UPDATED::: Z4M S54 Engine Hesitation - POLL

[Anonymous]

Mine has started to deteriorate. I have done around 5000 miles since cleaning it. I am getting the first taste of the flat spot / hesitation when transferring from overrun to moderate throttle at an RPM less than 1200.

It is nowhere near as bad as it was before cleaning the ICV but it is not as good as it was in the 3000 miles immediately after cleaning.

In the last 2000 miles, my idle has started to dip and hunt around slightly when returning to idle from a throttle opening, which it did not do before. I think all these symptoms are those of an ICV which is getting sick.

I will clean the ICV once again and this time, remove the rubber pipes so I can get as good access as possible to it. I may bathe it in petrol for a few hours.

If this does not sort it, I will need to purchase a new ICV.

 

[Shooter]

Mines still good, 4000 km or so later.

 

[stealthy21]

Cheers for the info Sniffer! I want to get mine sorted and for the majority in this thread, cleaning the ICV seems to do the trick for a semi-permanent basis (5000 miles would probs last me a little over a year or more!) So looks like that's my next step, just didn't want to pay for something and it not do anything at all haha

 

[Anonymous]

Cheers for the info Sniffer! I want to get mine sorted and for the majority in this thread, cleaning the ICV seems to do the trick for a semi-permanent basis (5000 miles would probs last me a little over a year or more!) So looks like that's my next step, just didn't want to pay for something and it not do anything at all haha

I think we can conclude that this issue is caused by a non-optimal ICV (Idle Control Valve). It is likely that the cause is carbon and soot clogging up the ICV over a period of time.

Cleaning the ICV resolves the issue but the ICV will eventually clog up again in time.

I am going to do mine again shortly. This time I will remove the pipework from the ICV and attempt to give it a much more thorough clean than I did before.

 

[TomK]

What I find really interesting with this issue is that the S54 in the e46 M3 application does not suffer from this problem. Hence I find looking for solutions in common shared parts such as the ICV fairly pointless.

I had an E46M3 for 2 years and did not experience the issue that I experienced with my MC which I picked up 6 months ago. I hadn't come across any other 46 owners with this issue either.

I had a pretty much full engine rebuild recently (whilst installing Schrick cams) and I no longer have either the idle drop or hesitation issue, which were both fairly obvious. Clearly that would suggest my initial statement was incorrect since only mechanical parts have been replaced/serviced (common all I believe). So what is going on here? I've done 2000 miles or so since then and assuming this must be some kind of ecu issue seeing as this is the only difference I know of between applications. SO whilst I have no symptoms as of yet I'm expecting it to return And what of the guys&gals that don't get this problem at all?

 

[Anonymous]

What I find really interesting with this issue is that the S54 in the e46 M3 application does not suffer from this problem. Hence I find looking for solutions in common shared parts such as the ICV fairly pointless.

I had an E46M3 for 2 years and did not experience the issue that I experienced with my MC which I picked up 6 months ago. I hadn't come across any other 46 owners with this issue either.

I had a pretty much full engine rebuild recently (whilst installing Schrick cams) and I no longer have either the idle drop or hesitation issue, which were both fairly obvious. Clearly that would suggest my initial statement was incorrect since only mechanical parts have been replaced/serviced (common all I believe). So what is going on here? I've done 2000 miles or so since then and assuming this must be some kind of ecu issue seeing as this is the only difference I know of between applications. SO whilst I have no symptoms as of yet I'm expecting it to return And what of the guys&gals that don't get this problem at all?

The E85/86 Z4M S54 and the E46 M3 S54 applications use totally different engine management systems.

The Z4M uses the E60M5 MSS70 ECU wheras the E46 uses the older Siemens MSS54.

This means there is different mapping and actuator behaviour which would include the way the idle control system is handled.

This could explain why this issue did not seem to affect the E46 M3.

 

[TomK]

What I find really interesting with this issue is that the S54 in the e46 M3 application does not suffer from this problem. Hence I find looking for solutions in common shared parts such as the ICV fairly pointless.

I had an E46M3 for 2 years and did not experience the issue that I experienced with my MC which I picked up 6 months ago. I hadn't come across any other 46 owners with this issue either.

I had a pretty much full engine rebuild recently (whilst installing Schrick cams) and I no longer have either the idle drop or hesitation issue, which were both fairly obvious. Clearly that would suggest my initial statement was incorrect since only mechanical parts have been replaced/serviced (common all I believe). So what is going on here? I've done 2000 miles or so since then and assuming this must be some kind of ecu issue seeing as this is the only difference I know of between applications. SO whilst I have no symptoms as of yet I'm expecting it to return And what of the guys&gals that don't get this problem at all?

The E85/86 Z4M S54 and the E46 M3 S54 applications use totally different engine management systems.

The Z4M uses the E60M5 MSS70 ECU wheras the E46 uses the older Siemens MSS54.

This means there is different mapping and actuator behaviour which would include the way the idle control system is handled.

This could explain why this issue did not seem to affect the E46 M3.

Indeed, that's what I'm thinking. but does that suggest that a ZM's ICV gets 'dirtier' than an E46's or that the ecu is more sensitive to 'dirt' on it?
Strange :?

 

[AndyBeech]

It's definately something to do with the ECU, maybe it's more sensitive and adapts itself over time I'm not sure. It's certainly a more powerful ECU than in the E46's and more complex, in what way is hard to say. Here's what I've done to back up this theory:

I had a very slight dip in revs originally and from time to time a slight hesitation. The kind of mis-fire from idle when you blip the throttle also. A little annoying rather than actually affecting the drive to be honest, but I'm a bit of a perfectionist and went about trying to sort it, quite a lot of money spent later and these are my results so far (in order of having them done):

So, I replaced the two TPS sensors on the engine with new BMW parts, noticed no difference to be honest although the TPS sensors that came off were slightly discoloured but no particular signs of wear. Car covered a fair few miles and no difference.

Booked in the car with BMW to have the ECU updated to the latest software. Took a few hours, gave me the paperwork of the procedure, all good. Went to start the car for the first time (from cold) it noticebly felt different straight away, not in a good way though. The throttle blip from idle seemed worse and when pulling away the engine stalled. Never had this before, was like the throttle pedal input barely registered and it hesitated and stalled. Didn't happen again but on the drive home the rev dip when engaging the clutch was also much worse dipping to around 500rpm before catching, this was pretty consistant.
So this ECU reset in effect had made matters much worse, which seemed strange! Now whenever started from cold, it has a bad tendency to stall if you don't give it enough power, when warm though it won't stall at all, just the Rev dip and slight hesitation still. And also unlike before the ECU update it can take a long time to crank from cold before it starts. This seems to have improved recently though...bizarre!

Since then installed a Gruppe M filter and cleaned the MAF, no change there.

I've tried lots of differenct petrols, Tesco 99, Shell V Power and BP, none change the charicteristics.

I've brought a new ICV from BMW for £250 which is getting fitted at some point by James at Redish Motorsport. He's going to have a general look around as well and see if he can get to the bottom of it. I'll report back after this. I'm not convinced it is this tbh, for some reason I keep thinking the O2 sensors. They have been replaced on my car before by the previous owner at about 43k miles, currently on 65k miles. Using Dashcommand on the IPhone with the ODB dongal plugged in, the 02 sensors both seem to have normal readings while driving so not so sure it is that. No EML fault codes registered either. I'm positive this comes down to a faulty sensor somewhere though rather than an ECU 'fault' as such. Still, I'll wait for the results from the new ICV.


I have read elsewhere that the ICV function is controlled by a number of other sensors on the engine including the TPS sensors, 02 sensors which could explain why others have had some success when changing these sensors. I haven't changed the throttle pedal TPS sensor yet though although this does involve changing the whole unit, another expense!

 

[Arietis]

Hi Guys

I am very interested in this thread and I have read the complete 12 pages of it aper:

Very good information on it and as most people that find this thread I have the hesitation issue. My case it doesn't bog the engine down its just annoying and makes pulling out of a stop light a more delicate proposition because the engine does not always follows you command.

Hei AndyBeech how did the ICV replacement went I am very curiouse

 

[AndyBeech]

Hi Guys

I am very interested in this thread and I have read the complete 12 pages of it aper:

Very good information on it and as most people that find this thread I have the hesitation issue. My case it doesn't bog the engine down its just annoying and makes pulling out of a stop light a more delicate proposition because the engine does not always follows you command.

Hei AndyBeech how did the ICV replacement went I am very curiouse

Did nothing. I would recommend taking the whole intake manifold apart and giving all the bits, including the ICV a good clean as it will no doubt improve things if it's dirty. Save your money on replacing the ICV though, unless it really is broken (which is virtually impossible I imagine) put it towards something more useful

TOMK, you said you had an engine rebuild almost, did anything get replaced on the intake side or mostly the actual engine block side? Can you remember what was replaced exactly? (Vanos...etc?)

 

[TomK]

TOMK, you said you had an engine rebuild almost, did anything get replaced on the intake side or mostly the actual engine block side? Can you remember what was replaced exactly? (Vanos...etc?)

Another 3k in and no sign of the issue at all still. The engine had no work done on the intake side or ICV or Vanos as far as I am aware. I'll have to double check but work included, cams & followers, new head and sump gasket, big end & rod bearings, arp rod bolts, plugs, coils. Everything on the block side was cleaned in a hot tank. No sensors replaced.

Reinstalled with standard airbox (not cleaned at all) and ecu, then around 2k miles later a custom map and CSL airbox. Both scenarios have not produced the large hesitation issue I had before.

Mysterious!

 

[masz4m]

Hi,

First post here...

I've been reading this tread for over a year, have also read all other such threads on other forums that relate to this problem with M3 and Z4Ms (mine's a Z4MR, 2007). I've been wanting to write a detailed post but realizing that I'll probably never have time for it. So, here's some quick and dirty info, hope it helps:

What did not help, in no particular order (most work done by dealer or reputable indy):
- Replaced front TPS sensor
- Replaced rear (on throttle actuator) sensor
- Replaced throttle actuator
- Replaced gas pedal
- Cleaned MAF sensor (couple times)
- Cleaned all of throttle & intake related parts that could be dirty.
- Resets of all sorts all along - throttle adaptation, fuel adaptations, etc.
- Engine rebuild (leaking head gasket and worn bearing - considered maintenance by some, problem found via blackstone labs oil analysis) - So, this basically means all components were taken off cleaned, etc, etc, etc, and put back.....
- Full smoke testing - no leaks found
- Fuel injector cleaners like Chevron Concentrate
- New MAF sensor (replace twice, cause I thought one may have been damaged during shipping and returned it)
- Some other stuff I'm forgetting now, will update later if I remember.

So, while none of the above fixed my hesitation problem, it did go away many times after a part was replaced or some work got done. But, it would come back. So, this got me thinking that it has to be something to do with moving stuff around or connecting/disconnecting/etc.. At some point the problem temporarily went away after I only "checked" all the intake hoses/etc. So, then I did this again once and it fixed the problem for a few days. Looking near the intake area there are a few small hoses and couple electrical connections and such, one of them is the MAF sensor. By using trail and error, I narrowed down the problem to the MAF connector. I then tried many different things to improve the contact between MAF sensor and it's connector, each one proved that I had finally found the culprit. Following are some of the things I have tried and the results:

- 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.

 

[Arietis]

Great post masz4m

I will try this and get back with the result.

 

[Arietis]

So here is the result.

I took the plug and the MAF and cleaned it with brake cleaner.
Gave a little nudge on the plug contacts so that they would grip the pins on the MAF tighter

Some facts/happenings

1-it doesn't stutter if I disconnect the MAF connector.and also no engine light ON
2-When I connected everything the first time there was still some brake cleaner in the plug and the thing just went hay wire! It ran super erratically. My bad.
3-took the plug again and let it dry better.
4-Put it back and after some initial hiccups it seemed to stabilize.
5-when reeving from idle it will respond as fast as I would expect it (not as fast as GSX-R though ) but on the way down(the needle) 1 out 3 or 4 times it will dip below the idle just a bit.
6-It was a pain to get the plug all the way in on the 3rd try.

While Driving: Did a small run and the getting on the power is much smother, less jerky.

So far the stuttering is gone.

Going out again to triple check and enjoy the M coupe on a sunny day without stuttering.

 

[masz4m]

Please do not use brake cleaner you may cause more damage in the long run, only use electrical contact cleaner (every auto parts store will have some).

Also, if it is not clear. I am recommending that you also use a contact enhancer after you clean the contact - like stabilant or DeoXIT GOLD:

stabilant: http://www.amazon.com/Stabilant-5ml...&qid=1417882149&sr=8-1&keywords=stabilant+22a
(you will need to mix this with 99% isopropyl alcohol so buy online at the same time you may not find it locally)

DeoxIT cleaner and protector 2 in 1 kit: http://www.amazon.com/Caig-Connector-Enhancer-Protector-DGN5MS-15/dp/B00C6BTQVA
(It looks like they also have a version of the gold contact enhancer that you can apply with brushes and another in a tube, you may want to get that instead of the spray)

...and another caution that if you are not careful when spraying you could damage the yellow rubber seal to the point that you will have to cut it out (not really a big deal to me, I will find another way to seal the connector or just clean more often).

 

[masz4m]

I forgot to mention a few thing in my first post here:

Valve adjustment made no difference

Replacing air filter made no difference

Some background on the car: got it at 25k miles while it was still under warranty, started noticing the hesitation at around 40K miles, many trips to the dealer with no solution before all the other work was done that I mentioned in my first post - over the past year and last 15K miles. Currently have 85K miles on the car

I also tested some of the old parts that were replaced:
- I tested the original two TPSs after replacing them and they were both ok and performed same as the new parts. Did not know how to test the gas pedal TPS so simply replaced that part, this was done separate from other work done on the car so that's how I can tell it did not make any difference and the original part was probably ok too.
- Took apart the throttle actuator, did not find any worn gears or any other sign of wear/breakage.

Once the problem got fixed, i also noticed that the gas mileage got better (another 1.5 mpg), low end torque was significantly improved - I actually think the car is better now than when I first got it at 25K miles. Car is overall easier to drive in terms of shifting, I'm guessing that's because of improved low end torque and a consistent power delivery.

If I have time, I will do some more experiments with the old MAF connector to see if individual female connectors have expanded to the point where they are unable to make good contact with the sensor side. If this is the case then I may have the same problem with the new connector at some point.

This is probably the most important thing I forgot to mentions: I was lucky that I found a used replacement connector from my friends at the local BMW shop, it is not sold as a separate item and you have to buy the complete engine wiring harness! However, after a LOT of search and cross-referencing part numbers I found the exact part here: http://www.powerfuluk.com/products/range-rover-l322-rear-light-connectors-pair---with-wiring.html. This is for a range rover but looks to be the same exact part as in our cars - all the part/material numbers match the OEM part as well.

Oh, and I had a local car audio shop replace the connector for me. I am good with such stuff but there is no way I could have done this as well as they did - you really cannot tell where they cut/spliced at all, they used proper weatherproof connectors and sealing tapes and the same exact loom as OEM. So, there is no sign left that the connector was ever replaced.

 

[masz4m]

One more thing...

After you clean/treat the connector, it can take a few trips before you start seeing the full performance/torque improvement. However, in my experience/case, the hesitation issue is solved right away along with some increase in low end torque. If you have the right tool/SW you can use it to reset DME adaptations (I'm not talking about throttle adaptions), I use BMWLogger: http://bimmersoftware.com/bmwlogger. I have the paid version since I was planning on data logging to see what's going on with the car at the time of hesitation, you can use the free version for clearing DME adaptation, you just need the cable.

I also want to clarify that I'm not suggestion everyone's problem is the same as mine, some could have a bad sensor or other part or something. At the same time, this is one of the simple/quick/cheap things you can try before further diagnosis.

 

[TomK]

Excellent work, hopefully this is the solution so many have been looking for.
It also chimes in with the fact that I no longer have this issue and may well be linked to not having a maf and associated wiring from the alpha-n tune for my box.
Here's hoping your solution is correct as I do fear it reoccurring.
Cheers

 

[Shiro_se]

I have a 2007 USDM Z4M with ~128000km on it. I just purchased it this spring from a fellow who always maintained it very well, as did the previous two owners. Full documentation was provided with the sale.

The RPMs have always dipped just after starting and in warmer weather it's never been a problem. However, in weather near 10degC or lower, the dip is so pronounced that it will stall. After restarting 3 times it will finally stay running. First time I encountered this phenomenon, I foolishly revved the engine somewhat excessively and it started to run very rough and was very underpowered. I shut it down and left it overnight and it started fine the next day, albeit a bit roughly and with some smoke. It's been fine since, except for the cool weather starting issues.
The PO put Redline 10W60 in it before I bought it and I plan on putting the Castrol TWS in in the spring. I suspect an oil issue. I also suspect plugs and coils may be in order and plan on going with NGK Iridiums and the performance coils from Turner Motorsports.

This simple MAF Connector fix is also now on the list and will probably be the first thing I try when I take the M out of storage in springtime.

Anyone have thoughts or insights on these plans?

Thanks in advance.
Leigh

Edit: I meant to include that although I haven't experienced what I would call hesitation, I have experienced the 'kangarooing' when trying to drive smoothly at moderate pace. I am not familiar with these engines, so the hesitation may or may not be present.

 

[Shiro_se]

Coils will be from Bavarian Autosport, not TMS.