[335NJ]

On cold starts, with the new firmware set to FUD-98, and even when it's not using the FUD settings (although not as bad), I have terrible rattle for about 15-20 seconds, then as it idles down, it goes away. Tapping the gas to high idle doesn't cause it to come back either when I'm just in neutral.

Would this be an indication of a vacuum leak? Maybe it rattles until vacuum has a chance to build up? I bought a vacuum gauge so I'll know soon enough if it's not holding vacuum, but thought I'd ask for some opinions.

[335NJ]

So I hooked a T into the right vacuum canister, brought the vacuum to "normal at idle" and shut the car off. After 10-15 minutes, the reading has dropped 1.5 in/hg. From 28in/hg to 26.5in/hg.

Indication of a vacuum leak it appears.

[Sgop335]

You were at 28 in of hg at idle and then 15 min? I can check mine. Its normal for it to drop tho.

[335NJ]

Originally Posted by Sgop335

You were at 28 in of hg at idle and then 15 min? I can check mine. Its normal for it to drop tho.

I hooked up the T like pictured below, started the car & let it idle until the vacuum gauge stopped moving (15 seconds?), then shut it down. It stopped at 28in/hg, then 15 minutes later (Car still off) it read 26.5in/hg. Only thing I should note is that when I popped the line off the top of the canister, I could hear hissing from the opposite side of the engine as well.

I thought idle vacuum at the canisters was supposed to be between 22-25in/hg?

[Sgop335]

You seem fine. 28 is great. Think it drops to 25 or so after a minute or more of idle. Mine pulls 25 at idle. They are supposed to be 22-25.and hissing sound is good.

Even after 15mins its 26.5? Wow

[335NJ]

Originally Posted by Sgop335

You seem fine. 28 is great. Think it drops to 25 or so after a minute or more of idle. Mine pulls 25 at idle. They are supposed to be 22-25.and hissing sound is good.

Even after 15mins its 26.5? Wow

LOL, so I came in expecting a vacuum leak, left pretty sure it's better than normal

Well, this is all coming up because of how bad my WG rattle is on startup for about 15-25 seconds. Which makes me think that once vacuum builds back up, the WG works normally, but until then, it has inconsistent vacuum.

Thanks for checking that for me by the way!

[Sgop335]

Well..your vacuum canisters are great. But how about the boost solenoids? That controls the wg.

[335NJ]

Originally Posted by Sgop335

Well..your vacuum canisters are great. But how about the boost solenoids? That controls the wg.

Those are next to be tested. I couldn't figure out how to T into each one, even by looking at Terry's video on N54Tech. I'll figure it out i'm sure, as I was trying to look into it on my phone versus a larger computer screen to actually see clearer.

I really hope they test bad honestly, because i'd gladly slap new ones in to resolve some of the goofy issues I have at low throttle and rattle at idle like stated above, and on acceleration.

Edit: I know how to do the solenoid test now. But it's dark outside so I'll test them suckers tomorrow!

[Sgop335]

Sounds good! Remove the hose between and check each one individually, while plugging the other.

[924er]

My car has a wg rattle upon start up the same way u described. I always thought it was normal

[335NJ]

Originally Posted by Sgop335

Sounds good! Remove the hose between and check each one individually, while plugging the other.

Thanks for the help!

I really hope they're bad, this might help explain the inconsistent boost at WOT, it'll fluctuate +/- 1-2psi, the rattle on acceleration, etc.

I bought all new Verocious Motorsports silicone vacuum line (13ft) to replace them all anyway, so hopefully this all gets sorted. The line I bought is rated for high temp too so it's a nice replacement for the old lines there now.

[Sgop335]

Originally Posted by 335NJ

Thanks for the help!

I really hope they're bad, this might help explain the inconsistent boost at WOT, it'll fluctuate +/- 1-2psi, the rattle on acceleration, etc.

I bought all new Verocious Motorsports silicone vacuum line (13ft) to replace them all anyway, so hopefully this all gets sorted. The line I bought is rated for high temp too so it's a nice replacement for the old lines there now.

You are welcome Sir! Glad to be of assistance. Yes silicone lines are one of the best things. I replaced my firewall solenoid last week.

[335NJ]

Originally Posted by Sgop335

You are welcome Sir! Glad to be of assistance. Yes silicone lines are one of the best things. I replaced my firewall solenoid last week.

Did you use BMW original? Or the other brand from ECS?

[Sgop335]

Originally Posted by 335NJ

Did you use BMW original? Or the other brand from ECS?

I got oem locally from getbmwparts. Its the same as Piersburg, which is cheaper and way to go.

[335NJ]

Ok so I tested the firewall side solenoid. With menu 10 set to 5000RPM (full vacuum) I get 24in/hg. It should be ~30in/hg I believe is that correct?

Actually it looks like I'm only about 2in/hg under the example in the video on N54Tech. Not sure that it's enough to be concerned about.

[Sgop335]

Originally Posted by 335NJ

Ok so I tested the firewall side solenoid. With menu 10 set to 5000RPM (full vacuum) I get 24in/hg. It should be ~30in/hg I believe is that correct?

Actually it looks like I'm only about 2in/hg under the example in the video on N54Tech. Not sure that it's enough to be concerned about.

I dont knoe menu 10

Take a look at this, if you havent and let me know. This is how i checked.

At idle, at 3k etc.

[335NJ]

Originally Posted by Sgop335

I dont knoe menu 10

Take a look at this, if you havent and let me know. This is how i checked.

At idle, at 3k etc.

http://www.n54tech.com/forums/showthread.php?t=13114

Video at the top, and yeah that's the chart I was basing my 30in/hg comment from.

[Sgop335]

Its cool you can adjust the sloenoid vacuum. Video shows 25 or so max, so seems you are ok. How about the other one?

Mine are about 17, stock (also seen in the document). Firewall was pulling 5in less so replaced it.

30 is not at the solenoid.

[335NJ]

Originally Posted by Sgop335

Its cool you can adjust the sloenoid vacuum. Video shows 25 or so max, so seems you are ok. How about the other one?

Mine are about 17, stock (also seen in the document). Firewall was pulling 5in less so replaced it.

30 is not at the solenoid.

I believe the way the video shows you how to do it, means it's testing vacuum to both wastegate actuators, so I'm not sure I'd have to perform the same thing on the other one? I guess I can for the heck of it, but I'll upload a picture of my connection so you have a better idea what I'm saying.

Thanks again! I'm going to replace all of the vacuum lines this weekend if I don't get time this week, but figured I'd try to get a good baseline.

[Sgop335]

Originally Posted by 335NJ

I believe the way the video shows you how to do it, means it's testing vacuum to both wastegate actuators, so I'm not sure I'd have to perform the same thing on the other one? I guess I can for the heck of it, but I'll upload a picture of my connection so you have a better idea what I'm saying.

Thanks again! I'm going to replace all of the vacuum lines this weekend if I don't get time this week, but figured I'd try to get a good baseline.

I disconnected the hose between the two and checked individually as shown in the doc. Just plug each one when you check.