UPDATED::: Z4M S54 Engine Hesitation - POLL

[Beedub]

my car with it's speed density tune ( alpha N) has never had such issues.....

 

[simonlpearce]

In mine it seems this only happens when pulling away slowly. For example if waiting at a roundabout and you think you see a gap then back off as its not a gap then when i go again it jumps. Decent number of revs and its absolutely fine. Its certainly worse when cold and rarely happens when warm.

I reckon a decent map on a rolling road would probably cure it.

 

[beanie]

Seeing the post on snugging up the MAF connectors jogged my memory about a thread I read a little while back. Not sure if it's appeared on this thread already but if not...

http://forum.e46fanatics.com/showthread.php?t=856781

Don't bother reading it all, the first few pages contain most of the info.

Seems some have had reasonable success doing this (although on E46s) so perhaps this is a weak point for BMWs of this era. Might also be worth doing other connectors as mentioned in that thread (vanos, CPS, TPS etc) if just doing the MAF doesn't do anything. I think also I'd heed the warnings from that thread and be careful not to over crimp anything.

Still, given all that and what masz4m says, perhaps this could fix a few.

I think I'll leave mine until the next time anything comes apart. Its been behaving quite well recently and given how others have described it, I don't think I have it bad at all-it's only on throttle blips where I occasionally find it to fumble.

I may get the besian seals for the solenoid pack though as it can only be of benefit and I'll be changing the sparks soon too.

 

[AndyBeech]

Great info chaps, wish I'd found the contact cleaner fix earlier! Will give it a try at the weekend and post results, along with the Beisan VANOS overhaul

 

[PASZ4Mc]

Hi All,

I have only just joined this forum due to finding this topic as I thought it is worth sharing my experience.
Firstly, the car, it's a 2007 '56 Z4MC. 68,000 miles with full main dealer service history and it's in very good condition. I have now owned the car for 9 months after buying it as a BMW AUC.

The car has had minimal use since I have bought it as it's kept for weekends etc. Anyway, a month or so after purchase, I noticed revs from idle didn't feel right. Essentially, once revved, the engine then seems to dip below idle when slowing down, and then "bounces" back to idle. almost stalling sometimes. I returned the car under warranty to have this looked at, only to be told the was no issues. This seems to have got progressively worse making the car difficult to drive. Particularly at low parking speeds as it regularly wants to stall. So took the car in again to BMW and physically took one of the technicians out to the car to show him. He agreed it wasn't right and set about investigating what was up. I also forwarded this forum thread to see it could be of any help. The dealer has been very helpful and has tried many of the theories mentioned within this thread (TPS x2, ICV clean/replace, coil packs etc etc. No joy.

They have now had the car for 2 weeks and using the diagnosis from my car and this thread apparently a technical case has been raised with BMW to further investigate and highlight as a problem. I still have no outcome as to what may be the cause.

If anyone is interested as to what happens I'm happy to keep updating?

Cheers.

 

[beanie]

Please do, would love to hear what BMW have to say about this.

Strange that the falling idle issue isn't resolved by changing the ISV/ICV. This happens all the time on old k-jet golfs and afaik, its the valve thats to blame. Perhaps there is an air leak somewhere if the valve has been replaced and it still happens. Or, as mentioned before, perhaps the ICV pipework/system is a bit gummed up?

 

[AndyBeech]

I suspect they'll come back with the old 'it's a quirk of the engine, highly tuned, aggressive cams etc etc.'

There's many parts that can affect the idle hence why so many people have had different fixes/improvements with different new parts.
I don't think the actual ICV is ever the problem unless it just needs a good clean, which can certainly help if its never been done. I wouldn't go to the cost of replacing it though unless you can actually see that it has a fault.

Air/vacuum leak is a possibility. TPS sensors and on and on with all that's been mentioned along this thread. I don't think there's a one solution fits all personally but I'm certainly liking the idea that the connectors themselves could be to blame for some and is next on my list. Along with the VANOS overhaul next week I'm certainly hoping this will resolve my issue, otherwise I'm a bit lost having tried out most the other solutions in this thread!

 

[stealthy21]

Just got myself some contact cleaner, will probs give it a go tomorrow and report back when I can. This hesitation has been the bane of life!

 

[PASZ4Mc]

UPDATE.

Following on from my previous post, Air Mass Meter, TPS x2, leak check of air intake,ECU update, valve clearances, valve timing all checked or replaced. Still not cured.
Awaiting further direction from BMW.

 

[Ewazix]

Probably of absolutely no relevance but my R56 Cooper S had falling idle problems when cold, sometimes to a stuttering stall, hesitation on pull off and intermittent cutting out. It displayed no fault codes but after much searching it was found to be the high pressure fuel pump. A new pump & relay was fitted under warranty and the tech' commented that he had seen the same symptoms on BMW units as well, unfortunately replacement seems to be the only fool-proof method of diagnosis for an intermittent failure.

 

[stealthy21]

Hi,
- cleaned the contacts with electrical contacts cleaner - no long term fix
- applied deoxIt GOLD and their cleaner (available at RadioShack or other places online). This provided the longest lasting and biggest improvement!
- slightly twisted the terminals on the connectors with needle nose pliers covered with a shop towel to improve contact, applied deoxIT GOLD again. Voila! All is perfect now, car has never been this good! One bad thing is that the DeoxIT spray caused the yellow rubber seal inside the connector to swell making it impossible to the put the connector back on the sensor. So I had to cut the seal out.

There you have it....

Next, I found a connector from an M3 that was slightly used, replaced mine with this one that still had the seal. Replaced the MAF sensor at the same time since I had already purchased it and did not want to use my old hacked one with this new connector. Have not had time to drive the car much due to snow and salt on the road (Boston area) so can't tell if the car is as good as with the hacked sensor yet. I also purchased Stabilant 22 online which I plan to try if needed, I think this would be better than using DeOxIT Gold since this is not a spray and you apply using fine brushes. Plus, I think Stabilant 22 is also mentioned in some old threads referring to a BMW TIS where they recommend using it on sensor contacts. I will post back an update once I have it.

In short, I would recommend you try Stabilant 22 after cleaning with DeoXIT cleaner and see if it helps. You can use DeOXIT GOLD instead of Stabilant 22 but if you are not careful you may damage the seal and have to cut it out.

Best of luck.

PS: It could be that many people who got temporary good results by trying other things (like cleaning MAF, or ther parts, replacing parts, etc) actually somehow ended up moving the connector a bit or disconnecting/reconnecting it temporarily improved contact.

Was impatient and did it today...Result= SUCCESS! The car is like butter now, unbelievably smooth! You sir, are a legend! Thank you so much, you saved me quite a bit of money!

Cleaned it with a normal electrical contact cleaner a few times, got some black stuff out of the male side. Reset the DME using the above software and done, perfect. Will keep my eye on it but if it comes back I will buy the gold contact enhancer and try it that way, either way its a 2 minute jobby!

Oh, and MPG is up too!

 

[Lower]

Resetting the DME will give that effect on its own unfortunately.

See if the improvement is still there in 1000 miles

 

[gwatson]

Resetting the DME will give that effect on its own unfortunately.

How do you do this? Is it just a case of disconnecting the battery for 10 mins?

I've done the throttle adaption reset before.

 

[AndyBeech]

Resetting the DME will give that effect on its own unfortunately.

How do you do this? Is it just a case of disconnecting the battery for 10 mins?

I've done the throttle adaption reset before.

Yes probably a bit longer than 10 mins though, or use or find someone that has INPA, much easier!

Resetting the DME is kinda pointless though unless you've done some work on the engine or fitted some parts that warrant a reset.

 

[stealthy21]

The hesitation wasn't there after the clean and before the DME reset so I doubt it was just the DME reset that cleared this problem. I didn't go for a drive but from idle it felt so much better. I then cleared the DME then went for a drive to really test it.

 

[ovrkll]

Just an observation from my own car. The drop of idle was continually getting worse in my car, then the alternator gave out without any warning. Replaced the alternator and the idle issue went away. Not sure if my issue is related in any way, but having a voltage drop in this car may have an effect in idle issues.

Cheers!

 

[Meeko]

Hi all,

Yesterday I found time to clean my MAF connector. I have to say though it looked as clean as the day the car was built. Nonetheless, I used Deoxit as recommended to clean it (no dirt came off on the cloth). I also bent the contacts to ensure a better connection. It didn't make any difference at all. The revs still dropped when revving from idle (when warm), almost like a misfire. There is also still the flat spot up to around 2k RPM.

I didn't reset the DME adaptations as I suspect this is what actually makes the difference, not cleaning the connector, which is a red herring. Lets's hope that PSZ4Mc has some luck with BMW and we get to know the real cause!

 

[Lower]

Just an observation from my own car. The drop of idle was continually getting worse in my car, then the alternator gave out without any warning. Replaced the alternator and the idle issue went away. Not sure if my issue is related in any way, but having a voltage drop in this car may have an effect in idle issues.

Cheers!

What failed in the alternator? Did it seize or just stop generating? A failing bearing in your alternator which was creating more load that the idling engine had to deal with would give those symptoms.

 

[simonlpearce]

Wonder if a set of underdrive pulleys could sort the problems out?

Anyone have a set fitted?

 

[ovrkll]

Just an observation from my own car. The drop of idle was continually getting worse in my car, then the alternator gave out without any warning. Replaced the alternator and the idle issue went away. Not sure if my issue is related in any way, but having a voltage drop in this car may have an effect in idle issues.

Cheers!

What failed in the alternator? Did it seize or just stop generating? A failing bearing in your alternator which was creating more load that the idling engine had to deal with would give those symptoms.

Stopped generating