[924er]

Hello guys, so this morning driving to work I did a 4th gear pull on my 335i DCI/FMIC 5in running stage 1+ drive, suddenly I go into limp mode half engine light. Reseted the codes, it went away but I was afraid to go fully wot but I did give it some gas and I can hear a whooshing sound I never heard before but no codes.

Pulled up codes p30ff(something about pre boost pressure to leak from pressure line; error on loader 2)
Misfires cyl 1,3, and 4.

Checked for cp leak and DV leak looks normal.

I flashed my car back to stock, drove it around went WOT multiple times with no codes at all. I want to take it to the dealer but there aren't gonna be any codes cuz cobb clears them when you uninstall it.

I haven't installed cobb since then.

So my next step is to check for leaks at an Indy shop even tho I don't trust then I don't the tools.

Is it possible this could just be a hiccup but no actual leak? Even tho I do hear an abnormal sound I could be trippin.

Anyone had this issue before?

Thanks

[Jeff@TopGearSolutions]

Boost leaks are a very common issue.

Anyone with an aftermarket FMIC typically has a small leak right at the intercooler connections so be sure those connections are squared up with the pipe and tighten the clamps a little more.

A prerequisite to anyone tune is to be sure your hardware and maintenance is up to date.

That includes replacing your spark plugs if they have over 25,000 miles and making sure you have a strong HPFP high pressure fuel pump, LPFP Low pressure fuel pump, coilpacks and injectors. (To name a few). If any of these are on the way out they will be more susceptible to failure once boost is increased.

Visually things may appear normal but you really can't see a boost leak unless it's an obvious disconnect or tear. Things expand under boost pressure and that's why boost leaks are hard to find.

http://www.e90post.com/forums/showthread.php?t=631829

How many miles are on your car?

The only way to test for leaks is with a boost leak pressure test. Otherwise you will end up replacing parts blindly until you find the leak.

Start with the obvious first like checking for obvious connection issues, tightening clamps, looking for tears, checking the boost solenoids, boost tubes, ETC

Then either get a professional boost leak test done or start with the cheap fixes first like replacing all the vacuum lines. Unfortunately with 30FF codes and boost leak codes nobody online can tell you what's leaking since their are so many variables and things that could cause the leak.

The misfires are not a glitch and I'm willing to bet your spark plugs have over 25,000 miles on them.

[924er]

Actually spark plugs were changed 1,600 miles ago, I change them every 25k cuz I'm always tuned. I don't understand how 3 can randomly misfire when it was running perfect befote

Why is it that I'm getting multiple cylinder misfires, is this related to the boost leak??
Can the boost leak be a glitch?

And why doesn't my car have a boost leak when I'm running stock, I can rape my car and have no codes. Car runs smooth.

[924er]

Can a service advisor notice a cobb tune by just plugging in your key to see what service is due? Or is that all up to the tech ? Just a random questions thanks

[Jeff@TopGearSolutions]

Originally Posted by 924er

Actually spark plugs were changed 1,600 miles ago, I change them every 25k cuz I'm always tuned

Why is it that I'm getting multiple cylinder misfires, is this related to the boost leak??

And why doesn't my car have a boost leak when I'm running stock, I can rape my car and have no codes. Car runs smooth.

Stock has about 8 PSI, thats 8 pounds of pressure per square inch.

Tuned can reach nearly double that say 13-16 Pounds per square inch on all boost related hardware. By no accident increasing pressure per inch will expand hardware and something that maybe is not leaking at 8 psi can certainly leak at 13+.

How many miles on the car?

Have you ever had a valve cleaning?

Have you ever replaced any injectors?

Have you ever cleaned the vanos solenoids?

Have you checked the spark plug gap?

Have you checked the spark plugs for fouling (Could be an indication of injector issue).

Again, all we can do here is tell you things to check. You need to start with the basics.

[924er]

Good Informantion Jeff. Makes perfect sense

The car has 30k miles never had a valve clean yet. Injectors were replaced per recall at 20k at dealer. Never cleaned VANOS

[924er]

Is it possible I'm getting these misfires because of the sudden boost leak?

I never had any issues for the past 4 months. Plugs are still fresh. No misfires or boost leak on stock tune

I don't know where to start, should I fix the misfire or focus on a boost leak?

Originally Posted by 924er

I don't know where to start, should I fix the misfire or focus on a boost leak?

Well, you could start by searching the forum...you are not the first person to throw a code while running a tune.
http://www.e90post.com/forums/showthread.php?t=546560

[924er]

I understand but it's a simple question, is it possible for a boost leak to throw multiple misfires. I wish I can just take it to the dealer but cobb clears all my codes and I cannot replicate it. I don't want to take it to an Indy they are thieves here in cali

[924er]

So far from what I searched. Ppl either have misfires or boost leaks but not both in one incident. Mine happened to be both misfire and boost leak at the same time. I'm not tryna be one of those lazy ppl that don't search cuz I been searching lol

I know misfires get solved using the plug/coil/injector/vanos/carbon/hpfp/lpfp sequence but I don't see boost leak causing it. So now I'm starting to think I got 2 different issues with their own sources

[gtaccord]

I would just go ahead and replace your spark plugs. Having misfires in multiple cylinders is more indicative of spark plugs imo.

As far as the boost leak goes just check all the vacuum lines first as well as the charge pipe, dv and intercooler connections. It is most likely in one of those areas.

[Jeff@TopGearSolutions]

Originally Posted by 924er

So far from what I searched. Ppl either have misfires or boost leaks but not both in one incident. Mine happened to be both misfire and boost leak at the same time. I'm not tryna be one of those lazy ppl that don't search cuz I been searching lol

I know misfires get solved using the plug/coil/injector/vanos/carbon/hpfp/lpfp sequence but I don't see boost leak causing it. So now I'm starting to think I got 2 different issues with their own sources

A boost leak is a boost leak no matter how you cut the slice. Fix the boost leak.

If you fix the boost leak and still have a misfire then you have more then one problem.

[924er]

Ahh okay well that makes sense, I'll attend to the boost leak first .

I'm dropping the car off at the stealership tomorrow, they are going to be inspecting for vacuum leaks however my car won't show any codes with the stock tune. Do BMW dealers go by codes or do they actually troubleshoot the issue. I have heard many stories on the forum of dealers refusing to check issues only because there aren't any codes. I think that's stupid

[Jeff@TopGearSolutions]

Originally Posted by 924er

Ahh okay well that makes sense, I'll attend to the boost leak first .

I'm dropping the car off at the stealership tomorrow, they are going to be inspecting for vacuum leaks however my car won't show any codes with the stock tune. Do BMW dealers go by codes or do they actually troubleshoot the issue. I have heard many stories on the forum of dealers refusing to check issues only because there aren't any codes. I think that's stupid

This is not really a job for a dealership since you do not have any codes and it's not repeatable on stock tune. You are likely wasting your time bringing it to dealer since there are no codes and not repeatable on stock tune.

Since it only happens on a tuned vehicle and your vehicle is modified you also might be setting yourself up to be red flagged and warranty voided. Just being honest. Of course EVERY dealer is different.

You should seek an independent shop or pop the hood yourself and check connections and lines.

[secretsquirrel]

If you haven't done so recently, spend 20 mins and $5 and replace your vacc lines. Doing so resolved my 30FF codes. I was pulling 8-10psi before id get codes.

[Jklad]

Have you checked your connections yet? The obvious ones. Both times I had a boost leak they were plain as day once I examined:

One was the c-clip on the cp to tb was not pushed all they way into the groove on both sides. This caused a boost leak code only when tuned and holding sustained boost in a high gear - the stock tune did not produce enough pressure, but the tune produced just enough to cause the cp to shimmy a bit on one side and leak boost under high sustained load.

Second time was my top driverside IC connection popped right off - needed to be clamped tighter.

Chances are you misfires should e handled as a seperate isolated issue, if it returns once you find the boost leak.

[924er]

Right I understand, but the thing is I'm cool with the actual technician BMW. He is the one that installed my FMIC and said he would always work on my car however I don't really know the SA. So I'm planning on bringing my car in with cobb installed do u think the SA would catch the tune just by plugging in the key to the computer to check service intervals. I definitely don't want to risk it.

But thanks everyone for all the input esp Jeff Ur always a good help

[924er]

Originally Posted by secretsquirrel

If you haven't done so recently, spend 20 mins and $5 and replace your vacc lines. Doing so resolved my 30FF codes. I was pulling 8-10psi before id get codes.

Is that really all it takes to replace the vacuum lines?! The ones from the DV look really hard to get to

[924er]

Originally Posted by Jklad

Have you checked your connections yet? The obvious ones. Both times I had a boost leak they were plain as day once I examined:

One was the c-clip on the cp to tb was not pushed all they way into the groove on both sides. This caused a boost leak code only when tuned and holding sustained boost in a high gear - the stock tune did not produce enough pressure, but the tune produced just enough to cause the cp to shimmy a bit on one side and leak boost under high sustained load.

Second time was my top driverside IC connection popped right off - needed to be clamped tighter.

Chances are you misfires should e handled as a seperate isolated issue, if it returns once you find the boost leak.

Oh ok good information thanks a lot. I still think the misfiring is secondary to boost leak but I won't know until I fix the leak. My plugs are still new. Injectors are the latest along with HPFP. Car only has 30k miles

[secretsquirrel]

Originally Posted by 924er

Is that really all it takes to replace the vacuum lines?! The ones from the DV look really hard to get to

Taking off the cowls and engine cover is about 10mins of work. Taking off and replacing the lines take about 2-3 minute a piece. Just slit the lines at the connections with a box cutter and take the hoses off. DONT pull hard, you don't want to damage the plastic nipple by being too rough. Slide on the new hoses. 6' of it can be found at PoopBoys for $5. The inner diameter of the hose is 5/32". If your car is more than a few years old, this update should be done as preventive maint.

[924er]

UPDATE: ok so I reinstalled cobb to stage 1 sport (last time was stage 1+) and I'm boosting no more than 11psi it used to be around 14-17psi and I can hear a loud Whoosing sound coming from the turbos and I'm not getting any codes or engine malfunction. I did multiple 3rd gear pulls. I no longer hear my DVs when I let off the throttle so that is telling me boost isn't reaching it I think. It's really odd how it's not giving me any codes just lower boost and louder sounds

[924er]

Originally Posted by secretsquirrel

Taking off the cowls and engine cover is about 10mins of work. Taking off and replacing the lines take about 2-3 minute a piece. Just slit the lines at the connections with a box cutter and take the hoses off. DONT pull hard, you don't want to damage the plastic nipple by being too rough. Slide on the new hoses. 6' of it can be found at PoopBoys for $5. The inner diameter of the hose is 5/32". If your car is more than a few years old, this update should be done as preventive maint.

Thanks for the info man. So there are 6 hoses total? I wish there was a diy around here for thay