[gde061]

Hello - I just bought a 2008 335xi... first entry into the world of BMW's. It came set up with a bunch of mods, most noticeable the catless downpipes, so the fuel smell has been there since I test drove it; also has after-market intakes, intercooler, and blow-off valve.

The senario is that the car ran well up to now -- test drive, and about 20-30 miles since I brought it home. It's a manual 6, and finding / getting going in first is a little finicky, but I chalk it up to the clutch being a little hard. Anyway, yesterday at cruising speed on the highway, I put the pedal down to boost ahead and cut into a gap, and I felt a hesitation after the turbo had kicked in, then it kicked in again and seemed fine the rest of the way home. I wouldn't say for sure it was a misfire, but could have been

This morning in the driveway, at about 45-F air temp, when I started up there was a fair amount of backfiring and idling rough. The "check engine soon" light is not on when running (only on when I first put the key in "accessory" mode)

I was thinking maybe I should change the plugs. I found this video helpful to explain what might be up since there were some things done to modify the car just like he was talking about.

The previous owner said he had a JB4 hooked up but started to see problems, so took it off and the problems went away. Given that it ran fine for me in the test drive, I took him at his word.

I know very little about tuning. I planning that this car is going to be a gateway for me to learn more about tuning, etc. I don't really know how tuning works, but I've seen some threads where people say the JB4 isn't a real tuner so I'm a little confused. Next stop when I have free time is going to be the "intro to tuning" thread.

In the meantime, I'd love to get some input on what you think might be the issue causing the hesitation and the backfires.


**UPDATE -- I was able to get the freeze frame data from the code ... I'm new to this stuff, so any interpretive / diagnostic help is greatly apprecaited ***

ECT 81 F
STFT B1 -3.1%
LTFT B1 0%
STFT B2 3.9%
LTFT B2 -7%
Intake manifold pressure (MAP) 23 inHG
Engine RPM 1179
speed 0
spark adv -27 deg
IAT 75 F
Absolute Throttle position (TPS) 18%
Relative Throttle position 9.4%
Run time 11 sec
Fuel Pressure 2467 psi
barometric pressure 29 inHg
Ambient temp 73F
TPS B 18.4%
Acce Pedal D 14.1%
Acc pedal E 14.5%
Command throttle acuator 10.2%
Long Term Fuel Trim bank 1 (O2 sensor) -9.4%
Long Term Fuel Trim bank 2 (O2 sensor) -10.2%

Load value 191.4%

So from the Freeze Frame data, which I dont' really know all that much about, it looks like something happened just after ignition that made the load spike. I don't really understand what would cause the load value of 191.4% that would relate to carbon build up... or maybe the misfire affects what the computer is using to calculate the load?

On the other hand, the long term fuel trim numbers look like one bank is being leaned out by the ECU much more than the other (i.e., running rich by default?) At the occurrence of the fault, the bank with cylender 4 was being trimmed lean, white the other bank was running lean and being trimmed rich. Could represent leaking injector in bank 4 I suppose...

*****



Thanks!

[msjt]

Probably leaking injectors. The fuel pools up and causes the stumbling when you first start it up.

[gde061]

Originally Posted by thelightning

We need some kind of automated reply system for every person under 10 posts that creates a new topic saying: The injectors probably need to replaced.

So sorry to impose on you... but thanks for the insight anyway.

Anyway, this morning I warmed it up, it was a little rough but not backfiring a badly as yesterday. Shut it down and went inside for breakfast... came out and started up and now I have the check engine light on. The code is too many misfires on cylinder 4 (had it read at Autozone).

From what I can tell just listening, the problem seems to be worse when the engine is cold, especially with lower morning temps -- I won't call them cold of Ohio.

So as I think about what I'm going to be investing in for this car, it would be very helpful if anyone could point me in the right direction for what kind of electronic reader / etc. I need to get to reset the engine code, since I won't even be able to get plates with that light on.

Thanks.

[b92]

Originally Posted by gde061

So sorry to impose on you... but thanks for the insight anyway.

Anyway, this morning I warmed it up, it was a little rough but not backfiring a badly as yesterday. Shut it down and went inside for breakfast... came out and started up and now I have the check engine light on. The code is too many misfires on cylinder 4 (had it read at Autozone).

From what I can tell just listening, the problem seems to be worse when the engine is cold, especially with lower morning temps -- I won't call them cold of Ohio.

So as I think about what I'm going to be investing in for this car, it would be very helpful if anyone could point me in the right direction for what kind of electronic reader / etc. I need to get to reset the engine code, since I won't even be able to get plates with that light on.

Thanks.

First off, do you know if your car has a tune? If it has a JB4 or MHD then you should get the supporting hardware to read from those.

If you have all of those mods and no tune, then you should definitely look into either of those as your car is not taking advantage of those modifications without one, but you will be able to read & clear codes from either. I recommend MHD and it is also cheaper, especially if you already own an Android device. If you don't have a check engine light for your DPs then it's very possible you have MHD software installed, as that clears that code automatically. There are other ways this could be cleared automatically, though.

There is also another app called My Carly or something like that, it's basically a coding interface for things like seatbelt warning, etc. but can also read & clear fault codes. This is available for Android and iOS: https://www.mycarly.com/product/bmw-app/

Both MHD and Carly require a cord to connect your device to your car though, this can be done for cheap via a DCAN cable and adapter from Amazon or the bluetooth adapter offered by Carly. I have the bluetooth adapter myself since Carly requires it for some coding modules, which is really just a bullshit paywall since I already spent ~$50 on the app but whatever. To my knowledge, the Carly bluetooth adapter will not work with MHD.

[gde061]

From what the prior owner said, he used to have a JB4 hooked up to it, using a laptop, and was running it with something like 12 psi boost. He was not so specific about what kind of problems the tune was causing, but he said he thought it was from the connection and so he took it off.

The way he explained it, I interpreted that to mean he set it back to stock settings. What I saw was consistent with that, as the fuel gauge doesn't show boost. From what I read, as I piece through this, if you are doing some major ECU re-writes with the wrong cables, stuff can get fragged, for example, if signal corruption happens.

I hate to think that could have happened... is there a way I can check that? I could probably ask him if he has the original tune file that he started from when he got the car, but I'm figuring that's what he put back on it before he sold it, and then I'm going to need to get the JB4. Or for peace of mind I suppose getting the stock file from MHD is the only way to start fresh?

[b92]

Originally Posted by gde061

From what the prior owner said, he used to have a JB4 hooked up to it, using a laptop, and was running it with something like 12 psi boost. He was not so specific about what kind of problems the tune was causing, but he said he thought it was from the connection and so he took it off.

The way he explained it, I interpreted that to mean he set it back to stock settings. What I saw was consistent with that, as the fuel gauge doesn't show boost. From what I read, as I piece through this, if you are doing some major ECU re-writes with the wrong cables, stuff can get fragged, for example, if signal corruption happens.

I hate to think that could have happened... is there a way I can check that? I could probably ask him if he has the original tune file that he started from when he got the car, but I'm figuring that's what he put back on it before he sold it, and then I'm going to need to get the JB4. Or for peace of mind I suppose getting the stock file from MHD is the only way to start fresh?

JB4 is a standalone unit that plugs into the stock ECU, so nothing is coded to your car. By uninstalling a JB4, your car is reverted back to stock.

It is extremely hard to screw something while tuning using the popular methods (JB4, MHD, etc.), there are very few instances of someone screwing up and causing damage to the DME. Given the 'plug n play' nature of the JB4, this is pretty much impossible.

I would wager the reason the JB4 was removed was because the car was misfiring bad, and given the availability of information around misfires he probably took all the steps in remedying up until the expensive one, injectors (>$1000).

Given your symptoms, this is the likely culprit.

[gde061]

Ah, thanks for explaining how the JB4 works. So a MHD tune involves changing the ECU? In working through the stickies here, I got to the one with the big spreadsheet with JB4, Cobb, and a few others. I didn't see MHD, so I'm guessing that is in a more advanced class of "coding" vs. "tuning"?

Also I got to the sticky on misfires. I think I will work my way through that step by step, just to get more fThere is someone selling
amiliar with the car... although if it's the injectors then the plug residue might be pretty obvious on step 1.

Sorry to sound like a noob, but I was reading this thread about walnut blasting vs. injector cleaner, and I understand why fuel additive won't do anything for intake valves with DI, but I guess I wonder if something like Seafoam can be used as a band-aid for an injector that is having issues. Like maybe the seller had some additive in the fuel to prevent misfire / backfire, and so after a couple drives burning up the 1/4 he set me up with, I gas up without the chemical additive, and, viola, misfire. Just kinda curious what people think -- not like I'm going to make a big deal about it with the seller. Just want to get my head around what I might be up against.

Also kinda wonder if maybe the walnut blasting might be needed. I got basically no maintenance records as the guy said he did all the work himself, but I think he would have mentioned about it if he had walnut blasted it. There's no catch can, and it's at around 80K miles. I guess I'm going have to open up the intake manifold to physically inspect for carbon deposit...?

[BM3Rrrr]

Originally Posted by gde061

Ah, thanks for explaining how the JB4 works. So a MHD tune involves changing the ECU? In working through the stickies here, I got to the one with the big spreadsheet with JB4, Cobb, and a few others. I didn't see MHD, so I'm guessing that is in a more advanced class of "coding" vs. "tuning"?

Also I got to the sticky on misfires. I think I will work my way through that step by step, just to get more fThere is someone selling
amiliar with the car... although if it's the injectors then the plug residue might be pretty obvious on step 1.

Sorry to sound like a noob, but I was reading this thread about walnut blasting vs. injector cleaner, and I understand why fuel additive won't do anything for intake valves with DI, but I guess I wonder if something like Seafoam can be used as a band-aid for an injector that is having issues. Like maybe the seller had some additive in the fuel to prevent misfire / backfire, and so after a couple drives burning up the 1/4 he set me up with, I gas up without the chemical additive, and, viola, misfire. Just kinda curious what people think -- not like I'm going to make a big deal about it with the seller. Just want to get my head around what I might be up against.

Also kinda wonder if maybe the walnut blasting might be needed. I got basically no maintenance records as the guy said he did all the work himself, but I think he would have mentioned about it if he had walnut blasted it. There's no catch can, and it's at around 80K miles. I guess I'm going have to open up the intake manifold to physically inspect for carbon deposit...?

MHD is probably the most popular tuning software on here, super easy to install and very user friendly. There is huge thread about it on here. It does not involve changing the ecu. I would get it and use it to determine what codes you car is throwing, better then taking it to AutoZone every time.

See description here: https://www.e90post.com/forums/showthread.php?t=1096242

If it hasn't had a walnut blast it will definitely need one, but yes if you are unsure then you would need to get a look at the intake valves.
Also its worth while to check the plugs and coils and replace if needed, these can cause misfire issues as well

[gde061]

Thanks for the information.

I suppose I will plan for walnut blasting. The blasting tanks from Harbor Freight look downright cheap considering this is a 30K maintenance. But are they any good...

I want to bring up Seafoam again. There are a lot of videos specifically with BMW's "cleaning" with Seafoam. Two things: in the videos, they attach it just after the MAP sensor on what looks like the cold air intake, but I read somewhere here that you need to spray it in with the charged air after the turbos... Which is correct?

Second, the consensus here seems to be Seafoam might get you a nominal bit of improvement, so probably better to do a real cleaning, but either way Seafoam won't do any damage (other than hydrolocking adding the liquid wrong). But if Seafoam is breaking down carbon deposits, then maybe some big chunk could breaks free, not get burned up immediately in the cylinder, and get sucked into the turbos and frag them? I feel compelled to ask -- I suppose that's why they say "drive aggressively" after doing the Seafoam, but frankly that's easier said than done in my neighborhood.

[wrrush]

If you need a walnut blastin attachment let me know i have one i never used i can sell you for $25 plus shipping

[b92]

Originally Posted by gde061

Thanks for the information.

I suppose I will plan for walnut blasting. The blasting tanks from Harbor Freight look downright cheap considering this is a 30K maintenance. But are they any good...

I want to bring up Seafoam again. There are a lot of videos specifically with BMW's "cleaning" with Seafoam. Two things: in the videos, they attach it just after the MAP sensor on what looks like the cold air intake, but I read somewhere here that you need to spray it in with the charged air after the turbos... Which is correct?

Second, the consensus here seems to be Seafoam might get you a nominal bit of improvement, so probably better to do a real cleaning, but either way Seafoam won't do any damage (other than hydrolocking adding the liquid wrong). But if Seafoam is breaking down carbon deposits, then maybe some big chunk could breaks free, not get burned up immediately in the cylinder, and get sucked into the turbos and frag them? I feel compelled to ask -- I suppose that's why they say "drive aggressively" after doing the Seafoam, but frankly that's easier said than done in my neighborhood.

I wouldn't waste your time or money with Seafoam. It doesn't come anywhere close to the effect of walnut blasting.

I went with the Harbor Freight kit, there are some shopping lists around these forums that list everything you need to order for the job.

I did it myself, took about 6 hours in total by myself but that was mostly taking the car apart and putting it back together. If I had to do it again it would take me about 3.5. Total cost of the kit was a little over $200 all-in, including carb cleaner and such. Cheapest rates around here are about $300, with shops charging north of $400. Dealership rates are astronomical, but they do have the best tools for the job.

[gde061]

Just want to update this thread with the latest info. I had some Murphy's Mystery Oil left in my garage so I decided to give it a shot. I added it to the tank and the misfire became less frequent, but also it's definitely worse in colder, damper weather. After a few days, the check engine light went off. I had the first check engine again this morning -- cold, drizzling rain -- when I stalled out in my driveway (my fault... foot slipped off the clutch).

Here's the odd thing... after that stall, it started up on first fire, but it was idling something aweful and the check engine light was on. I went about 100 yards, and was like, I can't drive like this... I'm going back and take my wife's car. But just for kicks, I shut it off, and restarted it again. That time the check engine light stayed off, and the car seemed to idle much better, maybe a little rough, but nothing like immediately before. I went down the road a bit, keeping it in the sweet spot of the torque band, and by the time I got where I was going, it was purring like a kitten.

One more thing -- not sure if this is related or not -- but after adding the Murphy's Oil, the stench of unburnt fuel that I chalked up to the catless downpipes seemed to get a lot less pronounced. I can't even smell it anymore unless I'm idling in one spot for a few minutes. Previously, it was immediate -- every time I stopped at a light I had to crack the windows right away. Maybe I just got used to the smell... but I'm curious if anyone else with a catless setup has had similar result with a fuel additive like Murphey's Oil to reduce the richness of the exhaust?

[Koolsilver]

Don’t waste your time with any of the snake oils they don’t do anything. If you notice a difference it’s placebo effect. As others have said walnut blasting would be a good idea but that’s probably not going to resolve your misfire. Start by getting a DCAN cable they can be had for around $20 on amazon you will also need a micro usb OTG adapter should be around $5 on amazon. If you already have an Android device you’re good to go if not borrow one or buy the cheapest one you can find, there are plenty of cheap ones out there. Now you can download MHD for free on the android and read the check engine lights for free.

Now start with the easy stuff for the misfire the spark plugs and coil packs. You said the code called for misfire cylinder 4 so take the spark plug and coil pack out of that cylinder and swap it with another say swap cylinder 5 spark plug and cylinder 3 coil pack. Once the code come back see where it has moved to if 5 bad spark plug, if 3 bad coil pack, if 4 something else is going on most likely at that point injectors.

[gde061]

I appreciate your view of "snake oils", and the detailed explanation how to nail down where the misfire is happening the right way.

I'm just reporting what I actually observed. And it was Marvel Mystery Oil, not "Murphy's" -- oops. I know the snake oil products over-market and misrepresent what they do. In reality, they do something... and in some cases it's something BAD. From my experience with vintage bikes, Marvel Mystery Oil did cut down backfires on a carbeurated engine for me when there were issues from gum-up. I'm talking about applications where finding the kit to re-jet the carb would have cost more than I the bike.

And also everybody's youtube favorite, SeaFoam, can actually burn off rough carbon to a degree to get better valve sealing -- it might be a carbon-to-carbon seal, but it's better than no seal -- but it can also screw things up. I would never add it to my crankcase oil, and the idea of bits of carbon being chemically blasted off and heading downstream with the exhaust gases of an engine running under heavy load ("drive aggressively" is what the instruction say) makes me hesitate to use it with a turbocharged engine.

From what I can figure on my own, MMO has mostly mineral oil and maybe even some lard. I suppose one upside might be better lubrication of the fuel pump. The downsides would seem to be that (1) it can gum stuff up itself, and (2) it has poor heat dissipation compared to gasoline. There is a documented case where MMO gummed up a turbocharged aircraft engine. That bothers me and I would of course prefer to get under the hood and start a proper trouble-shoot, but real life intervenes and that's why the shelves stay stocked with snake oil band aids, and also why gas at the pump already comes with additives claiming it does the same stuff: Cf. Stuff article When people are worried about breaking their engines, they push "anti-knock". When people are worried about global warming, the push "cleaner burning". So if those claims coming from big fortune 100 companies are to believed, fuel additives can do everything from fix your engine to save the Earth! And my Great-auntie is the Queen of England.

[gde061]

Sorry to double post, but I added the freeze frame data to the first post. If one cylinder bank is being leaned and the other is being riched, does that support a faulty injector on cylinder 4 (the bank that is being leaned out)?

Also I can't seem to find data on the total cylinder misfire count. Is that typically not stored in the computer... i..e, only visible in live data?

Thanks