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Car was throwing codes....DISA valve!

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126K views 44 replies 22 participants last post by  e46help  
#1 ·
About 10 days ago my car was idling very rough. Took out the Acutron scanner and got several different codes. P0171, P0174 - system too lean, bank 1 and bank 2. The car was drivable, so I cleared and re-read the codes for 2 or 3 days. I kept getting different codes, P1083, p1084, P1347, P1348, etc. Basically codes were pointing to cylinder misfires, cylinder cut-offs, and running lean. I removed the MAF (Mass Air Flow) sensor, cleaned it, and I had some very minor improvement. Checked for intake leaks at the same time, found none. Codes are still flying, so next day I changed the plugs and the #3 coil pack. #3 seemed to have the most misfires. Old plugs were in decent shape, no improvement, still throwing codes. Finally stumbled upon a post or 2 that mentioned the DISA valve.
Removed the DISA valve. BMW calls it 'adjuster unit', also have seen it called 'manifold adjuster'. The plastic hinge pin was broken on mine, so the flap was just hanging there inside the intake manifold! What a poorly designed piece of garbage. Apparently, the flap remains closed, restricting air intake, until higher RPM's, then it opens to allow more air flow. The valve is not variable, and is either all the way open or all the way closed. Mine was hanging open - running lean. I was very lucky no parts had flown off YET.
Replaced the valve (BMW - $220), problem solved - car runs great and no more codes! I would guess mine was on it's way out for some time.

Not a bad thing to check regularly, very easy to remove. Pull the air box, unplug the unit, and remove 2 #40 Torx bolts. The thing slides out towards you. Remember, the same folks that gave you the plastic impeller on your water pump, and the plastic radiator, also gave you the plastic DISA valve, with one plastic and one metal hinge pin. Deteriating parts enter your intake manifold. Brilliant!

Jerry
 
#3 ·
The thing with the Disa valve, as far as I know, is that if the unit is still good, and you remove it, you might have to cheat in order to seal the unit properly - the gasket as I understand it, might deteriorate and not re-seal properly.
Also, another element that (as far as reading different posts on different forums) can induce some "leanliness" are the manifold gaskets, which also deteriorate over time. This might be a bit more tricky to do - I don't know, I have not done it, but after reading through numerous posts, it seems that once the Disa valve seal is gone, the intake manifold seals are toast as well together with the O-rings. Here
Disa # 7
Intake manifold gaskets # 2
Distribution piece O-rins # 6
When in there, check the O-ring #4 for the Temp sensor #3 as well.
Awsome post - and maybe Donna will add this to her "How do diagnose a sudden and disturbingly unsettling cold-engine misfire - these seals when cold can contract and lead to unmeterd air in the engine, triggering all sorts of unwanted codes. The Disa valve is the cherry on the cake.

0.02
 
#4 ·
I did not have the deteriating seal issues you described, the seal is actually molded into the valve body. I'm sure you could apply some Permatex silicone if you wanted to.

My issue was the cheap plastic pin breaking. The pin not only holds the flap in place, it seems it is a hex shaped pin and it also drives the flap open and closed. Broken parts entering my intake manifold is a scary thought.

If you didn't want to remove the valve, there is a small odd-shaped cover that easily snaps off with a small screwdriver. It's on the bottom right of the rectangle that is the main body of the valve. If you pop the cover off, you can manually actuate the valve. I would guess you could actuate the valve with engine running, and diagnose if the flap is working or not. I found this out after trying to take the old valve apart.

Jerry
 
#8 · (Edited)
I did not have the deteriating seal issues you described, the seal is actually molded into the valve body. I'm sure you could apply some Permatex silicone if you wanted to.
Jerry
Make sure you use SENSOR SAFE RTV, not silicon. Silicon destroys the O2 sensors quickly.
A lambda sensor***8217;s normal life span is 30,000 to 50,000 miles, but the sensor may fail prematurely if it becomes clogged with carbon, or is contaminated by lead from leaded petrol or silicone from an antifreeze leak or from silicone sealer.

This is fine to use. Not condoning any one manufacturer here. Just citing a sensor safe example.
 

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#6 ·
I've added some pics to add to my explanation. Location of DISA valve, broken parts, and actuator with access cover removed. The metal pin mounts at the top of the flap holder. I would imagine this would hurt your intake valves and/or cylinder, and was only resting in it's mounting hole.

Jerry
 

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#7 ·
So.. you say stuff falling into your intake is a scary thought.. well to me it's an Effed up reality... Had all the same issues rough idle and what not.. ended up being my disa valve and cyclone separator.. had originally taken it to ford dealership where i bought the car, because i got an after market warranty with it. They mis diagnosed the sh*t out of it.. billed my warranty co. 2800 on all sorts of stuff that didnt need to get fixed.. so they ended up sending it over to BMW, BMW diagnosed it correctly but only fixed the disa valve.. and left the Cyclone. Cause the ford dealership was technically the customer at that point.. so after they fixed the disa valve they said the pin was missing and asked to open up the intake manifold to look for it.. The Ford dealership said no just hold off till he brings it back to get the Cyclone fixed... well before i had a chance to get down there and have it towed back to BMW, The Ford dealership started up the car two different times and let it run for a bit.. well... now my effing engine is done for.. that pin got in there and effed up 2 pistons and some other stuff in there.. yeah.. soo now i need to get a whole new engine according to BMW.. hope my warranty co understands this one or i'll be getting a lawyer!!
 
#9 ·
I think this thread has enough information to merit inclusion with the bestlinks, don't you?

- DISA VALVE FLAP BREAKS: the DISA valve flap breaks, sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) & recommended parts (1) (2) & brand selection (1)
 
#10 · (Edited)
Poolman just uncovered a great source for the DISA-valve o-ring!
- DISA 0 Ring

So, to add value, I updated the bestlinks line on the DISA:
- DISA VALVE FLAP BREAKS: the DISA valve flap breaks, sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) or the disa valve o-ring fails (1) (2) & where to get just the DISA valve o-ring (1)

What we need now is:

  • What size is the DISA valve o-ring?
  • What material is best for the DISA valve o-ring?
I googled for a few minutes; but did not find the size listed yet.

Next person - please measure the o-ring and report back to the team!
Image
 
#11 ·
got several different codes. P0171, P0174 ... I kept getting different codes, P1083, p1084, P1347, P1348, etc.
I'm here right now 'cuz I have codes of a very similar nature and a very slight stumbling while at very low RPM and usually when in the first ten minutes of driving.

For example, after clearing the night before and then going for a 10-mile drive in the morning, here are the pending codes from yesterday:

  1. P0306,BMW 243, Cylinder 6 Misfire Detected
  2. P1346,BMW 240, Misfire During Start Cylinder 3
  3. P1343,BMW 238, Misfire Cylinder 1 with Fuel Cut-Off
  4. P1083,BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
  5. P1085,BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
  6. P1349,BMW 241, Misfire Cylinder 4 with Fuel Cut-Off
  7. P1351,BMW 242, Misfire Cylinder 5 with Fuel Cut-Off
  8. P0171,BMW 227, System Too Lean (Bank 1)
  9. P0174,BMW 228, System Too Lean (Bank 2)
Then, after a few more 10-mile drives, today I have the SES and four codes, with the last one still pending:

  1. SES: P1083,BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
  2. SES: P1085,BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
  3. SES: P0174,BMW 228, System Too Lean (Bank 2)
  4. PENDING: P0171,BMW 227, System Too Lean (Bank 1)
So, I decided to take a look at the DISA valve based on what you wrote here.

very easy to remove. Pull the air box, unplug the unit, and remove 2 #40 Torx bolts.
I didn't even pull the MAF or the airbox or the ductwork. With a hinged socket set and a T40 Torx socket, you can easily remove just the two bolts and the DISA electrical connector.

Mine "seemed" to be working ... but I didn't innervate the electrical pins with 12 volts (or is it 5 volts?) to see if the valve moved to the full position:
- How to properly test for DISA valve proper operation on the BMW E39

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the gasket as I understand it, might deteriorate and not re-seal properly.
Mine, at 105K miles, was pretty flattened!

Image


you could apply some Permatex silicone if you wanted to.
That's what I did just now.
Image


Make sure you use SENSOR SAFE RTV, not silicon.
Oh oh. Did I use the right stuff?
Image
 

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#13 · (Edited)
#15 ·
Are your codes gone now?
Unfortunately, the plethora of lean-related codes are still occurring.

I'm keeping a running log of them over here:
- Does the ORDER of pcodes listed in an OBDII scanner actually matter?

Rather than replace parts, willy nilly, I'm trying to (slowly) learn how to diagnose each and every suspect until I find the culprit.

Next on the list is a systematic check of the fuel system & vacuum hose system.

Luckily, as I finish with each, I attempt to write up all the reputed tests I've found in the record, so that others don't have to do all the legwork again:

For example:
- How to test for DISA valve operation on the BMW

Regarding the title of this thread, see also:
- Why does a car "Throw" a Code?
 
#16 ·
Repair Kit for DISA

I found this kit from German Auto Solutions. Not sure if this is posted elswhere on the forums, but it worked perfectly. Serveral innovations as well. no plastic, single titanium screw and all the supplies needed to do the repair. Did my '04 Z4 3.0 in about 90 mins.
planning to do my '02 530i this weekend. DISA Repair Kit
 
#19 ·
P0171, P0174 - system too lean, bank 1 and bank 2. ...I kept getting different codes, P1083, p1084, P1347, P1348, etc. Basically codes were pointing to cylinder misfires, cylinder cut-offs, and running lean.
I realize this is an old thread resurrected - but I want to point out that I had the same (or similar) lean condition codes - and in my case, it was 'not' the DISA.

In my case, it was a hole in the lower CCV vent hose and another hole in the small corrugated boot connected to the ICV.

Here are the codes I had:

  • SET:
    • P0313 BMW 238 to BMW 243 inclusive, Misfire Detected with Low Fuel
    • P0300 BMW 62 Random/Multiple Cylinder Misfire Detected
    • P1083 BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
    • P1085 BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
    • P1349 BMW 241, Misfire Cylinder 4 with Fuel Cut-Off
    • P1351 BMW 242, Misfire Cylinder 5 with Fuel Cut-Off
    • P0171 BMW 227, System Too Lean (Bank 1)
    • P0174 BMW 228, System Too Lean (Bank 2)
  • PENDING:
    • P0313 BMW 238 to BMW 243 inclusive, Misfire Detected with Low Fuel
    • P0300 BMW 62 Random/Multiple Cylinder Misfire Detected
It's all documented here:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

Image

...
Image
 
#23 ·
Have a 2003 530. Tried to remove the DISA valve body and it is stuck. Slides off slightly but the valve flap must be stuck against the inside. How shoud i go about removing it. Thanks.
It comes out fairly easy. Have you removed the big air intake boot (downstream of the MAF)? You can take it out with the boot on, but if it's old you might crack it when you bend it to allow for the DISA to come out. Hold in by 2 torx bolts.
 
#25 ·
Well I finally had a chance to inspect mine ... the DISA was in good working order though the O-rings are a bit flattened but I think it's sealing well.

My obvious culprit was like Bluebee pointed out above: the INTAKE BOOT. The small off shoot tube was cracked in several places. I taped it until I can get a replacement which isn't too bad, about $40-50 for the new intake boot.

Here are some images:

Image


Image
 
#26 · (Edited)
Well I finally had a chance to inspect mine ... the DISA was in good working order though the O-rings are a bit flattened but I think it's sealing well.
You'll want to pick up an o-ring to replace the flattened one.
- Where to get just the DISA valve o-ring (1)

My obvious culprit was like Bluebee pointed out above: the INTAKE BOOT. The small off shoot tube was cracked in several places. I taped it until I can get a replacement
Thanks for the update, and, I love your images.
They will come in handy helping others!
Image
 

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#29 ·
First post... Owned this 03 530i about a year and a half. Thew the p0174 code last week. While attempting to remove DISA valve I have discovered that I can only get it to come out 1/4 inch... As if the flapper might be loose and catching on the manifold on the inside. Tried wiggling it no success. Don't want to pull to hard so as to break off the flapper or it's pins. Any ideas?


Sent from BimmerApp mobile app
 
#30 ·
P303 P0171 P0174 P1083 P1085 vacuum leaks & DISA repair

I have seen a few threads related to replacing a DISA due to a broken hinge pin. I think our repair is better than a new one, since the cheap plastic hinge pin is replaced with a 4" long #10 SS bolt. I have attached some pics. Let me know if you have any questions.

2003 BMW 530i with 110k miles. It started idling rough and the check engine light came on. It had the following codes:
P303 Cylinder #3 Misfire
P0171 System to lean Bank 1
P0174 System to lean Bank 2
P1083 Fuel Control Mixture Lean Bank 1
P1085 Fuel Control Mixture Lean Bank 2

We tested the vacuum system using pressure & smoke. The smoke is created by a cigarette inserted in the canister end of the the pressure hose. (the good news is we found the vacuum leaks, the bad news is that my car now has lung cancer)

When we removed the air cleaner box we found a broken mount, so we epoxied that back together.

The vacuum system test uncovered a torn intake boot and a bad seal at the DISA.

To repair the intake boot we glued it with rubber cement.

To repair the leak at the DISA valve we placed a thin coating of RTV on the 'O' ring.

When we removed the DISA vlave to repair the vacuum leak we discovered that the hinge pin was broken.

Here are the steps we took to fix it:

1. Thread the DISA butterfly door by slowly twisting the bolt in and out of the hole in the bottom. Each time you start to feel pressure back the bolt out all of the way out and blow the debris out of the hole. Then start threading again. This will take about 10 or 15 minutes.

2. Using a bit the same size as the bolt, carefully drill out the center out of what is left of the original hinge pin.

3. Thread the bolt through the old hinge pin and the butterfly door. Once the bolt is inserted and tight put a couple of drops of super glue on the edge of the head of the bolt.

4. Insert the metal pin in the other end and again place a few drops of superglue under the edge of the head. (you do not want that pin going through your engine!)
 

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#31 · (Edited)
Just had this dreaded DISA issue happen to my 2001 530i.

It was throwing all the typical codes and was getting progressively worse. At it's worst, codes included

misfires 1, 2, 3, 4, 5, 6
misfires on startup
lean bank 1 and bank 2

I started troubleshooting with the MAF first (did nothing), then took apart the airbox, inspected the upper lower intake boot, all good.

Then pulled the DISA and boom, busted plastic hinge and disa was in the open state. This problem is waiting to resolve itself while my Ebay parts ship.

Assuming this fixes my issue, great! If not, on to ignition coils, checking for vac leaks, ccv, O2 sensors, etc.

I guess my question is, if the DISA repair works and the ECU is reset does that mean the coils and other ancillary parts downstream from the DISA go back to normal operation or could they have been damaged?
 
#32 · (Edited)
wait what?,,,slow down...why are you thinking disa..disa wont cause misfires..or lean conditions.. AIR leaks will.. what are your fuel trims reading?? Take LIVE measurements on the trims and increase rpm and see if the LTFT drop..if they drop you have an air leak.

as for damage...no way... disa wont cause any damage unless the pin pulls out and trashes the piston that it fell into... all other emission stuff is safe..