Terrible loss of power 4000 rpm and beyond

[racer2086]

Hey guys. Had to ask this after today. I can't take it anymore.

When I downshift and punch it to pass someone or merge on a highway, the car pulls great until exactly 4000 rpm, where it literally feels like the car falls flat and someone is pulling against it from behind. It maybe gets mildly better higher in rpms, but the car just has nothing after 4000 rpm, that I actually shift earlier to drive it below that. The pull down below is much better.

This flat spot is way worse than the 2800-3000 rpm sputtering that I also have, and improved greatly since getting the car.

So I've read about the DISA causing this and various other things. I've seen BMW service bulletins to address this that says to replace the DISA and reflash the DME to reset the knock adaptations.

Link 1: https://forum.e46fanatics.com/showthread.php?t=285819#/topics/285819?page=2

Link 2: http://www.zhpmafia.com/forums/showthread.php?20456-BMW-Service-Bulletin-12-17-05&highlight=4000

Link 3 (fixed with new DISA only): http://www.zhpmafia.com/forums/showthread.php?21524-4k-RPM-Power-Dip&highlight=4000

My question is what should I do? Replace DISA and flash DME? Can that be done not at a dealer? It sounds like if the full flash doesn't happen, then the knock adaptations don't get reset.

[ZHPizza]

Definitely sounds like a malfunctioning DISA. I'd swap that with a used one and see what happens.

[Fried_Chicken]

You can buy a DISA valve repair kit. They’re relatively cheap, and replace the parts that tend to fail on the DISA with better ones.

This assumes the core of your DISA is ok. Check amazon or ebay to find one.

[racer2086]

Just watched a youtube video on how to test it -- apply a vacuum and then 12v to the plug. So I should probably pull the DISA and test it. I already bought o-rings to replace the original. It surely isn't leaking through that o-ring, because I smoke tested the car, but if the unit is leaking vacuum, that would be a problem. If it tests good, then I can do the rebuild.

How can I tell if the problem is just a bad DISA or the DISA-knock sensor problem that the service bulletins address? I guess just replacing/rebuilding it? (I do need to flash my DME for the 2800 rpm stumble at some point anyway.)

[Reasoned1]

The only issue my ZHP has had (in my possession) is a rattling DISA. I rebuilt with GAS which resolved the issue. If the DISA falls apart, it can cause catastrophic failure of the engine.

[racer2086]

So I pulled the DISA today to check it and make sure my engine wasn't going to ingest a metal pin. It is actually in great shape and is the updated DISA part number, which was another reason I wanted to pull it. Was relatively clean compared to some others I've seen. Pin was in good and tight. I could not pull it out. Flap is perfect with no chips. Vacuum holds the flap closed. Maybe it was replaced at some point. So for the short term here, I can drive with some peace of mind. I will order the GAS kit and plan to do that. It is clearly heavier-duty and won't fall apart.

I don't know how the old o-ring wasn't leaking (smoke test showed no leak), but it was smooshed flat. I replaced with a new o-ring, based off some measurements I found online. I bought a 25 pack of silicone o-rings from Amazon for like $8: https://www.amazon.com/gp/product/B000FMWPRE/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I had to stretch the o-ring around to get it on (wasn't too hard), but once it was on, it fit in the groove great and had just enough o-ring sticking up out of the groove to require some silicone grease on it to get it in. With a little work, I was able to push it on with my hands, instead of needing to crank it on with the screws. So I would recommend them.

Now what I'm working on is flashing the DME with Balidawg over on E46fanatics. That should hopefully fix my 2800 rpm stumble and this 4000 rpm dip.

The 4000 rpm thing is clearly related to the knock sensors and DISA valve opening, since that is specifically what the BMW service bulletin talks about:
-- Service Measure B12 209 05 dated 4/6/2005 -- states there is an improved DISA part #11 61 7 544 805 and that a "deep flash" clears the long-term knock adaptations. Link: https://forum.e46fanatics.com/showpost.php?p=3256949&postcount=12

-- Then, service measure B12 209 05 was superseded by Service Information Bulletin SIB 12 17 05
This one states not to replace any parts, but rather send the DME in for "MS45.1 DME KNOCK ADAPTATION RESET"
Link: http://www.zhpmafia.com/forums/showthread.php?20456-BMW-Service-Bulletin-12-17-05&p=536913#post536913

So that should hopefully take care of it, but I can't help wondering if this will become an issue again, as the car continues to sense the DISA opening. Has the software coding been reworked to tell it to ignore "knocks" when it is activating the DISA? That's the only thing I can think of other that BMW expecting people to keep sending their DMEs in for this adaptation reset.

[Reasoned1]

Have you ever considered a Shark tune?

[racer2086]

Have a read about the shark tune.

But I'll tell you what. I flashed the DME with Balidawg's help to the most recent BMW software and man this thing drives freaking great!!! It pulls hard and all hiccups and issues are GONE. I wish I did this day one, but wow it is a joy to drive now. It rips right up to 6000 no issue. Car feels like it gained 20-30 hp now that it doesn't have those studders and stupid dip at 4k.

Highly recommend to everyone to flash your DME. Mine was 6 versions older than the newest software, so if yours is older than that I can only imagine the improvement.

[johnrando]

Nice!

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[Fried_Chicken]

I wish cars didn’t require software updates :facepalm

[racer2086]

This was the single best thing I've done to the car in the 8 months I've owned it. Seriously, I LOVE driving this thing now. I felt since the day I got it that it was down on power, but now it rips (for 235hp) but actually feels like it has 235 hp. The Sprint booster makes it even better :thumbup

[ZHP_Brandon]

This was the single best thing I've done to the car in the 8 months I've owned it. Seriously, I LOVE driving this thing now. I felt since the day I got it that it was down on power, but now it rips (for 235hp) but actually feels like it has 235 hp. The Sprint booster makes it even better :thumbup

This is interesting. Will BMWCoder (PaSoft) tell you your dme version?


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[racer2086]

Yes it will. It's a 7 digit number under "assembly #"