[bL79]

Ok just got a 2015 E84 X1 35i. N55 with PWG I'm pretty sure. ~117,000 mi

Installed the Evolution Racewerks CP and VRSF 7.5HD FMIC over the weekend.

Have the car on XHP (stg3) and MHD (stg 2) OTS tunes.

Filled up with some ethanol to make ~E30 today and try the Stage 2 MHD E30 maps. Also decided it was probably a good idea to look at logs finally. I did a quick before and after but realized I'm far short of boost targets.

What's curious to me is the WGDC doesn't seem to much exceed 50%. If I had a boost leak shouldnt I expect the WG and thus turbos to be commanded to near max?

After some reading and inspection I'm pretty suspicious of the boost solenoid vacuum system. I can pretty easily crush the fabric covered line with my fingers. Could that cause the issues seen? I can see the boost solenoid installed is Pierberg, were they OE or does that indicate it was replaced at some point?

https://datazap.me/u/bl79/x1?log=0&data=3-4-14-19

[wrevilo]

A lot of detail is over my knowledge, but I am certain the OE solenoid is Pierburg. I recently had mine replaced and used a Pierburg unit.

[bL79]

That's helpful, thanks.

Debating if I should R&R the solenoid and hoses or just the suspect fabric covered hose. The fabric wastegate hose routes over the exhaust manifold so seems like an insulated option is desirable.

Doesn't seem like that difficult a job but I'm not super looking forward to wresting the hose off the WG or solenoid nipples.

I guess sometimes when the solenoids fail they make a pretty obvious noise but I haven't noticed anything like that.

Hmm maybe Ill try to pull the line off the solenoid and vacuum test it with a mityvac

[swellengear]

Always a good idea to replace the old vacuum lines with the upgraded silicone options. It's cheap, and then at least you can rule that out.

Seeing as you installed a new charge pipe and intercooler, double check all your fittings. Hopefully something as simple as that!

[minulache]

You can test very easily the vacuum line that goes from the boost solenoid to the WG and also from the valve cover to the boost solenoid. All ypu need is a small vacuum pump like this: https://www.amazon.com/HTOMT-Automot...s%2C205&sr=8-5

If it holds vacuum, the lines are ok. Next step would be the boost solenoid. Unfortunately, there is no proper way that I found to test it, so maybe just changing it would be the deal. But before that, I would do a boost leak test so you have all the leaks tested and leave the solenoid at last. The testings are easy to do and straight forward, in tops 1 hour you can diagnose

[wheela]

In addition to making sure the vacuum lines hold vacuum, also check that none are collapsing shut under vacuum. I've seen some people post that they had no leaks, but the short vac line between the valve cover and solenoid was collapsing shut under vacuum. If vacuum can pinch it shut, you may not get sufficient vac to the wastegate canister to pull the gate closed strongly enough to make proper boost.

[bL79]

Thanks everyone,

I replaced the vacuum lines from the boost solenoid since I could do that quickly.

Took the car around the block a bit and seems the issue persists. Though I'm confident the lines were tired, I could easily pinch them and I swear it feels more responsive down low. Data does seem to indicate the wg moves a bit better now and I actually peaked at 70% which is new.

Problem persists though. I'm just going to order another boost solenoid since it seems old. Also just wiggling the brake booster vacuum line fitting causes a leak so I'll be replacing that too. Lastly Ill readjust the FMIC air entry clamp. I thought I tightened it well but visually it looks a bit suspect. Unfortunately that's the one piece of plastic still in the intake chain I fussed with so I was hesitant to go crazy tight on the clamps.

Latest log
https://datazap.me/u/bl79/log-172740...-24&zoom=21-70

[minulache]

Maybe it would be a good idea to also try with some other OTS maps from MHD, just to rule that out?
If after the boost solenoid the problem persists, I would do a boost leak test just to pinpoint exactly where the problem might be from. It's better than to just throw parts at the problem, but have no idea what it could be....