[alx.]

Originally Posted by Stream

Maybe old pressure differential sensor can cause the problem?
https://www.ecstuning.com/b-genuine-...r/13628617097/
It has ~5 revisions.

Interesting, could this cause a CEL?

I've plugged in the OLD MAF, seems to run better with it....could be placebo or maybe it was the fact that the car wasn't warmed up but the rough idle is still there.

[alx.]

I have e-mailed the dealer who sold me the MAF for a replacement unit and will keep you all updated.

[Three_thirty_I]

I've often wondered about the MAP sensor (pressure differential sensor as above). But not done anything further. Not sure if there is a way to clean it, if it can even be cleaned. And I don't really have any idle issues as such. The only things that I have noticed is that when it is hot outside, the idle speed is closer to 900 rpm instead of the normal 650 rpm when it's cooler or cold outdoors. Not too long ago I had one weird experience where I had started the car from cold, and while reversing out of my garage I got a text message that I had to reply to, and while sitting with my foot on the brake but in neutral and off the throttle, the idle speed jumped to around 2500 rpm (or so) and then dropped back to normal again. This was for literally a second or so. Weird.

[alx.]

Originally Posted by Three_thirty_I

I've often wondered about the MAP sensor (pressure differential sensor as above). But not done anything further. Not sure if there is a way to clean it, if it can even be cleaned. And I don't really have any idle issues as such. The only things that I have noticed is that when it is hot outside, the idle speed is closer to 900 rpm instead of the normal 650 rpm when it's cooler or cold outdoors. Not too long ago I had one weird experience where I had started the car from cold, and while reversing out of my garage I got a text message that I had to reply to, and while sitting with my foot on the brake but in neutral and off the throttle, the idle speed jumped to around 2500 rpm (or so) and then dropped back to normal again. This was for literally a second or so. Weird.

Same thing happened to me but not to 2500 but 1200 ish. I see it's relatively cheap at around $50-60 in romania. I've sent the MAF back for a warranty claim and they will send me a new unit, too bad it's going to take a couple of weeks.

[Stream]

My engine did the same thing when i disconnected maf-sensor.

[Phil325i]

Originally Posted by Three_thirty_I

I've often wondered about the MAP sensor (pressure differential sensor as above). But not done anything further. Not sure if there is a way to clean it, if it can even be cleaned. And I don't really have any idle issues as such. The only things that I have noticed is that when it is hot outside, the idle speed is closer to 900 rpm instead of the normal 650 rpm when it's cooler or cold outdoors. Not too long ago I had one weird experience where I had started the car from cold, and while reversing out of my garage I got a text message that I had to reply to, and while sitting with my foot on the brake but in neutral and off the throttle, the idle speed jumped to around 2500 rpm (or so) and then dropped back to normal again. This was for literally a second or so. Weird.

Yes you can clean the MAP sensor (I used electrical contact cleaner) but they're not that expensive to replace. Yes, I get the rev 'jump' on cold start. I think it's part of the transition routine in the DMF software from stone cold to warming cycle. I sometimes feel a slight 'jerk' from the engine 200 or so metres down the road from a cold start (when I haven't taken a text!). Same thing.

[alx.]

Heh, starting to think these engines are designed like this.

[stewey]

Installed the new MAF last night. Sadly the idle is still rough. I'll give it a few days to adapt and think about what to do next :/

[alx.]

Originally Posted by stewey

Installed the new MAF last night. Sadly the idle is still rough. I'll give it a few days to adapt and think about what to do next :/

Damn and i was excited to get my replacement MAF. Checked for codes? If you have INPA delete the codes that should show up and run it.

[Three_thirty_I]

Originally Posted by Phil325i

Yes you can clean the MAP sensor (I used electrical contact cleaner) but they're not that expensive to replace. Yes, I get the rev 'jump' on cold start. I think it's part of the transition routine in the DMF software from stone cold to warming cycle. I sometimes feel a slight 'jerk' from the engine 200 or so metres down the road from a cold start (when I haven't taken a text!). Same thing.

Well, I should maybe price a new part for interest sake, and then just also try spraying some electrical contact cleaner into the current one to see what happens afterwards. And apart from that strange cold idle jump when it happened, there were no noticeable driving issues once I got going, so it could be that it is somehow part of the warming up cycle. Still a weird thing though.

Originally Posted by stewey

Installed the new MAF last night. Sadly the idle is still rough. I'll give it a few days to adapt and think about what to do next :/

Maybe disconnect the battery for 30 minutes or so and then see how it goes - adaptations will have to relearn with the new sensor.

[alx.]

Driven with the old MAF for three days now and no codes this car is really trolling me hard...

[Three_thirty_I]

Originally Posted by alx.

Driven with the old MAF for three days now and no codes this car is really trolling me hard...

I know that feeling! Nothing nicer than intermittent issues! I mean nothing worse of course.

[SSJTrunks523]

Love to get this pinned down. I'd rather not have to retire my winter DD :'(

[alx.]

Could it be an internal issue with the vanos/valvetronic? I'm even thinking a blown valve or two.

[stewey]

Originally Posted by alx.

Damn and i was excited to get my replacement MAF. Checked for codes? If you have INPA delete the codes that should show up and run it.

Yes, I need to clear codes and see if anything new pops. Actually, the car has been running pretty good the last couple of days. Fuel economy is awful. I'm going to give it more time, but maybe it's good enough??

[alx.]

Update: sort of random but still an update, the idle on my way to work today sat at a smooth 800 without any dips(without AC on). Usually it sits at around 600-700 and it's very erratic.

What could cause this?

[alx.]

Installed the replacement MAF but i see no improvements, still pulsating at idle. Do i need to reset adaptations or anything?

[Taskmaster]

Originally Posted by alx.

Installed the replacement MAF but i see no improvements, still pulsating at idle. Do i need to reset adaptations or anything?

Why not?

[Three_thirty_I]

I would definitely reset adaptations so that it can relearn with the new part.

[inthehat]

For what its worth my car always feels better once adaptions have been reset without changing anything else but its only short lived before the issue is noticeable again.

spotted this yesterday

https://wiki.bentleypublishers.com/d...or+fault+codes

i'm still not showing any codes.

i've now got INPA, ISTA-D+P happy to try any suggestions anyone has. what I really need but don't think it is capable of is logging live driving parameters anyone know how to do this?

[F22_Raptor]

Have you checked the Eccentric valve sensor? Its the little black cable next to coil #1. just pop it off and see if there is any oil inside.

[alx.]

Originally Posted by F22_Raptor

Have you checked the Eccentric valve sensor? Its the little black cable next to coil #1. just pop it off and see if there is any oil inside.

Checked, no oil. Even replaced the gasket for it when doing the ccv.

My friend who's a mechanic has called a guy who used to work for BMW on vanos engines and he will look into the timing chain, apparently mine was changed and there's a possibility someone goofed on the repair. I asked him to check for leaks in the manifold and if possible the valvetronic/vanos.

He mentioned a bad valve or two or even a broken spring can cause the air mass error, not necessarily the MAF itself...i hope he gets to the bottom of this