E92 335D Drive / Boost Issues

HughiusMaximus · 04-01-2015, 07:47 AM

Hi Guys,

Advice needed please - my mapped 335d has recently developed a problem which is more evident in the higher gears.

Car takes off fine in 1st, but when pressing the accelerator from 3rd gear and up there is a significant flat spot lower on the power band, and what feels like back pressure on the pedal making it harder to press.

I know the obvious answers are 1, a faulty small turbo actuator, or 2, turbo vacuum hose issues.

But the fact that the car takes off fine makes me think an actuator issue is unlikely, as I have had that in the past and it was evident in first at take off as well.
Also I have taken the car to a local garage with full diagnostic kit, and there are no error codes showing.
If there were vacuum hose leaks it would be showing an boost pressure error code apparently....

They guy in the garage suggested checking for gearbox software updates to see if that sorts it, but I find that unlikely.

I'm wondering if its DPF related - car has done around 117k miles, so its in that window where the DPF can give trouble. But I would have thought that if it was DPF related there would be error codes showing.

Maybe its just in my head, but the fact that the accelerator feels harder to push when the issue is evident is also a strange one.

Any advice or words of welcome!

Thanks!

AdzC · 04-01-2015, 07:58 AM

I had an issue recently. The vacuum pipes were replaced as they were perished but this problem occurred afterwards.

I had a DPF light come on my dash. It turned out to be my exhaust pressure sensor which needed replacing.

Hope you get it sorted.

HughiusMaximus · 04-01-2015, 08:19 AM

I'm pretty sure the exhaust pressure sensor was replaced a few months back as well!

Its a strange one, my gut tells me its DPF / Exhaust system related, but the lack of any error codes isn't helping!

To be fair to the guy in the garage, he said it would be easy to start throwing parts at it, but that might not solve anything....

04-02-2015, 04:36 AM

sounds like it's not getting enough of air. so the MAF sensor might be the one faulty.
i am dealing with the opposite, no pressure at low revs, but it is not performing at higher revs either as it once had, but more evident at low revs....also the MAP sensor

Yozh · 04-03-2015, 01:08 AM

Ah, as always with these issues, it would be good to see what codes have popped-up and what parameters do say.

HughiusMaximus · 04-03-2015, 05:38 AM

Quote:

Originally Posted by Yozh

Ah, as always with these issues, it would be good to see what codes have popped-up and what parameters do say.

That's the strange thing... I brought it to a garage I use a lot and it isn't showing any error codes...

Everything is reading as normal.

kiel_dafo_kenyg_as · 04-03-2015, 06:21 AM

Quote:

Originally Posted by HughiusMaximus

Maybe its just in my head, but the fact that the accelerator feels harder to push when the issue is evident is also a strange one.

Dirt built up behind the pedal?
A faulty / cracked accelerator pedal potentiometer?
http://de.bmwfans.info/parts-catalog..._pedal_module/

From your description it's a mechanical issue, therefore I have not much hope it will be of help but you could try resetting the pot:

Keep foot away from brake pedal during whole process! You don't want to start the engine.

-turn ignition on
-wait 3-5 sec
-push pedal all the way down to activate kickdown switch
-hold for 3-5 sec
-release pedal
-wait 3-5 sec
-push pedal all the way down to activate kickdown switch
-hold for 3-5 sec
-release pedal and turn ignition off
-wait 20 sec
---test drive

HughiusMaximus · 04-03-2015, 07:38 AM

Thanks, I'm actually away till Monday but I'll try it when I'm home...

I'm always amazed by how many unknown resets there are!

Mik325tds · 04-03-2015, 10:22 AM

If you feel unusual restriction in the gas pedal, you should be able to feel it without the engine running also - otherwise your but dyno is playing tricks on you.
I'd advise to buy a $30 cable and get Test-o (free-ware with donations possible), (see this post http://www.e90post.com/forums/showthread.php?t=1079838) to analyse how well your actual boost tracks the requested boost. You'll be able to read pretty much all sensors that the DDE has available and that will help you figure out the problem. There are a few well known guys around here that I'm sure will help you out once you post some logs.

04-01-2015, 07:47 AM	#1
HughiusMaximus Private 7 Rep 56 Posts Drives: E92 335d SE Coupe Join Date: Sep 2012 Location: Bristol iTrader: (0)	E92 335D Drive / Boost Issues Hi Guys, Advice needed please - my mapped 335d has recently developed a problem which is more evident in the higher gears. Car takes off fine in 1st, but when pressing the accelerator from 3rd gear and up there is a significant flat spot lower on the power band, and what feels like back pressure on the pedal making it harder to press. I know the obvious answers are 1, a faulty small turbo actuator, or 2, turbo vacuum hose issues. But the fact that the car takes off fine makes me think an actuator issue is unlikely, as I have had that in the past and it was evident in first at take off as well. Also I have taken the car to a local garage with full diagnostic kit, and there are no error codes showing. If there were vacuum hose leaks it would be showing an boost pressure error code apparently.... They guy in the garage suggested checking for gearbox software updates to see if that sorts it, but I find that unlikely. I'm wondering if its DPF related - car has done around 117k miles, so its in that window where the DPF can give trouble. But I would have thought that if it was DPF related there would be error codes showing. Maybe its just in my head, but the fact that the accelerator feels harder to push when the issue is evident is also a strange one. Any advice or words of welcome! Thanks!
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04-01-2015, 07:58 AM	#2
AdzC Private First Class 13 Rep 152 Posts Drives: E92 335d Join Date: Jul 2012 Location: Lancashire iTrader: (1)	I had an issue recently. The vacuum pipes were replaced as they were perished but this problem occurred afterwards. I had a DPF light come on my dash. It turned out to be my exhaust pressure sensor which needed replacing. Hope you get it sorted. __________________ Space Grey E92 335d 1998 Yamaha R1
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04-01-2015, 08:19 AM	#3
HughiusMaximus Private 7 Rep 56 Posts Drives: E92 335d SE Coupe Join Date: Sep 2012 Location: Bristol iTrader: (0)	I'm pretty sure the exhaust pressure sensor was replaced a few months back as well! Its a strange one, my gut tells me its DPF / Exhaust system related, but the lack of any error codes isn't helping! To be fair to the guy in the garage, he said it would be easy to start throwing parts at it, but that might not solve anything....
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04-02-2015, 04:36 AM	#4
Martin80k Guest 0 Rep n/a Posts Drives:	sounds like it's not getting enough of air. so the MAF sensor might be the one faulty. i am dealing with the opposite, no pressure at low revs, but it is not performing at higher revs either as it once had, but more evident at low revs....also the MAP sensor
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04-03-2015, 01:08 AM	#5
Yozh Colonel 871 Rep 2,611 Posts Drives: 2011 335d M-Sport Join Date: Mar 2014 Location: Wet Coast iTrader: (4)	Ah, as always with these issues, it would be good to see what codes have popped-up and what parameters do say.
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04-03-2015, 07:38 AM	#8
HughiusMaximus Private 7 Rep 56 Posts Drives: E92 335d SE Coupe Join Date: Sep 2012 Location: Bristol iTrader: (0)	Thanks, I'm actually away till Monday but I'll try it when I'm home... I'm always amazed by how many unknown resets there are!
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04-03-2015, 10:22 AM	#9
Mik325tds Major 808 Rep 1,192 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	If you feel unusual restriction in the gas pedal, you should be able to feel it without the engine running also - otherwise your but dyno is playing tricks on you. I'd advise to buy a $30 cable and get Test-o (free-ware with donations possible), (see this post http://www.e90post.com/forums/showthread.php?t=1079838) to analyse how well your actual boost tracks the requested boost. You'll be able to read pretty much all sensors that the DDE has available and that will help you figure out the problem. There are a few well known guys around here that I'm sure will help you out once you post some logs.
	Appreciate 0 Quote