[BMWerkeUSA]

Hello,

We checked the vacuum in my X5 this afternoon. The blue connection (on top of the EGR cooler) had over 25 inHg vacuum but the red connection (going to the compressor bypass valve vacuum actuator) had no vacuum. Is that normal? We checked it while the car was idling as well as after giving some gas up to 3500rmp.



Thanks

[Yozh]

Yes it is normal. The red connector you circled is an output of a compressor bypass feed so at idle it is closed and only activated at higher boost and after 2800 rpm for the X5 and 3200rpm for the 335d. No it will not activate if you rev your motor stationary.

[BMWerkeUSA]

Originally Posted by Yozh

Yes it is normal. The red connector you circled is an output of a compressor bypass feed so at idle it is closed and only activated at higher boost and after 2800 rpm for the X5 and 3200rpm for the 335d. No it will not activate if you rev your motor stationary.

Thanks Yozh!

[SouthDiesel190]

Originally Posted by BMWerkeUSA

Thanks Yozh!

I only know Yozh through reading this forum but he is the freaking man

[BMWerkeUSA]

All,

I cannot seem to find any vacuum leak or boost leak. I did run a test in ISTA to look at charge pressure versus exhaust pressure and here is what the output looks like. Is this normal?




Thanks

BTW: I just went for a drive and monitored the "Boost-pressure controller, activation", During idle and normal drive, it is about 94.98% but when I floor it, it goes as low as 9.9%. Is this normal?

[Yozh]

Normal. What you had monitored is a turbo switchover Duty ratio. 95% is pressure converter fully energized and turbo switchover closed with all exhaust directed towards the small turbo. 10% turbo switchover opened and all all exhaust goes to the large turbo. Your compressor bypass opens at this time as well.

[Yozh]

OPyiu need to give us a bit more info here. You mention about vacuum leaks. But we don’t know anything about the a vehicle, issues, codes etc

[BMWerkeUSA]

Hello Yozh,

Here are the details:
2009 X5 35D with 98,500 miles.
I have the DUDMD Stage 1 tune with SCR off with 100% stock hardware.

The issue: I was getting half engine sign under heavy acceleration. Sometimes half engine sign accompanied by a check engine sign sometimes it was just a half engine sign that would go away once I stop and restarted the engine.


The main code I was getting is as follows:
00429A: Boost pressure control low pressure stage deviation.


I think that I may have just found the issue. I had decided to clean the MAF sensor with a Mass Air Flow Sensor cleaner from Autozone. Visually, the sensor looked clean but once I started spraying from both directions, I could see droplets of oil stay on the sensor once the MAF cleaner had evaporated. In any case, I sprayed it several times and let it dry for an hour. Then, I took the car for a test drive and floored it no less than half a dozen times both on D and DS mode. So far, it did not go into the limp mode and it seems that the idle has gotten smother. Time will tell if it is really fixed.

Thanks

[robnitro]

Also clean out your map sensor, they get sooted up and can cause boost issues. It's cheap, easy, preventative maintenance like you did with the maf

[BMWerkeUSA]

Originally Posted by robnitro

Also clean out your map sensor, they get sooted up and can cause boost issues. It's cheap, easy, preventative maintenance like you did with the maf

Yes, I can try but what cleaner should I use? Can I use the MAF cleaner?

[robnitro]

Yes it's plastics safe, just be careful to not poke in the hole hard.

[BMWerkeUSA]

Originally Posted by robnitro

Yes it's plastics safe, just be careful to not poke in the hole hard.

I took out the MAP sensor and the opening diameter was about half of what it should have been due to carbon build-up. I sprayed it with the MAF cleaner. Much of the CBU is removed but there is still some around the perimeter of the opening. I took the car for a test drive and pushed it hard a few times and fortunately there was no half engine sign or a check engine sign. I am more hopeful now that the issue is addressed.

Thanks for all you guys' help!

[madbim]

This is interesting, I have almost the same exact setup and same code that has been plaguing me.

2013 35D, 100k, DUDMD Stage 1, SCR off 100% stock hardware. Code appears under heavy throttle.

I have cleaned the MAF (maybe not through enough?), new seals for the boost hose are on my bench. MAP was replaced 30k ish miles ago.

Originally Posted by BMWerkeUSA

Hello Yozh,

Here are the details:
2009 X5 35D with 98,500 miles.
I have the DUDMD Stage 1 tune with SCR off with 100% stock hardware.

The issue: I was getting half engine sign under heavy acceleration. Sometimes half engine sign accompanied by a check engine sign sometimes it was just a half engine sign that would go away once I stop and restarted the engine.


The main code I was getting is as follows:
00429A: Boost pressure control low pressure stage deviation.


I think that I may have just found the issue. I had decided to clean the MAF sensor with a Mass Air Flow Sensor cleaner from Autozone. Visually, the sensor looked clean but once I started spraying from both directions, I could see droplets of oil stay on the sensor once the MAF cleaner had evaporated. In any case, I sprayed it several times and let it dry for an hour. Then, I took the car for a test drive and floored it no less than half a dozen times both on D and DS mode. So far, it did not go into the limp mode and it seems that the idle has gotten smother. Time will tell if it is really fixed.

Thanks

[BMWerkeUSA]

Originally Posted by madbim

This is interesting, I have almost the same exact setup and same code that has been plaguing me.

2013 35D, 100k, DUDMD Stage 1, SCR off 100% stock hardware. Code appears under heavy throttle.

I have cleaned the MAF (maybe not through enough?), new seals for the boost hose are on my bench. MAP was replaced 30k ish miles ago.

I did not mention here but we had replaced those seals a few months ago. The seal/O-ring between the "pink" hose (passenger side for me) and the inter-cooler was torn due to loose connection.

Cleaning the MAF took almost 75% of a spray can for me. I did several iterations to make sure that it is very clean. You might want to reset the adaptations for MAF after you clean it if you haven't already done so.

Good luck!

[BMWerkeUSA]

Originally Posted by BMWerkeUSA

Hello Yozh,

Here are the details:
2009 X5 35D with 98,500 miles.
I have the DUDMD Stage 1 tune with SCR off with 100% stock hardware.

The issue: I was getting half engine sign under heavy acceleration. Sometimes half engine sign accompanied by a check engine sign sometimes it was just a half engine sign that would go away once I stop and restarted the engine.


The main code I was getting is as follows:
00429A: Boost pressure control low pressure stage deviation.


I think that I may have just found the issue. I had decided to clean the MAF sensor with a Mass Air Flow Sensor cleaner from Autozone. Visually, the sensor looked clean but once I started spraying from both directions, I could see droplets of oil stay on the sensor once the MAF cleaner had evaporated. In any case, I sprayed it several times and let it dry for an hour. Then, I took the car for a test drive and floored it no less than half a dozen times both on D and DS mode. So far, it did not go into the limp mode and it seems that the idle has gotten smother. Time will tell if it is really fixed.

Thanks

Update: It has been six days since I cleaned the MAF and five days since I cleaned t he MAP sensor. I haven't gotten any Half Engine Sign even though I have been pushing the car somewhat.

[madbim]

I'm still working through my issue. Haven't yet had time to replace the seals in the boost hose. It definitely feels like it's down on power though when trying to get through the gears.

[BMWerkeUSA]

Originally Posted by madbim

I'm still working through my issue. Haven't yet had time to replace the seals in the boost hose. It definitely feels like it's down on power though when trying to get through the gears.

Since last update, I did get half engine signs a few times. I think that cleaning the MAF did help but did not restore the sensor completely. My next step is to replace the MAF ($106.86 at FCPEuro). I will post another update once I get around to doing it.

[madbim]

Originally Posted by BMWerkeUSA

Since last update, I did get half engine signs a few times. I think that cleaning the MAF did help but did not restore the sensor completely. My next step is to replace the MAF ($106.86 at FCPEuro). I will post another update once I get around to doing it.

Any update here? I've been down a long road, MAF may be next on my list.

[BMWerkeUSA]

Originally Posted by madbim

Any update here? I've been down a long road, MAF may be next on my list.

Update 2: I finally replaced the MAF. I feel like there is an improvement in the way that the car pulls but I did not push the car too hard yet. It seems to me that car is adapting to the new MAF at least as far as I can tell. The hesitation going from the 1st to 2nd gear at near full throttle seemed to have gone away.

[BMWerkeUSA]

Originally Posted by BMWerkeUSA

Update 2: I finally replaced the MAF. I feel like there is an improvement in the way that the car pulls but I did not push the car too hard yet. It seems to me that car is adapting to the new MAF at least as far as I can tell. The hesitation going from the 1st to 2nd gear at near full throttle seemed to have gone away.

Update 3: Spoke too early. The frequency of occurrence of Half Engine Sign went down but did not go away completely. Within the last eight days, the car went into limp mode twice. I don't seem to have any vacuum or boost leaks. I am wondering if this has anything to do with the tune I have.

[madbim]

Originally Posted by BMWerkeUSA

Update 3: Spoke too early. The frequency of occurrence of Half Engine Sign went down but did not go away completely. Within the last eight days, the car went into limp mode twice. I don't seem to have any vacuum or boost leaks. I am wondering if this has anything to do with the tune I have.

Thanks for the update. Still working on mine as well.