[335_DE90]

My 2010 335d has been feeling sluggish/unresponsive. Its fully deleted has r90 hpfp, all new vacuum lines, pressure converters, solenoids etc. I logged my boost pressure in protools and it seems like it lags behind the commanded value by 5-7 sometimes 10 psi when I'm giving it throttle. It does eventually make it up to or less than the targeted value by 1-2psi, but it takes 2-4seconds. I'll also add that it acts like that intermittently. Sometimes it drives fine, sometimes it lags a little. Is my wastegate sticking? It has no vacuum leaks.

I can provide logs if needed.

Any advice is appreciated

[awenthol]

I assume that means you've reviewed exhaust pressure data?

[lnxguy]

I'd download TestO and use it for logging. You can basically log anything with that tool. Should give you a good idea as to what's going on.

[335_DE90]

When I logged with protools it looks like when its acting laggy it has lower manifold drive pressure, once it starts to build boost the manifold pressure increases.

[MidWillamette335d]

I think I have the same problem. At the bottom of my post are my logs in graphic form. You can see the boost "catching up". One thing that interests me is that the "actual" drops off very slowly as compared to the requested. Makes me think there is an issue with the actuator, though I hear the nature of building and bleeding vacuum for the crossover isn't as fast as some people's pedal input. Definitely run some logs and post them up I'd be curious to compare. Good luck figuring it out...

https://www.e90post.com/forums/showthread.php?t=1890079

[335_DE90]

Here is a log that I took, the second page has it graphed.

https://docs.google.com/spreadsheets...it?usp=sharing

These are some where I got on it pretty hard.
https://docs.google.com/spreadsheets...it?usp=sharing

https://docs.google.com/spreadsheets...it?usp=sharing

[lnxguy]

Vac pump leaking? I've got a similar issue with mine. Runs fine when cold, but once it heats up actual + requested lags behind quite a bit down low. The one thing I haven't looked at is the IAT sensor on the boost hose before the ASV/EGR/Intake. I've done vac lines, ISTA testing, etc the whole deal. I'll need to get an inspection camera and take a peak at the HP turboski next I guess.

[335_DE90]

I'm thinking it's either the vacuum canister controlling the wastegate or the wastegate itself is hanging up because even when I'm WOT its struggling to make the commanded 43psi it barely made it to 39-40psi. So I think the wastegate isn't closing properly.

[lnxguy]

Originally Posted by 335_DE90

I'm thinking it's either the vacuum canister controlling the wastegate or the wastegate itself is hanging up because even when I'm WOT its struggling to make the commanded 43psi it barely made it to 39-40psi. So I think the wastegate isn't closing properly.

You've checked the system for boost leaks?

[335_DE90]

Originally Posted by lnxguy

You've checked the system for boost leaks?

Yes, I have a Wagner Evo 3 intercooler with the atm turbo outlet and intake elbow, I have no leaks.

[maryjane]

You need a mityvac......you can check all these functions.
Hook it to the wastegate you can HEAR it shut upon release of vac....then leave it unplugged for a run.....then you'll know its not OPENING at all.
Also chech the front compressor bypass for full movement with the mityvac...It might not be closing fully or might not be holding vac.

[335_DE90]

Originally Posted by maryjane

You need a mityvac......you can check all these functions.
Hook it to the wastegate you can HEAR it shut upon release of vac....then leave it unplugged for a run.....then you'll know its not OPENING at all.
Also chech the front compressor bypass for full movement with the mityvac...It might not be closing fully or might not be holding vac.

You're saying to drive it with the wastegate unhooked so it makes full boost?

[maryjane]

Not for long.....just to keep it from getting STUCK open.....testing.
Just to make sure, the wastegate is UNDER the motor just inside the downpipe there should be a spliced vac line right at the side of the AC compressor.....not to be confused with the big plunger on the side( changeover )

[maryjane]

PM me for number to text if thats easier.

[335_DE90]

Originally Posted by maryjane

Not for long.....just to keep it from getting STUCK open.....testing.
Just to make sure, the wastegate is UNDER the motor just inside the downpipe there should be a spliced vac line right at the side of the AC compressor.....not to be confused with the big plunger on the side( changeover )

When I pull vacuum on the wastegate (yes the bottom one) it holds 28inmg no problem, but when I'm looking at it with a mirror it barely moves like barely a wiggle. And when I release the vacuum it barely moves back with no click sound like the valve shut.

[MidWillamette335d]

When I tested mine it hardly moved at all also, I'd say 4-5mm. When you release the vacuum are you bleeding it from the tool or pulling the line off the pump? When I did this, I pulled the line so it'd snap back for that audible sound, I think if bleeding off the pump, it'd be slower and might not be heard.

Also, just for talking purposes, do you think that a slightly open wastegate would contribute to the boost lag in the lower rpms? I can totally see not achieving max boost under that condition when the larger turbo is fully involved, but not sure it would affect the low end. My understanding is the larger turbo doesn't kick in until about 3k, which would be when the changeover actuator from small to large turbo opens fully and the exhaust gases flow freely over both turbines for max boost.

[maryjane]

The big turbo is never completely offline. Only the smaller turbo is ever bypassed. Wastegate actuators CAN get sticky/slow moving. Typically a laggy small turbo is because of bad pressure converters or filed or failing EV under the vac assembly OR mal adjusted changeover rod threads. When it all works its a great system......but when it starts acting up it can be a nightmare to solve the actual issues. TESTO if your best friend for logging and helping to diagnose issues.

[335_DE90]

Originally Posted by MidWillamette335d

When I tested mine it hardly moved at all also, I'd say 4-5mm. When you release the vacuum are you bleeding it from the tool or pulling the line off the pump? When I did this, I pulled the line so it'd snap back for that audible sound, I think if bleeding off the pump, it'd be slower and might not be heard.

Also, just for talking purposes, do you think that a slightly open wastegate would contribute to the boost lag in the lower rpms? I can totally see not achieving max boost under that condition when the larger turbo is fully involved, but not sure it would affect the low end. My understanding is the larger turbo doesn't kick in until about 3k, which would be when the changeover actuator from small to large turbo opens fully and the exhaust gases flow freely over both turbines for max boost.

Hard to say, mine barely moved at all if any when I tested it. As far as low end response I would think if any exhaust gas is going out the wastegate it is going to be lagging. I'm straight piped so when the car is lagging it drones really bad like its dumping through the wastegate, but when the car is acting responsive it just sounds like the turbo is spooling.

[awenthol]

I looked at logs--where is exhaust pressure data?

"Exhaust pressure" column is just a constant value. There's "drive pressure" but based on the values, that can't be mixed up with exhaust. You really need to compare exhaust pressure/boost, in this case.