Car was throwing codes....DISA valve!

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

What were they thinking??

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

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

This is excellent information, so I cross referenced to here inside this thread:
- General diagnostic procedure for a single or multi-cylinder E39 misfire?

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

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!!

Originally Posted by uncmozo

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'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.

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)

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!

Originally Posted by uncmozo

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.

Originally Posted by uncmozo

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

Originally Posted by doru

the gasket as I understand it, might deteriorate and not re-seal properly.

Mine, at 105K miles, was pretty flattened!

Originally Posted by uncmozo

you could apply some Permatex silicone if you wanted to.

That's what I did just now.

Originally Posted by gtxragtop

Make sure you use SENSOR SAFE RTV, not silicon.

Oh oh. Did I use the right stuff?

According to the Permatex Ultra Copper Technical Data Sheet, Ultra Copper IS sensor safe. Your fine.

Jerry

Originally Posted by uncmozo

Ultra Copper IS sensor safe. You're fine.

Thanks for the legwork!

I think I'll still order a couple of DISA o-rings, just in case I need to remove it again in the near future.
- E39 (1997 - 2003) > DISA 0 Ring

Permatex Ultra Copper Maximum Temperature RTV Silicone Gasket Maker

• Permatex Ultra Copper Technical Data Sheet
• Permatex Ultra Copper MSDS

BB...After following this discussion I was trying to figure out if it worked for you. Are your codes gone now?

Originally Posted by GSA1

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?

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

Way to revive old thread with some old news. Did you know GAS is a fest sponsor? Most of us know about the kit since the developing stage.

When they start throwing codes, watch out!

Originally Posted by uncmozo

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)




...

It's GREAT to see Bluebee back...
That's all I wanted to say....

Originally Posted by EconoBox

It's GREAT to see Bluebee back...
That's all I wanted to say....

+1

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.

Originally Posted by bluebmw2003

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.

Thanks for all of this awesome information guys ... i have the codes logged and will be taking out the DISA and inspecting asap... i'll post some photos here if I find anything bad.

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: