Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 10-01-2011, 11:00 PM
teklord69 teklord69 is offline
Officially Welcomed to the 'Fest
Location: Irvine, CA
 
Join Date: Apr 2010
Posts: 755
Mein Auto: 1993 BMW 318i
DISA Autopsy

I got bored and opened up the DISA. It was pretty hard to pry apart but I wanted to see the internals of this overpriced piece of plastic.

The rod is actuated by vacuum to move the yellow plastic up and down. At 100K miles, the rod as well as the metal clip that holds it to the yellow piece looked good, nothing was cracking or brittle from what I can see.


The vacuum is done by this spring and rubber (silicone?) plunger. The spring looked good as well as the rubber part. It was still flexible and seemed air tight.





The design flaw is here. This is where the DISA flap is connected to. After thousands of movement opening the flap on and off, it stresses this part and will eventually break.
This and the seal of the DISA valve to the intake manifold are the weak links.
Attached Thumbnails
Click image for larger version

Name:	IMG00332-20110930-1656.jpg
Views:	2039
Size:	211.2 KB
ID:	295549   Click image for larger version

Name:	IMG00333-20110930-1657.jpg
Views:	1827
Size:	204.6 KB
ID:	295550   Click image for larger version

Name:	IMG00334-20110930-1657.jpg
Views:	1842
Size:	162.7 KB
ID:	295551   Click image for larger version

Name:	IMG00336-20110930-1700.jpg
Views:	2192
Size:	149.3 KB
ID:	295552  
__________________
2003 E39 530iA Titanium Silver w/ Sport Package
Reply With Quote
Advertisement
  #2  
Old 10-02-2011, 05:23 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,248
Mein Auto: 02 BMW 525i M54 auto 130K
Thank you for taking the time and energy to autopsy your DISA (for the team)!

A few questions come to mind as I look at the nice photos:

Q1: Where does the DISA get its vacuum (there is no vacuum hose connection, for example so, does it 'make' its own vacuum)?
Q2: What happens when you put 12 volts DC to your DISA valve (presumably it will generate the vacuum to open the valve)?
Q3: Both Doru & Bazza-Aus noted the new DISA o-ring is 'ribbed and glued' while the old DISA o-ring is flattened; did you see the same phenomenon with your old & new DISA?

BTW, would you kindly compare the before-and-after closeups of the rectangular-cross-section o-ring side by side?

Here's what seems to be the case based on old/new DISA pictures from Bazza-Aus in this post:
- E39 (1997 - 2003) > DISA 0 Ring
Quote:
Originally Posted by Bazza-Aus View Post
The sealing is done via a built-in "lip" on the base of the unit that mimics an o-ring.



BTW, we need a better non-destructive TEST procedure!
- How to test DISA operation on the BMW E39

And, for the record, here's another DISA autopsy:
- E39 (1997 - 2003) > Press Gas, hesitation, stall...

Quote:
Wear melt on corner.


Crack on pivot.


Distortion when open.


Notice the ribbed new DISA o-ring:


Notice how THIN the new DISA o-ring is:


Notice the new DISA o-ring is contiguous with the valve ring:

Note: I'll cross reference this nice autopsy to some of these threads for others to find:
- Why check the DISA at 85K miles to 90K miles or whenever the airbox is removed (1) (2) & how to repair a rattling DISA unit (1) (2) (3) & why the DIfferenzierte SAuganlage ("Differential Air Intake") valve flap breaks (1), sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) & how the disa valve o-ring fails (1) (2) & how it can cause all sorts of cold-engine rough idle problems (1) (2) & where to get just the DISA valve o-ring (1) & how the DISA valve operates (0) (1) (2) (3) (4) & an example of how a broken DISA valve can ruin your engine (1) & how to test DISA operation (0) (1) (2) (3) (4) & how to install an M54 DISA DIY (1) & a nice DISA autopsy (1) (2) & yet another seemingly complex set of misfire codes reputedly traced to a broken DISA valve (1)

Last edited by bluebee; 10-14-2011 at 01:26 AM.
Reply With Quote
  #3  
Old 10-02-2011, 08:34 AM
Fudman's Avatar
Fudman Fudman is offline
Officially Welcomed to the 'Fest
Location: Sudbury, MA
 
Join Date: Apr 2007
Posts: 6,225
Mein Auto: '02 530i Sport auto
Nice analysis, CSI Teklord!
Reply With Quote
  #4  
Old 10-02-2011, 09:25 AM
teklord69 teklord69 is offline
Officially Welcomed to the 'Fest
Location: Irvine, CA
 
Join Date: Apr 2010
Posts: 755
Mein Auto: 1993 BMW 318i
Quote:
Originally Posted by bluebee View Post
A few questions come to mind as I look at the nice photos:
Q1: Where does the DISA get its vacuum (there is no vacuum hose connection, for example so, does it 'make' its own vacuum)?
Q2: What happens when you put 12 volts DC to your DISA valve (presumably it will generate the vacuum to open the valve)?
Q3: Both Doru & Bazza-Aus noted the new DISA o-ring is 'ribbed and glued' while the old DISA o-ring is flattened; did you see the same phenomenon with your old & new DISA?

BTW, would you kindly compare the before-and-after closeups of the rectangular-cross-section o-ring side by side?
No vacuum hose. There is a nipple that sucks air inside the valve.. Not sure what the electrical connection really does. I know that the spring and rubber piece is what creates the pressure for the rod to go up and down. Anyone care to chime in?

The new DISA O-ring is ribbed like that to create a one-time seal. Im guessing it flatens out shortly after you put in along with the heat of the engine. Thats what I said, its a one time deal once you take it out of the engine.

I could be wrong. Since this is new part#, it could be the major change is a flat ring vs. a ribbed one.. Who knows.
__________________
2003 E39 530iA Titanium Silver w/ Sport Package
Reply With Quote
  #5  
Old 10-02-2011, 11:22 AM
champaign777's Avatar
champaign777 champaign777 is online now
Officially Welcomed to the 'Fest
Location: Champ
 
Join Date: Nov 2009
Posts: 2,051
Mein Auto: 2003 530 Sport Twins
moderator

please change the name of forum

bimmerDISA.com

Last edited by champaign777; 10-02-2011 at 11:25 AM.
Reply With Quote
  #6  
Old 10-02-2011, 04:32 PM
gchand's Avatar
gchand gchand is offline
Officially Welcomed to the 'Fest
Location: sarasota
 
Join Date: Jun 2007
Posts: 144
Mein Auto: 03 530i sport
valve gets its vacuum by being connected to the intake manifold I'm guessing.
Reply With Quote
  #7  
Old 10-08-2011, 06:59 PM
AnotherGeezer's Avatar
AnotherGeezer AnotherGeezer is offline
Hofmeister Kink
Location: ManchVegas, New Hampster
 
Join Date: Dec 2009
Posts: 3,797
Mein Auto: 2003 530i/5
Quote:
Originally Posted by gchand View Post
valve gets its vacuum by being connected to the intake manifold I'm guessing.
Not at all. The vacuum is part of the dampening for the DISA. It's self contained.
__________________
Reply With Quote
  #8  
Old 10-08-2011, 10:34 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,248
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by AnotherGeezer View Post
Not at all. The vacuum is part of the dampening for the DISA. It's self contained.
I'm confused since there is no vacuum hose going to the DISA, yet, people say it works on vacuum.

Does the 'motor' on the aft end of the DISA generate vacuum to turn the valve?
Reply With Quote
  #9  
Old 10-09-2011, 06:27 AM
AnotherGeezer's Avatar
AnotherGeezer AnotherGeezer is offline
Hofmeister Kink
Location: ManchVegas, New Hampster
 
Join Date: Dec 2009
Posts: 3,797
Mein Auto: 2003 530i/5
It doesn't actually "work" on engine vacuum. The flapper valve is dampened by a spring and a air-tight bellows. That system forms resistance at a set rate to the air flow in the intake manifold. In my case, the bellows had failed and the flapper valve moved freely within the DISA housing therefore offering no resistance to the air flow.

Think vacuum secondaries on a Holley carb.
__________________
Reply With Quote
  #10  
Old 10-09-2011, 03:14 PM
pshovest pshovest is offline
Officially Welcomed to the 'Fest
Location: DE
 
Join Date: Dec 2009
Posts: 573
Mein Auto: '10 535iA, '00 528iTM
Precisely. There is a small ~1/16 dia hole on the intake side of the DISA, inside the circular profile gasket. It seems to be a passage into the recctangular box. This box seems to be a vacuum reservoir. The solenoid valve is likely a 3-way type .....it applies vacuum to the actuator (when energized) or it vents this vacuum to atmosphere when de-energized.

Bluebee, how's your resealed DISA holding up? Have your lean codes stayed away?

Paul S
BMW CCA 69606

Quote:
Originally Posted by gchand View Post
valve gets its vacuum by being connected to the intake manifold I'm guessing.
Reply With Quote
  #11  
Old 10-09-2011, 05:24 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
Quote:
Originally Posted by pshovest View Post
Precisely. There is a small ~1/16 dia hole on the intake side of the DISA, inside the circular profile gasket. It seems to be a passage into the recctangular box. This box seems to be a vacuum reservoir. The solenoid valve is likely a 3-way type .....it applies vacuum to the actuator (when energized) or it vents this vacuum to atmosphere when de-energized.

Bluebee, how's your resealed DISA holding up? Have your lean codes stayed away?

Paul S
BMW CCA 69606
Yep, this is 100% correct. The large plastic box is the vacuum reservoir. The 1/16" hole leads internally to a 1/4" round pipe. In this pipe is a white filter screen that when removed holds a 1-way check valve in place. ( See the OPS first photo.) This way when you stomp on the throttle and vacuum goes to near zero, the DISA works of the vacuum in the reservoir.
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm

Last edited by gtxragtop; 10-09-2011 at 05:25 PM.
Reply With Quote
  #12  
Old 10-09-2011, 06:35 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,248
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by pshovest View Post
Bluebee, how's your resealed DISA holding up? Have your lean codes stayed away?
I tested my CCV and re-inserted my DISA; yet the large set of lean codes remain!
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

Quote:
Originally Posted by gtxragtop View Post
In this pipe is a white filter screen that when removed holds a 1-way check valve in place.
Is this what you guys are referring to?
Attached Thumbnails
Click image for larger version

Name:	filter_screen_disa.jpg
Views:	21581
Size:	374.4 KB
ID:	296466  
Reply With Quote
  #13  
Old 10-09-2011, 07:29 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
Quote:
Originally Posted by bluebee View Post
Is this what you guys are referring to?
Yes, inside of the plastic pipe/tube underneath the white filter is a one-way valve. If you look on the DISA valve side (intake manifold side) you will note a small 1/16" hole.
...
...
As for your lean codes, I noticed on my 03, that the vacuum tubing is deteriorating. for example, the small hose from the fender well to the air hose between the MAF and the other
air hose that goes to the throttle body was not looking too good. So I replaced it and in doing so I noted by bending it is cracked wide open. You may have a cracked hose
somewhere leaking air. The tubing BMW used like most of the other plastics is not of a good American brand tubing like Gates.
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm

Last edited by gtxragtop; 10-09-2011 at 07:36 PM.
Reply With Quote
  #14  
Old 10-09-2011, 07:40 PM
AnotherGeezer's Avatar
AnotherGeezer AnotherGeezer is offline
Hofmeister Kink
Location: ManchVegas, New Hampster
 
Join Date: Dec 2009
Posts: 3,797
Mein Auto: 2003 530i/5
Quote:
Originally Posted by gtxragtop View Post
This way when you stomp on the throttle and vacuum goes to near zero, the DISA works of the vacuum in the reservoir.
Nope. Engine vacuum does not affect DISA operation. Air flow across the flapper valve is regulated by spring tension and dampened by a bellows within the DISA. The more air flowing by the flapper valve the more it opens.

There is no interaction between engine vacuum and the DISA valve whatsoever.
__________________
Reply With Quote
  #15  
Old 10-09-2011, 07:47 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
Quote:
Originally Posted by AnotherGeezer View Post
It doesn't actually "work" on engine vacuum. The flapper valve is dampened by a spring and a air-tight bellows. That system forms resistance at a set rate to the air flow in the intake manifold. In my case, the bellows had failed and the flapper valve moved freely within the DISA housing therefore offering no resistance to the air flow.

Think vacuum secondaries on a Holley carb.
I think I'm understanding your statement but I believe you are wrong. The secondaries work off vacuum. There is a small spring in the bellows that keeps the secondaries closed and provides for controlled opening rates. When you mash the throttle at low RPM, you end up with low vacuum. The secondaries will not open. As the RPM increase, so does vacuum and then the secondaries start to open. They open with vacuum. At low RPM when you mash the throttle, the secondaries do not open and hence no bog.

In the case of the DISA, it works off controlled vacuum. The 2 wires on the DISA are connected to a vacuum solenoid. It either blocks the passage of vacuum or allows it based upon the commands from the ECM.
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm
Reply With Quote
  #16  
Old 10-09-2011, 08:23 PM
AnotherGeezer's Avatar
AnotherGeezer AnotherGeezer is offline
Hofmeister Kink
Location: ManchVegas, New Hampster
 
Join Date: Dec 2009
Posts: 3,797
Mein Auto: 2003 530i/5
Perhaps a primer on venturi vacuum versus manifold vacuum is in order.
__________________
Reply With Quote
  #17  
Old 10-10-2011, 02:18 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,248
Mein Auto: 02 BMW 525i M54 auto 130K
It would be nice to have a definitive explanation on what exactly is opening the flapper valve, and how ...

Quote:
Originally Posted by gtxragtop View Post
You may have a cracked hose
somewhere leaking air.
I don't disagree. The problem is finding it ... I'll look, one by one:
- How to locate all the vacuum hoses in the E39 engine bay (1)
Reply With Quote
  #18  
Old 10-10-2011, 05:34 AM
pshovest pshovest is offline
Officially Welcomed to the 'Fest
Location: DE
 
Join Date: Dec 2009
Posts: 573
Mein Auto: '10 535iA, '00 528iTM
This is wrong.
The DISA flapper is either fully open or fully closed. There is no intermediate position on a properly working DISA valve. A DME controlled solenoid uses manifold vacuum to close DISA flapper and spring action to open the DISA flapper.

Paul S
BMW CCA 69606



Quote:
Originally Posted by AnotherGeezer View Post
Nope. Engine vacuum does not affect DISA operation. Air flow across the flapper valve is regulated by spring tension and dampened by a bellows within the DISA. The more air flowing by the flapper valve the more it opens.

There is no interaction between engine vacuum and the DISA valve whatsoever.
Reply With Quote
  #19  
Old 10-10-2011, 08:39 AM
AnotherGeezer's Avatar
AnotherGeezer AnotherGeezer is offline
Hofmeister Kink
Location: ManchVegas, New Hampster
 
Join Date: Dec 2009
Posts: 3,797
Mein Auto: 2003 530i/5
Quote:
Originally Posted by pshovest View Post
This is wrong.


Paul S
BMW CCA 69606
I stand corrected Paul. My vacuum secondary comparison was also off. After much research I found this to be the best DISA operation decription I could find.

"The disa valve has an outer seal (inside the manifold) and a diaphragm inside the valve itself. The valve is constantly fed 12 volts during normal throttle operation and then open circuits on higher RPM and throttle opening. This deenergises the coil which stops the manifold vacuum from reaching the diaphragm. The butterfly then springs open."

Do you concur?
__________________
Reply With Quote
  #20  
Old 10-10-2011, 11:38 AM
pshovest pshovest is offline
Officially Welcomed to the 'Fest
Location: DE
 
Join Date: Dec 2009
Posts: 573
Mein Auto: '10 535iA, '00 528iTM
AG,
Actually I'm partial to the description in posts 10, 11 and 18 of this thread. However your research has found a description that is also consistent with my observations. The mystery to me was the vacuum source. I had my M54 DISA out for inspection recently and discovered the 1/16" port. My 129k DISA is fully functional, no loose or broken parts, no play in linkage, diaphragm holds vacuum, solenoid is functional. Another dose of form-a-gasket and I reinstalled it.

Paul S
BMW CCA 69606


Quote:
Originally Posted by AnotherGeezer View Post
I stand corrected Paul. My vacuum secondary comparison was also off. After much research I found this to be the best DISA operation decription I could find.

"The disa valve has an outer seal (inside the manifold) and a diaphragm inside the valve itself. The valve is constantly fed 12 volts during normal throttle operation and then open circuits on higher RPM and throttle opening. This deenergises the coil which stops the manifold vacuum from reaching the diaphragm. The butterfly then springs open."

Do you concur?
Reply With Quote
  #21  
Old 10-10-2011, 06:47 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
Quote:
Originally Posted by AnotherGeezer View Post
Perhaps a primer on venturi vacuum versus manifold vacuum is in order.
Just to be clear, the venturi have nothing to do with the opening or closing of the secondaries on a Holley carb. The venturi are used to create a low pressure area that allows atmospheric pressure to force the fuel to dribble (metered by the jets) into the carb throttle bore. When the butterflies are closed, there is minimal airflow across the venturi. No airflow, no low pressure zone, no fuel flow. As you open the butterflies, the airflow increases across the venturi, and out flows the fuel. The purpose of the choke is to create a low pressure zone at starting cranking speeds that results in engine manifold vacuum sucking out the fuel through the venturis. Remember at low cranking speeds, there is little airflow.

The Holley vacuum secondaries work as I described. The Carter AVS used on Mopars has a choke like spring loaded flapper valve on top. The spring tension is adjustable. The Rottenchester Quadrabogger (Rochester Quadrjet) had a similar design. Both relied on this choke like air valve to enrichen the mixture to prevent bogging when you stomped on the gas and the mechanical secondaries opened up. The Carter AFB and the Eldelbrock Performer series have the flapper valve between the butterflies and the venturi. It's sole purpose is to not allow full airflow when you mash open the secondaries to prevent bogging. The flapper has a fixed counter-balance weight on it. There is no adjustment.
Lastly there are the double-pumper mechanical secondary carbs. Like the primaries, they use a small pump to squirt extra fuel into the secondary bores when the butterflies are opened quickly. As airflow increase across the venturi, the fuel flows.
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm
Reply With Quote
  #22  
Old 10-10-2011, 06:57 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
Quote:
Originally Posted by bluebee View Post
I don't disagree. The problem is finding it ... I'll look, one by one:
- How to locate all the vacuum hoses in the E39 engine bay (1)
Found this http://blog.bavauto.com/8443/bmw-m52...084-p1085-etc/

And this on the Mt 330I forum. The photos are simply wonderful. Worth going through these on the various pages.
http://forums.my330i.com/showthread.php?t=8770&page=15
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm

Last edited by gtxragtop; 10-10-2011 at 07:47 PM.
Reply With Quote
  #23  
Old 10-10-2011, 07:16 PM
gtxragtop's Avatar
gtxragtop gtxragtop is offline
Officially Welcomed to the 'Fest
Location: Mass
 
Join Date: Feb 2008
Posts: 877
Mein Auto: 2003 530IA
DISA theory... Takes a bit to carefully look at the diagrams. DISA valve is close to the engine side of the diagram.
http://2.bp.blogspot.com/_LzEU1X_t40...ntake1copy.jpg
http://3.bp.blogspot.com/_LzEU1X_t40...M54Intake2.jpg
http://2.bp.blogspot.com/_LzEU1X_t40...M54Intake3.jpg

I also found this (thanks to the my 330I forum) See post #92 This is the same diagrams with some text. Great stuff.
http://forums.my330i.com/showthread....d.blogspot.com

So based upon this description, with the engine not running put a mark on the external rod from the vacuum dashpot to the DISA valve. Start the engine and let it idle.
The mark should have moved since engine vacuum allowed to enter the dashpot will pull the DISA valve closed.
__________________
Ever wonder why 5 series electrical issues are common and complicated.. Spend time here and you will understand why. http://www.bmw-planet.com/diagrams/r...9new/index.htm

Last edited by gtxragtop; 10-10-2011 at 07:22 PM.
Reply With Quote
  #24  
Old 10-10-2011, 10:17 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,248
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by gtxragtop View Post
Review:
  • Title: BMW M52TU and M54 Lean Mixture Fault Codes DISA Valve? (P0174, P0171, P1084, P1085, Etc.)
  • Vehicle: 2002 BMW 530i
  • Diagnosis: Lean fuel mixture
    • Vacuum leak on intake
  • Visually check for:
    • rubber upper and/or lower intake boot
    • the plastic F vacuum hose connector on the boot
  • Run a smoke test to visually check for leaks in:
    • All vacuum hoses
    • oil-separator/check-valve system for the crankcase ventilation system
    • the throttle-body gasket
    • the intake manifold gaskets
    • and the various smaller vacuum hoses that run under the intake manifold.
  • Check the DISA
    • The flap door breaks and the valve no longer properly controls the intake air flow through the manifold.
Notice this article says that the DISA valve flap malfunction can cause lean codes. This is surprising (to me) since I 'thought' we determined the lean codes aren't from the broken flap but from a leaking o ring.

Q: What's the consensus on 'how' the DISA causes lean fuel mixtures?
Attached Thumbnails
Click image for larger version

Name:	cvv_repair_kit.jpg
Views:	97
Size:	13.5 KB
ID:	296650   Click image for larger version

Name:	disa_valve.jpg
Views:	124
Size:	11.0 KB
ID:	296651   Click image for larger version

Name:	intake_boot_and_hoses.jpg
Views:	82
Size:	17.6 KB
ID:	296652   Click image for larger version

Name:	intake_manifold_gaskets.jpg
Views:	86
Size:	17.7 KB
ID:	296653   Click image for larger version

Name:	throttle_body_gasket.jpg
Views:	93
Size:	15.9 KB
ID:	296654  

Reply With Quote
  #25  
Old 10-10-2011, 10:51 PM
teklord69 teklord69 is offline
Officially Welcomed to the 'Fest
Location: Irvine, CA
 
Join Date: Apr 2010
Posts: 755
Mein Auto: 1993 BMW 318i
Quote:
Originally Posted by bluebee View Post
Review:
  • Title: BMW M52TU and M54 Lean Mixture Fault Codes DISA Valve? (P0174, P0171, P1084, P1085, Etc.)
  • Vehicle: 2002 BMW 530i
  • Diagnosis: Lean fuel mixture
    • Vacuum leak on intake
  • Visually check for:
    • rubber upper and/or lower intake boot
    • the plastic F vacuum hose connector on the boot
  • Run a smoke test to visually check for leaks in:
    • All vacuum hoses
    • oil-separator/check-valve system for the crankcase ventilation system
    • the throttle-body gasket
    • the intake manifold gaskets
    • and the various smaller vacuum hoses that run under the intake manifold.
  • Check the DISA
    • The flap door breaks and the valve no longer properly controls the intake air flow through the manifold.
Notice this article says that the DISA valve flap malfunction can cause lean codes. This is surprising (to me) since I 'thought' we determined the lean codes aren't from the broken flap but from a leaking o ring.

Q: What's the consensus on 'how' the DISA causes lean fuel mixtures?
I am still leaning on my broken DISA flap that cause the lean codes. I have read that link as well as many others on the E46 sites where replacing the DISA got read of the lean codes. Up until now my car hasnt got any codes since replacing the DISA.
__________________
2003 E39 530iA Titanium Silver w/ Sport Package
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 01:11 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms