure I do. Will check that other hose today


Is the CCV hose that second hose mentioned above? No we didn't pressurize, just put smoke in. And the MAF is the one on the intake right? We cleaned it but didn't try turning on the car with it unplugged. I'll try that as well
Yeah CCV hose is the one with the insulation over it, goes from VC to turbo inlet, and clips on the VC with the 4 prongs. You can't really see the hose itself because of the insulation, and it can become brittle and crack where you can't see it.

MAF is on the intake yes, right after the airbox.

OFHG shouldn't have the potential for a vacuum leak, but VC does.
How does one check the CCV hose through the insulation? Is there a spot where it breaks most often?

I was thinking maybe the OFHG because I had to take the intake off a bit and shift it over. It's how I cracked my CP in the first place.

Also would you mind explaining how the VC could produce a vacuum leak? My understanding is it's just oil
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      10-20-2021, 01:42 PM   #10
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Quote:
Originally Posted by Ashhong View Post
How does one check the CCV hose through the insulation? Is there a spot where it breaks most often?

I was thinking maybe the OFHG because I had to take the intake off a bit and shift it over. It's how I cracked my CP in the first place.

Also would you mind explaining how the VC could produce a vacuum leak? My understanding is it's just oil
Not sure how you can check it without removing it or somehow sliding off the insulation. I had one on hand when i swapped my inlet and i heard mine cracking the moment i tried to remove it, so i just installed the new one. It can crack anywhere along its length really.

FCP discusses how the VC is used: https://blog.fcpeuro.com/bmw-n55-x5-...ymptoms-review
"Since the valve cover also acts as the vacuum reservoir, any cracks here will create vacuum leaks. This will lead to rough running and wastegate issues. "

If you removed intake manifold, you could have also created a vacuum leak there.

A smoke test should be enough to reveal a vacuum leak, but you need to make sure the smoke is getting past the TB. Pressurizing with the smoke also helps.
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      10-20-2021, 02:11 PM   #11
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Quote:
Originally Posted by thejeremyman9 View Post
Quote:
Originally Posted by Ashhong View Post
How does one check the CCV hose through the insulation? Is there a spot where it breaks most often?

I was thinking maybe the OFHG because I had to take the intake off a bit and shift it over. It's how I cracked my CP in the first place.

Also would you mind explaining how the VC could produce a vacuum leak? My understanding is it's just oil
Not sure how you can check it without removing it or somehow sliding off the insulation. I had one on hand when i swapped my inlet and i heard mine cracking the moment i tried to remove it, so i just installed the new one. It can crack anywhere along its length really.

FCP discusses how the VC is used: https://blog.fcpeuro.com/bmw-n55-x5-...ymptoms-review
"Since the valve cover also acts as the vacuum reservoir, any cracks here will create vacuum leaks. This will lead to rough running and wastegate issues. "

If you removed intake manifold, you could have also created a vacuum leak there.

A smoke test should be enough to reveal a vacuum leak, but you need to make sure the smoke is getting past the TB. Pressurizing with the smoke also helps.
Thanks for the info, I'll check out that vc thread butttt

I removed the MAF now, but not at a cold start, and the issue was gone! Plugged it back in and it came back immediately.

So now from what I saw in the other thread, people remove the MAF on a cold start, let it run, turn it off, then plug it back in? Just ordered a new air filter and will do the MAF stuff after it comes in.

How can I reset the adaptations for the MAF? I only found instructions for the transmission
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      10-20-2021, 02:24 PM   #12
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Quote:
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Thanks for the info, I'll check out that vc thread butttt

I removed the MAF now, but not at a cold start, and the issue was gone! Plugged it back in and it came back immediately.

So now from what I saw in the other thread, people remove the MAF on a cold start, let it run, turn it off, then plug it back in? Just ordered a new air filter and will do the MAF stuff after it comes in.

How can I reset the adaptations for the MAF? I only found instructions for the transmission
Well unplugging the MAF could have just covered up a vacuum leak since the issue with a vacuum leak is that it is letting in unmetered air lol.

You can reset adaptations with MHD/BM3, but if you don't have either of those, not sure if there are any free apps that can do so.
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      10-20-2021, 02:29 PM   #13
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Quote:
Originally Posted by thejeremyman9 View Post
Quote:
Originally Posted by Ashhong View Post
How does one check the CCV hose through the insulation? Is there a spot where it breaks most often?

I was thinking maybe the OFHG because I had to take the intake off a bit and shift it over. It's how I cracked my CP in the first place.

Also would you mind explaining how the VC could produce a vacuum leak? My understanding is it's just oil
Not sure how you can check it without removing it or somehow sliding off the insulation. I had one on hand when i swapped my inlet and i heard mine cracking the moment i tried to remove it, so i just installed the new one. It can crack anywhere along its length really.

FCP discusses how the VC is used: https://blog.fcpeuro.com/bmw-n55-x5-...ymptoms-review
"Since the valve cover also acts as the vacuum reservoir, any cracks here will create vacuum leaks. This will lead to rough running and wastegate issues. "

If you removed intake manifold, you could have also created a vacuum leak there.

A smoke test should be enough to reveal a vacuum leak, but you need to make sure the smoke is getting past the TB. Pressurizing with the smoke also helps.
This video talks about the vacuum reservoir on the N55 valvecover.



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      10-20-2021, 02:29 PM   #14
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Quote:
Originally Posted by thejeremyman9 View Post
Quote:
Originally Posted by Ashhong View Post
Thanks for the info, I'll check out that vc thread butttt

I removed the MAF now, but not at a cold start, and the issue was gone! Plugged it back in and it came back immediately.

So now from what I saw in the other thread, people remove the MAF on a cold start, let it run, turn it off, then plug it back in? Just ordered a new air filter and will do the MAF stuff after it comes in.

How can I reset the adaptations for the MAF? I only found instructions for the transmission
Well unplugging the MAF could have just covered up a vacuum leak since the issue with a vacuum leak is that it is letting in unmetered air lol.

You can reset adaptations with MHD/BM3, but if you don't have either of those, not sure if there are any free apps that can do so.
Ah that makes sense. I got a little excited. I checked the things mentioned above and everything seemed ok, tho I didn't get a good look at the CCV. Gonna wait and replace the filter and all that and we'll see…
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      10-22-2021, 09:10 PM   #15
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Quote:
Originally Posted by 5w20 View Post
This video talks about the vacuum reservoir on the N55 valvecover.



So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. Does that mean the reservoir is not there for EWG cars or is it just somewhere else?
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      10-23-2021, 09:04 AM   #16
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Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by 5w20 View Post
This video talks about the vacuum reservoir on the N55 valvecover.



So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. Does that mean the reservoir is not there for EWG cars or is it just somewhere else?
The "reservoir" on top of the VC is actually the PCV valve. All N55's have them.

The CCV hose gets brittle over time so it's best to just replace it rather than diagnosis it for leaks.
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      10-23-2021, 02:53 PM   #17
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Quote:
Originally Posted by F32Fleet View Post
Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by 5w20 View Post
This video talks about the vacuum reservoir on the N55 valvecover.



So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. Does that mean the reservoir is not there for EWG cars or is it just somewhere else?
The "reservoir" on top of the VC is actually the PCV valve. All N55's have them.

The CCV hose gets brittle over time so it's best to just replace it rather than diagnosis it for leaks.
I'm looking into replacing it now. Do you happen to know the screw type it uses on these cars? I read it's hard to get to so I want to be ready
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      10-23-2021, 04:18 PM   #18
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Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by F32Fleet View Post
Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by 5w20 View Post
This video talks about the vacuum reservoir on the N55 valvecover.



So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. Does that mean the reservoir is not there for EWG cars or is it just somewhere else?
The "reservoir" on top of the VC is actually the PCV valve. All N55's have them.

The CCV hose gets brittle over time so it's best to just replace it rather than diagnosis it for leaks.
I'm looking into replacing it now. Do you happen to know the screw type it uses on these cars? I read it's hard to get to so I want to be ready
It should come with the screw
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      10-24-2021, 06:03 PM   #19
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Quote:
Originally Posted by F32Fleet View Post
Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by F32Fleet View Post
Quote:
Originally Posted by Ashhong View Post
Quote:
Originally Posted by 5w20 View Post
This video talks about the vacuum reservoir on the N55 valvecover.



So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. Does that mean the reservoir is not there for EWG cars or is it just somewhere else?
The "reservoir" on top of the VC is actually the PCV valve. All N55's have them.

The CCV hose gets brittle over time so it's best to just replace it rather than diagnosis it for leaks.
I'm looking into replacing it now. Do you happen to know the screw type it uses on these cars? I read it's hard to get to so I want to be ready
It should come with the screw
Ya talking about the existing one though. Still wanted to check before I buy.
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      10-24-2021, 06:12 PM   #20
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Quote:
Originally Posted by Ashhong View Post
So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. -- correct no hose

Does that mean the reservoir is not there for EWG cars or is it just somewhere else? -- vacuum reservoir is probably still there but it sealed off somewhere inside of that hole, otherwise we would all have vacuum leaks.
see answers in red
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      10-24-2021, 11:22 PM   #21
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Quote:
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Quote:
Originally Posted by Ashhong View Post
So unless I'm mistaken, that vacuum hose is not there if you have an EWG as posted above. [COLOR="Red"]-- correct no hose[/COLOR]

Does that mean the reservoir is not there for EWG cars or is it just somewhere else? [COLOR="red"]-- vacuum reservoir is probably still there but it sealed off somewhere inside of that hole, otherwise we would all have vacuum leaks. [/COLOR]
see answers in red
Is there a video with checking that vacuum on cars without that hose?
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      10-24-2021, 11:25 PM   #22
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Quote:
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Is there a video with checking that vacuum on cars without that hose?
No, its sealed off. You would hear a vacuum leak or possibly see oil down in the hole if you have a problem there on a EWG equipped vehicle.
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