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Old 10-20-2019, 10:34 PM   #1
Kyoki
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DISA - Could this be my problem?

Lol, I'm sure many will be coming here just to say: "Of course it is, just replace it you toad", and you're probably right. But humour me and hear me out!

I've read plenty of threads on bad disa's recently, but nothing quite covers what i'm experiencing.

I had a CEL come on recently, codes were P0171/P0174, the classic too leak codes when you've got a vac leak somewhere. I pulled off the air intake, and the top elbow to check, while doing so found that there was a tear in the little nub on the lower elbow that goes to the IACV (ICV). So obviously that needs to be replaced. There are no major issues with the car, no crazy idle - enough that you wouldn't even know it was there if the light wasn't on - in fact i'm not sure that rip is what caused the CEL. (Obviously i'll replace the Elbows anyways, i'm not stoopid).

Up until now I've had bad hesitation on take off, from the lights, or from a stop. You have to apply more throttle than you normally would and then the car will surge off. (I understand that the split in the elbow could be causing this too though) I also have a really loud - what only can be described as 'hissing' noise under the bonnet. While looking for the split yesterday I managed to narrow down the location of this. Behind the dipstick, and below the top of the intake manifold. I understand this is a common issue when the CCV needs attention, and also when the DISA is slowly dying. On top of this, when I tap the top of the DISA, it rattles. There is also a slight rattle when the engine is running (very slight). At the time of writing I haven't tried unplugging the DISA yet to see if that makes it go away.

What is the likelihood that it's the DISA that's causing the hissing, and contributing to the hesitation? I've bought one of the G.A.S rebuild kits anyway because if i'm going to have to take the DISA off to get to the lower Elbow it would seem short sighted not to at the very least replace the O ring - and if it turns out the flap is shot I can do that at the same time.

Next order of business if those two don't fix the issue will be to pull the intake off and check out the vac lines and the CCV system. Until then does anyone have any speculative suggestions as to what else could be causing my issues. Or can say with some degree of certainty that the DISA is probably a major contributor? Obviously until actually done those things it's speculation. But it would be good to know if anyone else has experienced something like this, and if so what the fix was.

Car is a 2004 325i Touring - btw.

Thanks in advance!
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Old 10-23-2019, 11:58 PM   #2
Xynnoath
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Quote:
Originally Posted by Kyoki View Post
Lol, I'm sure many will be coming here just to say: "Of course it is, just replace it you toad", and you're probably right. But humour me and hear me out!

I've read plenty of threads on bad disa's recently, but nothing quite covers what i'm experiencing.

I had a CEL come on recently, codes were P0171/P0174, the classic too leak codes when you've got a vac leak somewhere. I pulled off the air intake, and the top elbow to check, while doing so found that there was a tear in the little nub on the lower elbow that goes to the IACV (ICV). So obviously that needs to be replaced. There are no major issues with the car, no crazy idle - enough that you wouldn't even know it was there if the light wasn't on - in fact i'm not sure that rip is what caused the CEL. (Obviously i'll replace the Elbows anyways, i'm not stoopid).

Up until now I've had bad hesitation on take off, from the lights, or from a stop. You have to apply more throttle than you normally would and then the car will surge off. (I understand that the split in the elbow could be causing this too though) I also have a really loud - what only can be described as 'hissing' noise under the bonnet. While looking for the split yesterday I managed to narrow down the location of this. Behind the dipstick, and below the top of the intake manifold. I understand this is a common issue when the CCV needs attention, and also when the DISA is slowly dying. On top of this, when I tap the top of the DISA, it rattles. There is also a slight rattle when the engine is running (very slight). At the time of writing I haven't tried unplugging the DISA yet to see if that makes it go away.

What is the likelihood that it's the DISA that's causing the hissing, and contributing to the hesitation? I've bought one of the G.A.S rebuild kits anyway because if i'm going to have to take the DISA off to get to the lower Elbow it would seem short sighted not to at the very least replace the O ring - and if it turns out the flap is shot I can do that at the same time.

Next order of business if those two don't fix the issue will be to pull the intake off and check out the vac lines and the CCV system. Until then does anyone have any speculative suggestions as to what else could be causing my issues. Or can say with some degree of certainty that the DISA is probably a major contributor? Obviously until actually done those things it's speculation. But it would be good to know if anyone else has experienced something like this, and if so what the fix was.

Car is a 2004 325i Touring - btw.

Thanks in advance!
Honestly, I've been chasing the exact same issue. I just recently acquired my 330xi and have been dealing with a laundry list of things that the previous owner neglected to handle.

1st gear take offs SUCK in this car. I've been driving manual cars since I learned how to drive so I'm not terrible (not a pro by any means) but I figured I should be able to take off without the car feeling like it wants to stall every time. Occasionally I'll get a decent launch but I've been unable to pinpoint that sweet spot.

Any how, I pulled my disa valve (which at some point before I bought the car a couple of months ago managed to lose one of the two mounting bolts). My flapper and pin were in tact with no issues however the o-ring was completely compressed. The valve is supposed to have some resistance when removing / replacing it in to the manifold and mine came out with absolutely no resistance. So I swapped it with a rein one. Original disa was genuine bmw so I'm going to replace the ring and install the g.a.s kit on it and save it for later. Bought another bolt from FCP and installed it last night. All day car ran much better but was still having issues with launches about 5/10 times. I'm currently (as in right this second) removing upper and lower boots and the new disa to pull the ICV and TB to see if those are clogged or just filthy. Judging from what the cars oil looked like when I first took ownership, I'm assuming PO never cleaned or did anything as far as little maintenances. Although he did completely overhaul the cooling system in the car so I thank him for that.

After all that, if it's not fixed then I'm thinking it's time to address the vanos or ccv. What's strange though, is my car is throwing zero codes at all. Nothing stored, nothing pending, nada. But I know for a fact it's not launching properly.

I'm sorry if this wasn't much help, I'm still learning about this car since I've been all about domestics my whole life. But I figured it might give you peace of mind knowing you're not the only one.

Sorry for the novel. For all I know, it could just be the CDV that needs to be removed.....
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Old 10-24-2019, 11:44 AM   #3
Xynnoath
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By the way, a rattling disa is a critical sign that the flapper is loose and needs to be replaced. If it breaks loose and gets sucked in to the motor...well I hope you've got another motor to swap.
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Old 11-06-2019, 07:49 PM   #4
ibedoughboy
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I had a 325i touring last year with a similar issue. The owner couldn't figure it out and threw multiple coil packs and plugs at it thinking that was the problem. It would clear up when it warmed up.

I did pull the DISA and the flapper was just flopping around in the housing. Bought a rebuild kit for cheap and rebuilt it in an hour. Put it back in and ran perfect and no codes. It's a common failure, so even if it's not exactly the cause of your issues it could certainly be a contributor.
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Old 11-06-2019, 11:46 PM   #5
Xynnoath
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Originally Posted by ibedoughboy View Post
I had a 325i touring last year with a similar issue. The owner couldn't figure it out and threw multiple coil packs and plugs at it thinking that was the problem. It would clear up when it warmed up.

I did pull the DISA and the flapper was just flopping around in the housing. Bought a rebuild kit for cheap and rebuilt it in an hour. Put it back in and ran perfect and no codes. It's a common failure, so even if it's not exactly the cause of your issues it could certainly be a contributor.
+1 to that
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