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do our cars need the DISA flapper???

8K views 52 replies 12 participants last post by  220k330 
#1 ·
hey guys --- soooo, I need some help....I picked up an 01 530 on the cheap cheap...cheap --- nice car! So it runs like crap, missing like crazy. Had 12 codes, so I cleared them all, checked the coils and plugs. Coils looked ok, plugs looked like crap. But in new plugs. Cleared codes...it ran better but still crappy. Had misfires on 4, 5, and 6. Swapped coils in 1, 2, and 3, to 4, 5, and 6. Cleared codes and restarted, came back up misses on 4, 5, and 6. So, Im assuming my coils and plugs are good. Then I heard the DISA valve....yup....broken and it was sucking air. So, I went out and bought the gasket I discovered to reseal the DISA valve but the flapper was broken so I yanked it out. Reinstalled everything and it still runs like crap, and was cutting off. I blocked air flow at the MAF and it fell in it's face so I know it is not getting air from anywhere. After clearing codes and running it again it tripped P1351 0171 1349, which 4 and 5 misfires, and also a lean code.

So........the only thing I can see is the flapper on the DISA -- I sprayed down everything with brake clean and nothing changed. Checked for vacuum hoses, checked intake boots...I cant see anything cracked or pulling excess air.

I guess maybe the injectors could be bad but I doubt. I am thinking about taking the DISA out of my 330 but I REALLY dont want to.

I did some research on if our cars NEED the flapper..some say yes, some say no....so....I put it to you!
 
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#2 ·
Smart-ass answer #1: No, BMW just threw it in there for fun

Alternate answer #2: If it is already broken and you don't have the cash to replace it, just remove the flap and all related hardware and re-install the body. Make sure the seals are good or you'll just have a code.

Alternate answer #3: Yes, replace it.
 
#5 ·
Smoke test! German Auto Solutions DISA kit!

Read up on fuel injectors leaking and possibly causing an intake backfire which blows the bottom out of the intake manifold. It has happened more than a few times, and I solved a guy's problem a while back with this guess. It's just a guess though.

You appear to have a massive vacuum leak, to me.

Picture of the car. Let's see it.
 
#7 ·
I just finished smoke testing mine and i had a pretty bad misfire, cylinders 5 and 3. RPMs bounced a lot, and the car had no power. Turns out the hose that goes to the top of the crank case (brand new one, too) had a bad o ring. That was the cause of the misfire. Smoke test your car, vacuum leaks can easily cause a bad misfire. If you don't have the machine, go find a shop. My local indy lets me come in and use it, but that's cause i know them well. If you find none (you will find some i guarantee) move on to other stuff.

As far as the DISA, buy a new one
 
#11 ·
First, If you live in Savannah and are on facebook... Savannah BMW Meet

https://www.facebook.com/groups/130431353786921/

Second, If you remove the DISA flap it will just cause the car to loose low end torque. It manipulates the air flow within the intake manifold. You will need to do a smoke test and (or spray brake parts cleaner) to find that vacuum leak. The BPC will cause the engine to rev up. Blocking flow into the MAF will cause it to have false readings of air into the engine and cause it to stall. If you unplug the MAF and it runs better then you know you have a vacuum problem (or a bad MAF)
 
#18 ·
The air leaks out, not in. The system is under pressure, so if you have a leak the pressure is lowered, as it naturally wants to equalize with the enviroment...

Not so...
 
#16 ·
Lack of a DISA flap may cause some engine idle stability issues on cold start.

Cannot say for sure, but it will change the intake runner lengths and impact the air charge behavior for the cylinders.

But the broken/missing DISA flap is not likely your overall problem.

You should read the first few links below in my signature for ideas and info.
 
#20 ·
I was hoping the crushed DISA gasket was going to fix it all....so, intake boots are good, DISA is sealed....what is the next weakest link for unmetered air? The windshield is just cracked...I mean what the hell though, it cost me $750....nice car as long as I can fix it!!!!!!
 
#23 ·
the car was 750 :) Ok, so....I can not get to a smoke machine unless there is another way to do it? So, I am about 99.999999999999% sure we have an air leak. I looked at it tonight a little and I dont see anything. There is a broke hose coming out of the front of the cam case cover but it is just a breather of some sort. What I dont understand is when I cut air to the MAF it falls on it's face. I checked codes again and I had all cyl's mis-sfiring...ughhh...so...everything I can see is ok, so...do I need to pull the intake?
 
#24 ·
There is a broke hose coming out of the front of the cam case cover but it is just a breather of some sort

The crank case is under full vacuum on these engines. That hose is likely associated with your vacuum leak.
 
#25 ·
yea but when I block it off and then link it up with the other side it made zero change in the running rough. I know it has something to do with it, but it is not the main issue.

So, cant smoke it, everything I see it good. Boots are good, DISA is sealed. Where next, How ofter to the intake gaskets fail?
 
#29 ·
:facepalm:

You have been introduced to Professor Scotty, but BEWARE, the Scotty test method will only allow you to find the OBVIOUS leaks. You need a tester/tool that can continuously keep the intake/crankcase under pressure to find the smaller leaks.

If you would read the links in my signature and these links, it pretty well lays everything out that you "should" do.

Pay attention to the "BMW 20 Question" section of this thread - http://forum.e46fanatics.com/showthread.php?t=1059972

I left out some real basics like new spark plugs and so forth as I usually "ASSUME" these issues are addressed, but I am quickly learning you have to lead a horse to water, then you know the rest of that story!

http://forum.e46fanatics.com/showthread.php?t=1057387

The problem is if do not want to spend money, then you will have to cobble something together on your own.

I suspect you will be making a OCC system with heater hose and something you have laying around the garage rather than doing the right thing, but this is just my guess.

And do you have your OWN OBDII scan tool that supports Emission Readiness Monitors, Freeze Frame and Live/Realtime data? If not, you REALLY need to buy one, $20 for your smart phone will get you started.
 
#30 ·
A smoke test is easy. It will pinpoint all the leaks so you don't have to guess & chase. Guessing & chasing has cost many people more time & money than proper diagnosis ever has. Not having a smoke maker isn't really a valid reason to not do a smoke test. Smoke test it by any means necessary and get on with your life.
 
#33 ·
ok so the car is running (running like crap) I found that cracked (broken hose), I blocked it off, and then linked it up with some rubber hose I had that was big enough to seal it, and when doing that the idle did not change at all. It looks like it just expels gases/pressure from the crankcase. I understand it serves a purpose, just like the DISA flapper serves a purpose, but, neither of those two things are the root, main cause of the running issue. And, Im not going to spend any more money on it (windshield....fender....DISA....hose....) until I get her running right. The car is at my friends shop right now waiting to get smoked --- when he lets me know what he finds, I will report back!
 
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