[Pavlo335]

Originally Posted by theOkilla

Hello, new to the forum but did not find a solution via the search function. I recently purchased a 2007 335i A/t with 85k miles on it. I purchased a package of parts from Arm Motorsports and installed them.

Initially I installed:
5" Stepped Intercooler, Charge pipe w/ Tial BOV, Dual-cone Intake and upgraded intercooler piping. I also installed new spark plugs and flashed the MHD Stage 1+ tune on it. The car was driving amazing and felt incredibly responsive and quick compared to stock. I noticed the low-end throttle response was a huge upgrade.

After a week, I decided to install my Arm Motorsports catless downpipes. It was a nightmare to install but eventually got them on. The o2 sensors did see some abuse unfortunately and the silicone housing got a little beat up. Additionally, the wires got twisted during install because I left them hooked up in the engine bay. (Mistake, I should have attached them to DPs before they were on the car)

I started up the car and didn't notice and bad signs or noises. I flashed the MHD Stage 2+ tune on the car and took it for a spin. I immediately noticed a sever lack of low end grunt, and the car feels like it's bogged down/hesitating between 1-2k RPMs with a very low amount of power and throttle response. Then it spools up and surges with power, but still doesn't feel right. When in 3rd or 4th gear WOT it gives me a 30FF engine code and goes into limp mode. Even before the code, the car feels significantly weaker than when it was in 1+ and working properly.

I took the downpipes off and re-installed them, doubling checking the bolts are not in the way of the wastegate actuator arm, I can take a picture tomorrow and post to verify they are correct. Still got the code, so I double checked all connections on the intake system, charge pipe, etc and found no leaks. I did a DIY smoke test and the only visible smoke to be released was out of the intakes where I had the PVC caps in to block them. I double checked the o2 sensors were in the correct positions, and never got an o2 code.

I noticed some vacuum lines were pretty frayed, and have new lines coming in the mail. However, I'm confused because all these issues happened immediately after the downpipes install.

Any and all help would be greatly appreciated. I just need suggestions on what the issue could be.

Thank you in advance.

Sorry to revive this thread but I am wondering if you ever found out the cause for the loss of power/bogging at lower rpms? I am experiencing a similar issue, my car had a slight hiccup at idle but otherwise ran great. No ses light and the car had great power but a slight hiccup at times when idling so I brought it to the shop (car is completely stock btw). My mechanic told me that my bk2 charge pipe was leaking and that the v-band clamp on my downpipe was installed incorrectly and causing a leak. He charged me $1600 for the fix and when I picked the car up, on my way home I immediately noticed a very significant loss of power and what sounds like an intake leak (loud whistle/whoosh of air at 2500+ rpms). I took the car back to my mechanic and he told me that he went over all of his work and that everything was installed correctly but that my intercooler had a minor leak that could be the issue. This sounds odd to me because the car had great power prior to the work being done and never made that noise. After worked I climbed underneath the car to have a look for myself and immediately I could hear a leak coming from my downpipe and when I put my hand near it I can feel a strong air leak coming from it. I am confident this is the noise I have been hearing but could a leak like that cause such a loss of power? I am curious if op ever got to the bottom of this issue and if it was related to the downpipe gaskets/v-band clamps

[Jerain]

Originally Posted by Pavlo335

Sorry to revive this thread but I am wondering if you ever found out the cause for the loss of power/bogging at lower rpms? I am experiencing a similar issue, my car had a slight hiccup at idle but otherwise ran great. No ses light and the car had great power but a slight hiccup at times when idling so I brought it to the shop (car is completely stock btw). My mechanic told me that my bk2 charge pipe was leaking and that the v-band clamp on my downpipe was installed incorrectly and causing a leak. He charged me $1600 for the fix and when I picked the car up, on my way home I immediately noticed a very significant loss of power and what sounds like an intake leak (loud whistle/whoosh of air at 2500+ rpms). I took the car back to my mechanic and he told me that he went over all of his work and that everything was installed correctly but that my intercooler had a minor leak that could be the issue. This sounds odd to me because the car had great power prior to the work being done and never made that noise. After worked I climbed underneath the car to have a look for myself and immediately I could hear a leak coming from my downpipe and when I put my hand near it I can feel a strong air leak coming from it. I am confident this is the noise I have been hearing but could a leak like that cause such a loss of power? I am curious if op ever got to the bottom of this issue and if it was related to the downpipe gaskets/v-band clamps

1600 bucks is ridiculous for such a small fix. Go back to him asap and let him fix it for free.

[Saif2018]

Originally Posted by Pavlo335

Sorry to revive this thread but I am wondering if you ever found out the cause for the loss of power/bogging at lower rpms? I am experiencing a similar issue, my car had a slight hiccup at idle but otherwise ran great. No ses light and the car had great power but a slight hiccup at times when idling so I brought it to the shop (car is completely stock btw). My mechanic told me that my bk2 charge pipe was leaking and that the v-band clamp on my downpipe was installed incorrectly and causing a leak. He charged me $1600 for the fix and when I picked the car up, on my way home I immediately noticed a very significant loss of power and what sounds like an intake leak (loud whistle/whoosh of air at 2500+ rpms). I took the car back to my mechanic and he told me that he went over all of his work and that everything was installed correctly but that my intercooler had a minor leak that could be the issue. This sounds odd to me because the car had great power prior to the work being done and never made that noise. After worked I climbed underneath the car to have a look for myself and immediately I could hear a leak coming from my downpipe and when I put my hand near it I can feel a strong air leak coming from it. I am confident this is the noise I have been hearing but could a leak like that cause such a loss of power? I am curious if op ever got to the bottom of this issue and if it was related to the downpipe gaskets/v-band clamps

$1600 for a v band /charge pipe fix?!!!

This mechanic you went to is a Thief, he ripped you off big time.

You probably have a boost leak, have you checked any codes with INPA /Protool or better yet done a log using MHD or JB4 etc?

[Pavlo335]

Originally Posted by Saif2018

$1600 for a v band /charge pipe fix?!!!

This mechanic you went to is a Thief, he ripped you off big time.

You probably have a boost leak, have you checked any codes with INPA /Protool or better yet done a log using MHD or JB4 etc?

Sorry for the delayed response. I was charged 10+ hours of labor for this job. When i got the car back I have 3 new codes i did not have prior to dropping it off and the car runs much more poorly. The new codes are: 30FF - boost leak, 2DC3 - Monitoring terminal 15, 2E8D - Intelligent battery sensor signal transmission and the original code that I had when I brought it to the shop which is 2C7E- Oxygen sensor control. The reason I brought my car to this shop was because they had the best reviews I could find for any bmw mechanic near me. I don’t have the means to jack my car up because I live in an apartment however I got underneath the car while it was idling and I could feel air leaking out from the downpipe gasket that he replaced. I did a data log using protool as my car is stock and I do not have jb4 or mhd. The lambda (afr) values shoot up from 14 all the way to 235+ when i give the car gas, meanwhile the target remains around 14. I don’t know much about afr but I’m guessing the exhaust leak at the downpipe is causing the o2 readings to get all screwed up. I would upload the data log here but to be honest I am not sure how. I called the mechanic again and he said to bring it in this Thursday but I am not sure if I even want to let this guy touch my car again.

[Emilime75]

I think there is some confusion here,. You said charge pipe, but I think you meant down pipe, bank 2 downpipe to be more specific.

Down pipe issues shouldn't cause 30ff, unless the v-band clamp was installed in a way that prohibits movement of the waste gate actuator arm, which is a possibility. An exhaust or down pipe leak could cause AFRs to be wonky, but so could a faulty O2 sensor. It's sounding like you may have multiple issues which may/may not be related. Neither of the above is likely to have anything to do with the IBS code.

To further add to the confusion, you first said you had no codes/SES, but then said you originally brought it in for an O2 code.

Either way, $1600 is way expensive for what they did, especially since they didn't fix the original complaint.

[Pavlo335]

Originally Posted by Emilime75

I think there is some confusion here,. You said charge pipe, but I think you meant down pipe, bank 2 downpipe to be more specific.

Down pipe issues shouldn't cause 30ff, unless the v-band clamp was installed in a way that prohibits movement of the waste gate actuator arm, which is a possibility. An exhaust or down pipe leak could cause AFRs to be wonky, but so could a faulty O2 sensor. It's sounding like you may have multiple issues which may/may not be related. Neither of the above is likely to have anything to do with the IBS code.

To further add to the confusion, you first said you had no codes/SES, but then said you originally brought it in for an O2 code.

Either way, $1600 is way expensive for what they did, especially since they didn't fix the original complaint.

I apologize for the confusion. When i originally brought the car in there was no SES/warning lights but I did have a code, 2C7E- oxygen sensor control which was not triggering the SES light. The mechanic told me the “back charge pipe” which goes around the motor had a hairline fracture and was causing an intake leak, and he also said the v-band clamps on the downpipe were installed incorrectly and causing an exhaust leak at the downpipe. He said he replaced both the charge pipe and the downpipe v-band clamps along with the gaskets. When I got the car back it is still not throwing an SES light but I now have the 3 new codes which I mentioned in my previous comment along with the original oxygen sensor code. The car also has a very noticeable loss of power since I got it back, it has almost no torque in higher gears and there is a loud air whooshing noise when going above 2500rpms, which i believe is the exhaust leak that I discovered at the downpipe gasket after it was supposedly fixed.

[Emilime75]

Thank you for the clarification, but this yields in even more discrepancies. Maybe it's just you misinterpreting what the mechanic said, or he's either completely incompetent or just simply lied to you.

Let's start with the "back charge pipe". There is no such thing on a 335i. There is a back(rear) down pipe, and a back(rear) inlet. The down pipes are on the passenger(right) side of the motor and connect to the exhaust. The rear inlet is between the back of the motor and the firewall. Neither of these would cause an intake leak.
Keep in mind you have 2 down pipes and 2 inlets. Both down pipes are next to each other, but one is called the front and the other rear because they serve their respective turbo, bank 1(front) and bank 2(rear). The other inlet is in front of the engine, between it and the radiator fan. This one feeds the bank 1(front) turbo, while the rear feeds bank 2(rear) turbo.

The part that actually is the charge pipe does not have v-band style clamps on it. It consists of two parts, the lower and upper charge pipe. It is located on the driver's (left) side of the motor. The lower connects to the intercooler with a spring clip and has an internal O-Ring as a seal(unless you have an aftermarket intercooler which uses worm/t-style clamps). From there it connects to the upper with a worm or t-style clamp. It finishes off at the throttle body with another spring clip and internal O-Ring. If any of these were leaking you could/will experience loss of power and a 30ff code.

The down pipe v-band clamps being installed incorrectly and causing an exhaust leak is plausible. This could, potentially be the cause of your O2 sensor code, but not extremely likely. You might just have an aged O2 sensor on its way out.

Maybe take a video, upload to YouTube and post a link here. Point out what he called the down pipe and charge pipe, get some footage of the woosh sound you're hearing and, if you can, show where you think the exhaust leak is.

It doesn't sound like you're very DIY, but of you could post a log it would be much more helpful in diagnosis.

[Pavlo335]

Originally Posted by Emilime75

Thank you for the clarification, but this yields in even more discrepancies. Maybe it's just you misinterpreting what the mechanic said, or he's either completely incompetent or just simply lied to you.

Let's start with the "back charge pipe". There is no such thing on a 335i. There is a back(rear) down pipe, and a back(rear) inlet. The down pipes are on the passenger(right) side of the motor and connect to the exhaust. The rear inlet is between the back of the motor and the firewall. Neither of these would cause an intake leak.
Keep in mind you have 2 down pipes and 2 inlets. Both down pipes are next to each other, but one is called the front and the other rear because they serve their respective turbo, bank 1(front) and bank 2(rear). The other inlet is in front of the engine, between it and the radiator fan. This one feeds the bank 1(front) turbo, while the rear feeds bank 2(rear) turbo.

The part that actually is the charge pipe does not have v-band style clamps on it. It consists of two parts, the lower and upper charge pipe. It is located on the driver's (left) side of the motor. The lower connects to the intercooler with a spring clip and has an internal O-Ring as a seal(unless you have an aftermarket intercooler which uses worm/t-style clamps). From there it connects to the upper with a worm or t-style clamp. It finishes off at the throttle body with another spring clip and internal O-Ring. If any of these were leaking you could/will experience loss of power and a 30ff code.

The down pipe v-band clamps being installed incorrectly and causing an exhaust leak is plausible. This could, potentially be the cause of your O2 sensor code, but not extremely likely. You might just have an aged O2 sensor on its way out.

Maybe take a video, upload to YouTube and post a link here. Point out what he called the down pipe and charge pipe, get some footage of the woosh sound you're hearing and, if you can, show where you think the exhaust leak is.

It doesn't sound like you're very DIY, but of you could post a log it would be much more helpful in diagnosis.

Thank you for all of the information and helping me understand everything. You’re correct I’m not very diy, I wish I could be but I just don’t have the necessary space or time. I do have a general understanding of the car but there is a lot I don’t know and I am new to datalogging and to be completely honest I don't know what most of the values mean. I just uploaded my first datalog here: https://datazap.me/u/pavlo335/datalog-1?log=0&data=1-24-25

This log was taken after I got my car back from the shop and when I took this log I did two small pulls and did not go WOT or high in the rpms because I am afraid to drive the car hard if something is wrong with it. I will try to get a better log tomorrow and a video of the noise I was describing. I don’t know if it’s helpful but I also have a log from a few days before I brought the car to the shop when the car was running much better and pulling with full power. I will upload that one tomorrow too.

I know that there are two downpipes, one corresponding with each turbo, and I know the downpipes are under the passenger side of the car. When I get under there and put my hand near the downpipes with the car idling, I am feeling hot air escaping from where I believe is the v-band clamps. I will also get a video or pictures of this tomorrow.

As far as the charge pipe, I was under the impression that all of the intake piping from the intercooler to the turbo could be considered a “charge pipe”. When my mechanic told me he was going to replace my charge pipe I told him that I was looking into getting an aftermarket intercooler and chargepipe anyway, so I may as well wait until then to replace it, he responded by saying that this is a different charge pipe and he was going to replace the “back charge pipe”. To be honest I should have asked him to keep the original parts so I could see exactly what he replaced and I feel like an idiot for not doing so. I guess you live and you learn

Thank you again for taking the time to educate me and provide guidance with my struggles. This community really is the best.

[Emilime75]

The piping between the turbos and intercooler intake is called outlets, as they take out coming air from the turbos to the intercooler. This is considered the hot side of the intake tract as the air coming from the turbos is hot. The piping coming from the intercooler output to the throttle body is the charge pipe. This is considered the cold side of the intake, as the air is compressed not only from the turbos, but the cooling of it also has a condensing effect and the combination is the air being "charged".

The only thing I could possibly think of that someone might call a rear charge pipe would be the rear inlet. This is the pipe that takes filtered air from your air filter to the rear turbo intake. This is never pressurized, it is under vacuum as the turbo spools and sucks in air. A leak in this pipe would not result in any drivability issues. The only down side would be that unfiltered air might be getting to the turbos and the engine. Replacing this actually is a lot of work and I can see why he might have charged as much as he did for the work, i.just question the validity of the diagnosis and the decision that this needed replacement.

[Pavlo335]

Originally Posted by Emilime75

The piping between the turbos and intercooler intake is called outlets, as they take out coming air from the turbos to the intercooler. This is considered the hot side of the intake tract as the air coming from the turbos is hot. The piping coming from the intercooler output to the throttle body is the charge pipe. This is considered the cold side of the intake, as the air is compressed not only from the turbos, but the cooling of it also has a condensing effect and the combination is the air being "charged".

The only thing I could possibly think of that someone might call a rear charge pipe would be the rear inlet. This is the pipe that takes filtered air from your air filter to the rear turbo intake. This is never pressurized, it is under vacuum as the turbo spools and sucks in air. A leak in this pipe would not result in any drivability issues. The only down side would be that unfiltered air might be getting to the turbos and the engine. Replacing this actually is a lot of work and I can see why he might have charged as much as he did for the work, i.just question the validity of the diagnosis and the decision that this needed replacement.

I don’t think I can express enough how much I appreciate you taking the time to explain everything in laymans terms to me so I can better understand what is going on with my car.

What you said was spot on. I took the car back to my mechanic this morning, showed him the exhaust leak that I was talking about, and asked him to show me the charge pipe that he replaced. He went into the shop and came out with a plastic pipe that looked nothing like the charge pipe. I asked him “is this the pipe that runs from the intercooler to the throttle body?” and he said “no, thats the charge pipe that runs from the air filter to the turbos”. I said “so this pipe is under vacuum, that wouldn’t cause an intake leak or performance issues” and he responded by saying “yes it would” I did not want to argue with him further but what you said makes total sense and I wish I would have never let him replace that inlet which he called the charge pipe.

Yesterday I tried to get a video of the whistle/whooshing noise I have been hearing ever since the car was worked on but I was having difficulty capturing the noise on camera due to the fact you have to have the windows open and be accelerating above 2500 rpm to hear the noise and the wind coming into the car makes it nearly impossible to capture. The mechanic also tried to tell me this noise is completely normal for a stock n54 but I know my car and I know for a fact this noise is not normal.

I did get a picture of where the exhaust leak that I have been talking about is coming from which I will include in this post. Correct me if I am wrong but I believe that this is right at the v-band clamps that he said he replaced. He also told me that the exhaust leak would not be causing any of my issues.

I told him about the new codes I am getting ever since getting the car back and how the air to fuel ratios seem very off. I left the car with him and asked him to go over the job that was done and check all of the gaskets and flanges. At the end of the day he sent me this video: https://youtu.be/0wApw5OKvVQ

I don’t know the anything about the values that he is showing me in the video but I don’t believe the injectors could a problem as I recently replaced all of them with a brand new set of index 12s. I am at a loss here and I don't know what to do

[Emilime75]

OK, so he's got his terminology wrong. What he replaced is what is known as an "inlet" and your N54 has 2 of them, one in the front to the front turbo and one in the rear of the motor to the rear turbo. I am just about positive that a leak anywhere in either inlet would not cause any issues aside from potentially allowing unfiltered air to get into your turbos and engine through the intake system...which is bad in the long run, but would not cause any drivability problems.

The exhaust leak is evident in the photo. You can see how the flange appears to have a gap at the gasket and the black soot from the exhaust gas leaking on the bottom. It looks like there are new nuts, but the studs on the downpipes look very rusty so they probably had trouble tightening things down. Curious if they now replaced the rusty studs with new bolts. FYI, those are not v band clamps. They are merely 2 flanges that are bolted together with a gasket in between them.

On to the video.

The additive mixture adaptations being "stuck" at 0 is a good thing. These are known as short term fuel trims, or STFT, and are the adaptations the DME is making with the engine at idle. Since he was showing those with the car idling in his shop, there is nothing wrong here.

The multiplicative mixture adaptations are a little suspect to me. These are known as long term fuel trims, or LTFT. I agree with him that they shouldn't differ the way they are and should be close to each other. With that said, LTFTs are supposed to be adaptations made during part load driving conditions, so I don't know if this is actually a problem, or if they can be ignored since the car wasn't being driven when this video was made.

By the way, with MHD you can monitor and log both STFTs and LTFTs yourself.

I don't see what he sees with the O2 sensors. They look to me to be fluctuating by about the same amount. Your log also shows the lambda/afrs following each other very closely.

He mentioned an intake leak again in the video. What does he think is leaking? An intake leak could be causing drivability issues, your 30ff and the woosh sound you're talking about, but those things in the turbo world would be known as boost leaks.

I'm a little lost to offer anymore advice here. Your 3 codes are common, but not at the same time and really don't seem related. If the shop doesn't get it fixed, do another log and this time include the STFTs, LTFTs, high fuel(rail) pressure and WGDCs for bank 1 and 2.

[Pavlo335]

Originally Posted by Emilime75

OK, so he's got his terminology wrong. What he replaced is what is known as an "inlet" and your N54 has 2 of them, one in the front to the front turbo and one in the rear of the motor to the rear turbo. I am just about positive that a leak anywhere in either inlet would not cause any issues aside from potentially allowing unfiltered air to get into your turbos and engine through the intake system...which is bad in the long run, but would not cause any drivability problems.

The exhaust leak is evident in the photo. You can see how the flange appears to have a gap at the gasket and the black soot from the exhaust gas leaking on the bottom. It looks like there are new nuts, but the studs on the downpipes look very rusty so they probably had trouble tightening things down. Curious if they now replaced the rusty studs with new bolts. FYI, those are not v band clamps. They are merely 2 flanges that are bolted together with a gasket in between them.

On to the video.

The additive mixture adaptations being "stuck" at 0 is a good thing. These are known as short term fuel trims, or STFT, and are the adaptations the DME is making with the engine at idle. Since he was showing those with the car idling in his shop, there is nothing wrong here.

The multiplicative mixture adaptations are a little suspect to me. These are known as long term fuel trims, or LTFT. I agree with him that they shouldn't differ the way they are and should be close to each other. With that said, LTFTs are supposed to be adaptations made during part load driving conditions, so I don't know if this is actually a problem, or if they can be ignored since the car wasn't being driven when this video was made.

By the way, with MHD you can monitor and log both STFTs and LTFTs yourself.

I don't see what he sees with the O2 sensors. They look to me to be fluctuating by about the same amount. Your log also shows the lambda/afrs following each other very closely.

He mentioned an intake leak again in the video. What does he think is leaking? An intake leak could be causing drivability issues, your 30ff and the woosh sound you're talking about, but those things in the turbo world would be known as boost leaks.

I'm a little lost to offer anymore advice here. Your 3 codes are common, but not at the same time and really don't seem related. If the shop doesn't get it fixed, do another log and this time include the STFTs, LTFTs, high fuel(rail) pressure and WGDCs for bank 1 and 2.

Hey man I just want to provide you with an update as the info you provided me helped a lot and I thought you might be wondering what ever happened with my situation

After bringing my car to him the second time and asking him to double check the work he did on the car the technician told me that there was an intake leak coming from the intercooler now and that needs to be replaced. I told him that I was going to order an aftermarket intercooler myself and that I would bring the car back to him when the part came in. When I got my car back it was so dirty and running so much worse than before that I decided to bring it to a different bmw specialist that a friend had recommended.

My car spent nearly a month at this new shop because they were so busy, but I had informed them about what the original mechanic had said and the symptoms I was experiencing (the loss of power, the wooshing noise etc.) and I also told them about that noise I heard when I initially drove the car after picking it up that had sounded like something had broken off and fell out from under the vehicle. I asked them to diagnose the vehicle as well as check the pipes and hoses and all the connections that were touched when the work was done.

They found that the inlet pipe that was replaced, which you had helped me determine was not the charge pipe, was completely disconnected and the bracket that is supposed to hold it in place was missing. They also confirmed the intake leak from the intercooler. They told me that there were ground wires that were so loose that they could be tightened by hand and that this work was so sloppy that they couldnt believe an actual shop did this. They fabricated a new bracket to secure the inlet pipe and I had them install a VRSF 5" FMIC along with a VRSF charge pipe and an HKS BOV. I finally have the car back and it runs much nicer however I do still feel there is a lack of power in high gears and I have to give it a lot more throttle input than normal just to pass someone on the highway. I did notice there is still an occasional hiccup at idle that seems to go away once the car warms up. I did a log but I was unable to add the STFT and LTFT parameters that you advised because I am logging using bimmergeeks protool and those were not an option. The car is still on a stock tune, I do want to get MHD so I think I will order that next and when it arrives I will take some logs including all of the parameters you have advised and post them up.

Here’s a picture of the leak in the old intercooler: https://www.e90post.com/forums/attac...1&d=1601343003

That was on the back side of the intercooler and the new shop was very skeptical of the leak and told me that it appeared as someone had hit it with a sharp tool. This would make sense as I had never experienced a 30ff code until I got it back after the work was done. Another thing they pointed out is that all of the splash guards are missing from the car and I will need to order new ones. Needless to say I'm never going back to that other shop in my lifetime.

Again man thanks for all of the accurate information you provided me with and helping me understand exactly what was going on with my car. I appreciate all of the advise I can get with this thing.