[jogill]

My car seems to be boosting way too high on MHD map 0 or map 1.

2011 335Xi MT (N55) with 115,000km (72,000 miles) running MHD stage 1, car is completely stock with a VRSF charge pipe. I just changed the coils (Eldor) and plugs (Bosch ZR5TPP33S).

After mapping stage 1 and driving around watching the gauges I noticed the boost and target were not matching so I did a 3rd gear pull 2500 to 5000rpm. Boost is slow to rise and then goes way over. I don’t get any error msg or DME codes. Log is here https://datazap.me/u/jgill/mhd-map-1?log=0&data=4-15

So then I changed the map to stock map 0, and it appears to be doing the same, hitting 22PSI. Log is here https://datazap.me/u/jgill/stock-map?log=0&data=4-5-15

Seems like the boost climbs with RPM. I'm guessing not a vaccum leak since the boost is going too high?
I’m new to this, so any insight would be greatly appreciated. Anyone seen this before?

Thanks,

John

[wheela]

Hey, I seem to recall reading about a member that had a similar problem in the n55 e-series MHD thread. Their issue turned out to be the small vacuum line between the boost solenoid and wastegate was collapsing under vacuum, so waste gate was slow to close (slow building boost), then vacuum lock shut and overboost. They replaced the tube with a fresh silicone tube and the issue went away. Not sure is that's your issue, but it's such a simple thing it would be worth looking if you haven't yet.

[anjuna]

What you are seeing is the boost in the charge pipe. You should be monitoring 'boost PSI (MANI)' to see the true boost your engine is receiving. NOTE that your 'throttle position' drops from 100% to ~28% once the "overboost" condition is met.


It looks like your 'load req' and 'load actual' are spot on, and you are not experiencing heavy timing pulls (!NOT! corrections) due to this "overboost" - You will see heavily negative timing without correction. This is "engine protection" mode.

[TheGoodTheBadTheUgly]

Originally Posted by anjuna

What you are seeing is the boost in the charge pipe. You should be monitoring 'boost PSI (MANI)' to see the true boost your engine is receiving. NOTE that your 'throttle position' drops from 100% to ~28% once the "overboost" condition is met.


It looks like your 'load req' and 'load actual' are spot on, and you are not experiencing heavy timing pulls (!NOT! corrections) due to this "overboost" - You will see heavily negative timing without correction. This is "engine protection" mode.

How do we get that damn option ti log the manifold TMAP sensor. I don't have this with my MHD logger and it would really help me.

[anjuna]

Originally Posted by TheGoodTheBadTheUgly

How do we get that damn option ti log the manifold TMAP sensor. I don't have this with my MHD logger and it would really help me.

get the MHD logger

In all seriousness, at first I was not-so-sold on the logger ability. Kinda seemed like unnecessary licensing fluff. Their latest revision added quite a few additional cool DAQ points.

So, I would say it was not worth it before, but seems to be getting better and is at a point that it IS worth it now.

edit - it's kind of worthless IMO with the KDCAN cable. You really need the wifi adapter (it's about 5-10x the speed for DAQ) to make real value out of it.

edit while editing - I am NOT a MHD shill. I am the furthest from it. However, the tools they provide are good.... Just not the maps. God no to the maps.

[wheela]

My MHD logger (e-chassis n55 ver. 2.2) doesn't have "boost PSI (MANI)"? But even logging charge pipe pressure, his boost curve still shouldn't look that that. I ran that same map for a while, and mine approached target relatively quickly, and held about 1 - 1.5 psi below target through the pull. To add onto your comment about the maps, I'm currently on their 1+ 93 oct map, and my car is literally no faster 0-60 than stock???

[anjuna]

Originally Posted by wheela

My MHD logger (e-chassis n55 ver. 2.2) doesn't have "boost PSI (MANI)"? But even logging charge pipe pressure, his boost curve still shouldn't look that that. I ran that same map for a while, and mine approached target relatively quickly, and held about 1 - 1.5 psi below target through the pull. To add onto your comment about the maps, I'm currently on their 1+ 93 oct map, and my car is literally no faster 0-60 than stock???

I am "early F series" which means a Frankenstein between late E and early F. I actually have more E series components than F.......

I am surprised to see no 'boost mani ram psi' exists in your version of MHD.

I agree that his boost curve shouldn't look like that, but its a cascading effect.

1. Car underboosts - more WGDC
2. Car hits target boost - ok....
3. Car overboosts - cut throttle plate, try to decrease WGDC
4. DME hits PID floor max - can't cut WGDC any further
5. Closed throttle plate means more restriction to mani.
6. More restriction to mani with same "flow" means more "boost"
7. "Boost" increases due to restriction.
rinse, cycle, repeat.

We don't know if he is EWG or PWG yet (or I am dumb, v possible) but PWG would have to "fight" the actual wastegate actuator to keep it closed. The vacuum pulls it closed, and the same amount of vacuum against 12psi cannot keep it closed at 20psi, so I doubt this is a line issue.

Maybe solenoid? Maybe tune?

I'd flash back to stock and datalog. If there is massive boost creep there, mechanical. If not, tune.

[TheGoodTheBadTheUgly]

Originally Posted by anjuna

get the MHD logger

In all seriousness, at first I was not-so-sold on the logger ability. Kinda seemed like unnecessary licensing fluff. Their latest revision added quite a few additional cool DAQ points.

So, I would say it was not worth it before, but seems to be getting better and is at a point that it IS worth it now.

edit - it's kind of worthless IMO with the KDCAN cable. You really need the wifi adapter (it's about 5-10x the speed for DAQ) to make real value out of it.

edit while editing - I am NOT a MHD shill. I am the furthest from it. However, the tools they provide are good.... Just not the maps. God no to the maps.

Yeah in my post I said that my MHD logger didn`t have this option, not that I don`t have the MHD logger . Totally agree that is pretty necessary to have MHD logging tools!

[jogill]

I did try it on Map 0 but it did the same thing, that was the second log. I emailed MHD and Justin said it is a hardware issue, which is what I suspected. I tried to move the actuator by hand, but I couldn’t which made me worried. I put my vacuum pump on the line to the actuator but I couldn’t get it to move so I tried a few more times and then it came free. It appeared to be stuck closed. Now it seems to function properly, opening and closed smoothly without sticking.

I then took the solenoid off and it seems to function as it should when I test it with vacuum and power, however I suspect its is the culprit and was applying full vacuum for a long period of time and somehow the jammed the actuator or the waste gate closed and therefore the car couldn’t control the boost. On the graph the boost rises with RPM so that would indicate to me that the waste gate is in a fixed position, however I’m no expert. I’m not sure how the waste gate would get jammed shut so I hope its not the actuator going bad since apparently you cant buy just the actuator.

I’ve ordered a new solenoid (BMW part# 11747626351 or Pierburg part# 7.00887.21.0) so hopefully that resolves the issue. If not I’ll replace the vacuum line from the solenoid to the actuator.

Once the new solenoid is on I’ll update with the result. I would like to try it again with the old solenoid but I don’t have time.

Originally Posted by anjuna

What you are seeing is the boost in the charge pipe. You should be monitoring 'boost PSI (MANI)' to see the true boost your engine is receiving. NOTE that your 'throttle position' drops from 100% to ~28% once the "overboost" condition is met.


It looks like your 'load req' and 'load actual' are spot on, and you are not experiencing heavy timing pulls (!NOT! corrections) due to this "overboost" - You will see heavily negative timing without correction. This is "engine protection" mode.

I don’t have ‘boost PSI (MANI)’ as an option

EDIT: updated with correct part numbers

[anjuna]

Originally Posted by jogill

I did try it on Map 0 but it did the same thing, that was the second log. I emailed MHD and Justin said it is a hardware issue, which is what I suspected. I tried to move the actuator by hand, but I couldn’t which made me worried. I put my vacuum pump on the line to the actuator but I couldn’t get it to move so I tried a few more times and then it came free. It appeared to be stuck closed. Now it seems to function properly, opening and closed smoothly without sticking.

I then took the solenoid off and it seems to function as it should when I test it with vacuum and power, however I suspect its is the culprit and was applying full vacuum for a long period of time and somehow the jammed the actuator or the waste gate closed and therefore the car couldn’t control the boost. On the graph the boost rises with RPM so that would indicate to me that the waste gate is in a fixed position, however I’m no expert. I’m not sure how the waste gate would get jammed shut so I hope its not the actuator going bad since apparently you cant buy just the actuator.

I’ve ordered a new solenoid (BMW part# 11747649407 or Pierburg part# 7.00887.22.0) so hopefully that resolves the issue. If not I’ll replace the vacuum line from the solenoid to the actuator.

Once the new solenoid is on I’ll update with the result. I would like to try it again with the old solenoid but I don’t have time.



I don’t have ‘boost PSI (MANI)’ as an option

Good to know!! That's the first I have heard of an issue with the actuator. I am not sure which portion was seized and/or dragging, but there are plenty of ultra high temperature anti-sneeze products out there (like permatex copper) and those have worked wonders for me in many many many applications.

Also, I apologize about the lack of boost ram mani option.... Like I said, I'm halfway E-series and halfway F-series, but e90post is the most applicable place for me to talk about tuning/etc. so it helps me to understand what options are available and what aren't.

If you would be so kind as to make sure your MHD app is up-to-date, and possibly post screen captures here of all the possible data points??

Originally Posted by TheGoodTheBadTheUgly

Yeah in my post I said that my MHD logger didn`t have this option, not that I don`t have the MHD logger . Totally agree that is pretty necessary to have MHD logging tools!

You too, if you want to help.

[wheela]

Here are the options I have available.

[wheela]

App version: N55e v2.20

[TheGoodTheBadTheUgly]

MHD N55e V2.20 Beta Tester

[wheela]

V2.20 beta, is that from before they went to v2.20, or are those beta changes TO v2.20 that are in beta testing right now?

[TheGoodTheBadTheUgly]

Originally Posted by wheela

V2.20 beta, is that from before they went to v2.20, or are those beta changes TO v2.20 that are in beta testing right now?

I've had Beta Tester for a long time now, but it is when you have some options that they haven't officialy released yet. Like back then, before they added burble control, if you were a Beta Tester you could have acces to the options.

[anjuna]

Originally Posted by TheGoodTheBadTheUgly

I've had Beta Tester for a long time now, but it is when you have some options that they haven't officialy released yet. Like back then, before they added burble control, if you were a Beta Tester you could have acces to the options.

Interedesting.

Also, I noticed that you have ALL of those selected. Are you actually able to log all those data points!!??

I am NOT a beta tester, just using the latest APK for android. However, if I try to select “too many” points for logging, I get a “failed to contact DME” message. Unfortunately it’s kind of a balancing act, especially as they have opened up a metric fuck ton of CANbus modules, ethanol sensors, and the likes for my DME.

[TheGoodTheBadTheUgly]

Originally Posted by anjuna

Interedesting.

Also, I noticed that you have ALL of those selected. Are you actually able to log all those data points!!??

I am NOT a beta tester, just using the latest APK for android. However, if I try to select "too many" points for logging, I get a "failed to contact DME" message. Unfortunately it's kind of a balancing act, especially as they have opened up a metric fuck ton of CANbus modules, ethanol sensors, and the likes for my DME.

I think I can actually log all of these at the same time. I never got that error for having all the parameters selected!

Here is a log for example. I quickly counted and their seems to be all the parameters!

https://datazap.me/u/thegoodthebadth...og=0&data=4-21

[wheela]

I don't have as many options available as you, but I haven't run into any issues either from having too many parameters checked (i'm using the orange MHD wifi adapter).

[jogill]

I replaced the solenoid and it did not fix the problem

The only other thing I can think it could be would be the actual wastegate actuator itself, maybe it's sticking and not releasing when commanded. I don't feel confident in this diagnosis since the exhaust pressure is pushing against it so for it to stick and overcome that pressure would be pretty significant. Although I don't know what else it could be.

On the N54 you can buy replacement actuators however on the N55 it's considered part of the turbo so you can't just buy the actuator, at least I'm not finding it. Anyone replace an actuator on a N55?

Many people seem to replace the vacuum lines however I don't see how that would contribute to overboost since the system requires vacuum to make boost. Although I'll likely just replace the line from the solenoid to the actuator if I'm going to replace the actuator anyway.

Anyone have any ideas?

[wheela]

Originally Posted by jogill

I replaced the solenoid and it did not fix the problem

The only other thing I can think it could be would be the actual wastegate actuator itself, maybe it's sticking and not releasing when commanded. I don't feel confident in this diagnosis since the exhaust pressure is pushing against it so for it to stick and overcome that pressure would be pretty significant. Although I don't know what else it could be.

On the N54 you can buy replacement actuators however on the N55 it's considered part of the turbo so you can't just buy the actuator, at least I'm not finding it. Anyone replace an actuator on a N55?

Many people seem to replace the vacuum lines however I don't see how that would contribute to overboost since the system requires vacuum to make boost. Although I'll likely just replace the line from the solenoid to the actuator if I'm going to replace the actuator anyway.

Anyone have any ideas?

I think the idea with the vacuum line is that it collapses under vacuum, so its slow to apply vacuum to the actuator, therefore slow to build boost. So the DME keeps seeing a big delta between the boost target and actual boost, so it keeps applying duty cycle to the boost solenoid. By the time enough vacuum seeps through the collapsed line to hit boost, the boost solenoid may reduce the duty cycle, but now you have the actuator cylinder full of vacuum, and it can only release back through the collapsed vacuum line. But since that same vacuum is holding the line collapsed shut, the actuator cylinder takes a long time to loose its vacuum - which holds your wastegate closed longer than intended, causing the overboost condition. Despite the boost being painfully slow to build up in the first place.

[jogill]

Originally Posted by wheela

I think the idea with the vacuum line is that it collapses under vacuum, so its slow to apply vacuum to the actuator, therefore slow to build boost. So the DME keeps seeing a big delta between the boost target and actual boost, so it keeps applying duty cycle to the boost solenoid. By the time enough vacuum seeps through the collapsed line to hit boost, the boost solenoid may reduce the duty cycle, but now you have the actuator cylinder full of vacuum, and it can only release back through the collapsed vacuum line. But since that same vacuum is holding the line collapsed shut, the actuator cylinder takes a long time to loose its vacuum - which holds your wastegate closed longer than intended, causing the overboost condition. Despite the boost being painfully slow to build up in the first place.

Seems like I will replace that line to rule out that issue then. Anyone know how long of a piece is needed to go from the solenoid to the actuator? What what size is that line?

I went out to troubleshoot some more today and I found the wastegate actuator stuck, in the closed position I assume based on the high boost numbers. I could not get it free whatsoever. I even tried removing the nuts that secure it to the wastegate lever but even with some liquid wrench I couldn't get them loose. I just wanted to confirm its the actual actuator that is stuck and not the wastegate. This happened to me a few weeks ago when I was doing some troubleshooting but it came free and would open and close when I applied vacuum which is why I thought it was the solenoid causing the problem.

So now I'll replace that actuator and the vacuum line, which will have to be done at a shop. Thinking maybe I'll put on the VRSF catted DP while they are in there since its the same area and I would guess they'll need to remove the DP to gain access.

[ky0u]

Originally Posted by jogill

Seems like I will replace that line to rule out that issue then. Anyone know how long of a piece is needed to go from the solenoid to the actuator? What what size is that line?

3.5mm inner diameter. get like 3ft. It's excess but vac hose is cheap and it's always better to have too much. Not to mention having spare vac hose on hand is never a bad thing with these cars