Intermittent loss of oomph

[Asiah119]

I noticed this starting in maybe a week ago or so. Moreso under spirited, but not flat out accel I would be going on my merry way and then around the 4k mark I'd hit a highly noticeable slump and then the power would be back on in full. I also noticed a slight, fraction of a second power loss while driving last night cruising at highway speeds. Thoughts? No CEL, fuel filter is new. VANOS might be rattling a bit but I have to really pay attention to notice it.

[Avetiso]

Debate incoming in 3, 2, 1...

Anyways, people will say you need the "Jersey Fix" which is essentially BMW flashing new software to your DME to fix the issue. There is evidence, however, that all they do is disable the DISA. On the other hand, I've updated to the most recent mainstream software and had my DISA and VANOS fixed and still had the issue, as do many other ZHP owners.

You can never fully get rid of it. You may flash a tune that minimilizes it, but a dyno run will always show a dip that 4,000rpm.

[mbeckel]

Debate incoming in 3, 2, 1...

Anyways, people will say you need the "Jersey Fix" which is essentially BMW flashing new software to your DME to fix the issue. There is evidence, however, that all they do is disable the DISA. On the other hand, I've updated to the most recent mainstream software and had my DISA and VANOS fixed and still had the issue, as do many other ZHP owners.

You can never fully get rid of it. You may flash a tune that minimilizes it, but a dyno run will always show a dip that 4,000rpm.
I think it boils down to each engine being a little different from one to another.

[Asiah119]

The only thing that has me sketchy about this being "the" dip. Is that I'm doing my standard driving and this is new; pronounced enough for me to think that I'm letting off of the gas, or that the clutch is slipping; and that it feels quasi similiar to when I get fuel starvation when I'm on the track.

[Avetiso]

I think it boils down to each engine being a little different from one to another.
They are all designed the same. I think enough people have the issue that we can consider a design flaw.

[Newjack]

Debate incoming in 3, 2, 1...

Anyways, people will say you need the "Jersey Fix" which is essentially BMW flashing new software to your DME to fix the issue. There is evidence, however, that all they do is disable the DISA. On the other hand, I've updated to the most recent mainstream software and had my DISA and VANOS fixed and still had the issue, as do many other ZHP owners.

You can never fully get rid of it. You may flash a tune that minimilizes it, but a dyno run will always show a dip that 4,000rpm.
God the last thing I want is New Jersey doing anything to my car.

Maybe I'm just not observant enough, but I don't notice a 4k dip in my car. VANOS has been fixed with the besian seals and my disa valve has been fixed with the G.A.S. kit.

No New Jersey required.

[az3579]

The power dip you all are referring to is not what he is describing. The "power dip" hardly has any real effect on actual acceleration. What he is describing is a complete loss of power at that area of the power band. Fuel starvation is not fun; if it feels like that, then almost all of the power (if not, all of it) is gone for that brief moment. It's literally as though you completely took your foot off the throttle...

[TheFinanceGuy]

I have to agree with Botond on this one.

OP- what is the current mileage? Could be a failing fuel pump, or pressure regulator.

[Asiah119]

In the low 89k range.
Would be nice if the car would throw a code at me.

[PdZHP]

I had similar symptoms until this weekend when my car would just not start, no codes either. Fuel pump is dead, should be installing the new one this afternoon. I am about 70k miles as well.

[slater]

running the tank low often will wear a pump out faster, or so i've heard. it makes sense since the fuel cools the pump.

but under 100K miles is pretty weak for a dead fuel pump. i had 325K miles on the original fuel pump in my old 1996 Audi S6 - to my knowledge it is still working.

peter

[Asiah119]

Sidebar that my economy has seen a drop. Used to average 31/2 mpg w mainly Highway driving now, my most recent tank w 380miles gave me 27.9. I've also seen some jumpy idle at cold starts.

[ELCID86]

Is say start with the fuel pump. Easy DIY. I have similar (but not the same?) issues. Justin suggested I try Vanos gaskets.


Thumbs, iPhone, Tapatalk.

[Asiah119]

I'm Def going to pull a couple of plugs to see if they've gotten fried. I think I'm going to limit this to three or four fixes and then I'll have to decide how annoyed I am with the problem.

I was half able to replicate the acceleration problem. It's worst in second when I'm at 3/4 or so in the gas. If it's the DISA it's bad because the car feels mushy in the 4-4.7 range.
I may just be noticing things that aren't uncommon in that also, the car is jerking (sometimes) when I let off the gas to coast. Like all of a sudden the back pressure is catching. Idk. I may just be crazy.

[ELCID86]

^not crazy, just tuned into the car. Two others drove my car and one kind of noticed and the other not really. I do almost every time I drive it.

[Asiah119]

I guess I'll start with replacing the DISA and see what that nets me. Has anyone else run into the sloshy feeling in the 4-5 range when not at full throttle. When Im not mashing the gas first has a brief ugly spot in the mid 4 range, and then get a definite lul in second that lasts ~700revs.

[LivesNearCostco]

Dynoed my car 4 or 5 times in 4.5 years and there is always a dip around 4,000 RPM but it's never been something I could feel in the butt dyno, either before or after standard DME update (not the New Jersey update) or Shark Injector.

[Asiah119]

Got the new DISA yesterday and popped it in. On my commute in I didn't notice the uglyness that was happening before. The old DISA had gook peppered all over it and was pretty stiff in comparison to the new one. I guess it was just having trouble opening\closing and was messing up the airflow in the manifold and killing power.

[ELCID86]

Got the new DISA yesterday and popped it in. On my commute in I didn't notice the uglyness that was happening before. The old DISA had gook peppered all over it and was pretty stiff in comparison to the new one. I guess it was just having trouble opening\closing and was messing up the airflow in the manifold and killing power.

So it was an easy fix!?


Thumbs, iPhone, Tapatalk.

[NorCalZman]

Got the new DISA yesterday and popped it in. On my commute in I didn't notice the uglyness that was happening before. The old DISA had gook peppered all over it and was pretty stiff in comparison to the new one. I guess it was just having trouble opening\closing and was messing up the airflow in the manifold and killing power.

Now that that is taken care of, do you have the 4k rpm dip on hard acceleration that some have complained about?

[Asiah119]

I've honestly not really done any hard acceleration yet. My commute doesn't give me many opportunities to punch it from a stop (esp in an area with a speed limit high enough for me to get to the top of second). I can say that I still have a bit of what seems like a jump in power starting in the 5k range.

There is a bit of a.... je ne sais quoi... where, cruising at high way speeds the engine is happier; more responsive going up hills. Now all I need is to do the VANOS refresh and I'll probably feel like I have ea brand new engine.

[Asiah119]

So it was an easy fix!?

Assuming that that's all that its going to take it was pretty simple. Two torx and the unit is loose. I was lazy and didnt take the intake boot off so I struggled a bit with getting the lower torx off, and space was a smidge tight. So I suppose that technically it can be done with only taking the airbox off.

[ELCID86]

Assuming that that's all that its going to take it was pretty simple. Two torx and the unit is loose. I was lazy and didnt take the intake boot off so I struggled a bit with getting the lower torx off, and space was a smidge tight. So I suppose that technically it can be done with only taking the airbox off.

Good deal. And that is some nice finagling to get that lower one off with removing the breather box, etc. I"m alwasy afraid I'm going to drop the torx bolt...