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Herbmiester

335i boost leak challenge.

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Can't clearly see a boost leak there. 2nd gear is too fast for a good reading. There's a throttle closure half way causing the boost to drop, I think that's because your traction control was triggered.

Would be easier to see what's going on if you can manage a 3rd gear pull, and hit the DTC button to reduce traction control (I wouldn't turn it off, but if you're brave enough...),

No timing corrections, I believe that means your spark plugs are fine, lol.

If you can get a 3rd gear pull maybe post in the e90post MHD thread for more opinions. 

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Log clearly shows a massive boost leak the target and actual boost should match. Usually you get all these issues after you tune a 335i will be interesting to see your patience with the car over time. You would be wise to learn to do stuff for yourself esp something straightforward as a boost leak as this could end up being an expensive car to maintain. 

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Yeah will try for a 3rd gear pull, but that means I have to go illegally fast.

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Yup find a quiet road turn off all electronic aids and floor it in 3rd shift at 6k to 4th keep going to get a proper log 

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Just now, jin108 said:

Log clearly shows a massive boost leak the target and actual boost should match. Usually you get all these issues after you tune a 335i will be interesting to see your patience with the car over time. You would be wise to learn to do stuff for yourself esp something straightforward as a boost leak as this could end up being an expensive car to maintain.

Yes I have the charge pipe and valves as mentioned and having looked at the other likely places I suspect it's there. Will fit these parts over the next few days and re log. I think saying its straightforward is a bit unfair as 2 workshops were unable to find the fault.

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Firstly, 1psi difference is a nats fart in the scheme of things.

Secondly a boost leak is not the only thing to cause low boost, you may be chasing shadows.

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Just now, Herbmiester said:

Yes I have the charge pipe and valves as mentioned and having looked at the other likely places I suspect it's there. Will fit these parts over the next few days and re log. I think saying its straightforward is a bit unfair as 2 workshops were unable to find the fault.

Yeah sorry its not quite straightforward but it is time consuming which is why its better to try figure out yourself rather than getting a shop to do it. Another thing to check are your vacuum cans i had a leak on one of them. But betting its your diverter valves based on what you already said earlier. 

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Just now, polley said:

Firstly, 1psi difference is a nats fart in the scheme of things.

Secondly a boost leak is not the only thing to cause low boost, you may be chasing shadows.

And that is the issue, everyone has a different opinion, so I will upgrade the pipe and valves as I would want to do this anyway when I load an MHD map. 

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1 minute ago, jin108 said:

Yeah sorry its not quite straightforward but it is time consuming which is why its better to try figure out yourself rather than getting a shop to do it. Another thing to check are your vacuum cans i had a leak on one of them. But betting its your diverter valves based on what you already said earlier. 

Yeah I have checked the cans and replaced the vacuum hoses with silicone hoses, the hose on the front turbo was cracked and at that stage I thought I had found the problem but alas no. 

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To be clear the only reason the shops did the work is that the code only showed up after the intake ports were cleaned. I made it clear that it wasn't doing it previous to them doing the clean. Whether it was just a coincidence or a contributing factor I can't say, but they removed and re-installed the manifold twice afterwards in case that was the issue. I still wonder if that is somehow causing the issue. In any case it will have a lot of new parts on it when it finished. :( 

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The ideal gear to log in is 4th but near impossible. So third is the next best, but yes logging is hard work unless you live in the country.

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Youre also still relying on the stock boost sensor, are you sure its reading correctly?

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Well all I can do is use the stock sensor as that's all MHD will read. 

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1 hour ago, BreakMyWindow said:

Maybe best to log it on a dyno? An hours worth of time on one could be a lot cheaper than a court hearing...

Easier said than done, have approached a couple and if its not there tune they turned me away.

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Get a vacuum gauge and plug it in directly with a t connector and long hose can watch it when going for a pull. You can then know for sure if there is an actual boost issue or just a sensor. And double check the manifold and CP are seated correctly since you only had this issue after the intake blasting. Best practice is to replace the manifold gaskets so another thing to check as well. 

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Just do a 3rd gear log before you bother with all that...

The target boost drop is like due to the throttle being cut by the traction control, don't get hung up on that before getting a better log.

Edited by Matth5
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The manifold has new gaskets and I may well fit a manual pressure gauge and do a check should the charge pipe not fix the issue. The reason is simple the FF30 fault code is now pretty well understood and as the CP and DV's are known weaknesses I will just replace them as they both struggle when boost is raised above stock and I intend to do this, 300 hp is not enough for this HP junkie. Road vs Drag car is irrelevant in this test as the it is only when accelerating constantly at full throttle as you would at a drag strip does this occur, in a on/off throttle situation like the majority of road driving it does not occur. . In fact a drag strip would be the perfect place to log the data. 

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3 minutes ago, Matth5 said:

Just do a 3rd gear log before you bother with all that...

The target boost drop is like due to the throttle being cut by the traction control, don't get hung up on that before getting a better log.

Yes that makes sense.

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4 hours ago, mattone74 said:

Easier said than done, have approached a couple and if its not there tune they turned me away.

I've used this company before for 1 hour of troubleshooting on the dyno before. They also hosted a bimmersport dyno day back in 2014 for us.

People seem to think dynos are just for checking Max Power and torque output or for tuning. They're also a useful troubleshooting tool.

http://www.mcrautomotive.co.nz/

I paid $85 + gst for 1 hour of time.

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2 minutes ago, BreakMyWindow said:

I've used this company before for 1 hour of troubleshooting on the dyno before. They also hosted a bimmersport dyno day back in 2014 for us.

People seem to think dynos are just for checking Max Power and torque output or for tuning. They're also a useful troubleshooting tool.

http://www.mcrautomotive.co.nz/

I paid $85 + gst for 1 hour of time.

Awesome,I will give them a whirl

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Based on what I have read on the US boards slow acting plastic OEM diverter valves are contributing to the boost response and the overshoot. The leak; well I suspect again DV or CP or both.  CP has arrived so i will try and fit it tonight. 

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Boost builds up very slowly, my feeling is something is inhibiting it from building boost in the first place, not a leak. 

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