[nate16]

Here's my dilemma. I'm have a possible boost leak. I'm working on a tune with PTF and they've been awesome so far. However, I keep getting code 2c57 for a boost leak and have been trying to chase it down to no avail. The thing is, I can consistently boost to 18+psi in 2nd but in 3rd, boost maxes out at 14, falls to 10 quickly, and then I throw 2c57.

So far, I've replaced the lower charge pipe, regular charge pipe. Visually inspected the fmic and hot side fmic connection. Used starting fluid to check for vac leaks. No change.

Next on my list are boost solenoid, and thoroughly inspecting the hot side and fmic. If nothing, I will run a true boost leak test.

To me, I'm thinking psi is psi and if I can hit 18 in 2nd, it should be able to hold at least that much boost in other gears.

Has anyone experienced anything similar? Or have any recommendations? To me, it seems like a boost control issue, not a leak. I will try flashing a COBB ots map and see if I can replicate the issue however, those maps have lower boost targets anyways.

Right now, car is completely stock. I removed the BMS charge pipe to see if that was the problem but it wasn't.

I am going to be doing spark plugs this weekend too, the car has a tiny bit of rough idle and 80k miles. Not sure whether they've ever been done.

Thanks,
Nate

[JETmn]

Do a boost leak test. Most cars they put an adapter on the inlet of the turbo, but that isn't real easy to get to on ours. I plan on making an adapter for the sensor on the charge pipe, but haven't got around to it yet.

You have the o-ring on the charge pipe, right? That is the most common thing I see missed.

[nate16]

Yup, O ring is on charge pipe and I swapped the pipe back to the stock to verify it wasnt the pipe. I'm going to probably end up doing a real boost leak test. I am grabbing a replacement solenoid tomorrow and swapping that out too. At this point, I've replaced pretty much the whole cold side from FMIC to TB.

Next steps/Possible Leak Sources:
Boost Solenoid + Vac lines
Diverter Valve
Hot Side Piping
FMIC Itself

Can anyone think of anything else to check?

[Andrewe92]

I'm not bringing much to the table here, but why don't you have a shop do a white smoke test.

[nate16]

If all else fails, I will do a true boost leak test. I'll probably build a tester and do it myself. Generally, smoke tests are best for finding vacuum leaks because the testers don't usually go above 3-5psi which quite often won't show a boost leak unless it's huge.

[Mike@N54Tuning.com]

Check the CP to FMIC connection (Cold Side)

Mike

[nate16]

Originally Posted by Mike@N54Tuning.com

Check the CP to FMIC connection (Cold Side)

Mike

Hi Mike,

I've already replaced the full cold side, upper charge pipe and lower charge pipe, problem still persists.

Thanks,
Nate

[604.e92]

Did you buy a oem lower charge pipe?
There seems to be a leak between my lower chargepipe and the ic but I don't want to spend 300 on a oem lower charge pipe when i will upgrade the intercooler soon.
Is there a gasket between?

[nate16]

Yes I did buy an oem lower charge pipe, I have my old one I'll sell you, mine just has the little clip broken off so I used the new one.. I believe there's an o ring there -- If your upgrading soon you probably don't want it but figured I'd offer.

[skua]

Check the vacuum cannisters if it's an n54 engine you have. I had similar issues as you did, no leaks from the charge pipes however the vacuum cannister nipple connecter was practically snapped with the hose connected to it which was the cause of a lot of 30ff boost pressure errors for me. Installed aftermarket stainless Steel ones and she's on the money now

[trixdout]

Originally Posted by nate16

If all else fails, I will do a true boost leak test. I'll probably build a tester and do it myself. Generally, smoke tests are best for finding vacuum leaks because the testers don't usually go above 3-5psi which quite often won't show a boost leak unless it's huge.

You can make your own. I'm i the process of doing so. Grab an old computer power supply and a glow plug from auto zone and baby oil. Rig up a container for an in and out compressed airline and put the glow plug into the container. Wire it to the power supply and hook it up to the intake system. Cap off the exhaust and run the desired pressure you want. (preferably go higher than the boost you run to make sure your can handle it)