UPDATED::: Z4M S54 Engine Hesitation - POLL
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Anonymous
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Dirty throttle discs, springs and inlet tracts prior to cleaning.
Idle control valve and rubber pipework removed for cleaning.
Dirty idle bypass channels from throttle bodies to idle by pass air rail (6 of) removed for cleaning.
Mole grips used lightly on throttle actuator to gently hold throttle in wide open position to allow cleaning throttle discs and ports.
Throttle discs and inlet tracts now nicely accessible for cleaning.
Idle by pass air rail cleaned up.
Throttle discs and inlets all cleaned.
Throttle discs and inlets all cleaned. Idle control valve and pipework all cleaned and re-fitted.
Using slip grips to fasten throttle body fastening clips. Tightest setting to do up and medium to loose setting to undo. I managed to re-use 4 of them and had to buy 2 new ones. Just under £3 each at the dealers.
A tiny bit of WD40 onto O rings at either end of idle by pass channels. Here I am doing the top of them to ease the fitment of the idle by pass air rail.
Idle control valve and rubber pipework removed for cleaning.
Dirty idle bypass channels from throttle bodies to idle by pass air rail (6 of) removed for cleaning.
Mole grips used lightly on throttle actuator to gently hold throttle in wide open position to allow cleaning throttle discs and ports.
Throttle discs and inlet tracts now nicely accessible for cleaning.
Idle by pass air rail cleaned up.
Throttle discs and inlets all cleaned.
Throttle discs and inlets all cleaned. Idle control valve and pipework all cleaned and re-fitted.
Using slip grips to fasten throttle body fastening clips. Tightest setting to do up and medium to loose setting to undo. I managed to re-use 4 of them and had to buy 2 new ones. Just under £3 each at the dealers.
A tiny bit of WD40 onto O rings at either end of idle by pass channels. Here I am doing the top of them to ease the fitment of the idle by pass air rail.
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Anonymous
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Adam D said:
The idle by pass air rail is very easy to remove. Just pop off the central rubber air pipe connector coming from the idle control valve and remove the two bolts at either side which hold the idle by pass air rail to the injector rail. The one nearest the bulkhead you need a UJ for. Then just pull the rail firmly upwards evenly and it pops off the 6 idle by pass channels O rings.
Once you have the rail off you can remove the 6 channels from the throttle bodies for cleaning also.
sniffer said:Idle control valve and rubber pipework removed for cleaning.
Nice write up and good pics
I did the same job a while ago but was struggling to clean the actual internals of the idle control valve.
How did you manage this? Did you take it further apart than shown in the picture, if not how were you able to clean it?
The connected hoses prevent proper cleaning IMO.
Cheers,
René
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Anonymous
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Rene_Z4MC said:Nice write up and good pics
I did the same job a while ago but was struggling to clean the actual internals of the idle control valve.
How did you manage this? Did you take it further apart than shown in the picture, if not how were you able to clean it?
The connected hoses prevent proper cleaning IMO.
Cheers,
René
I agree with you that the connected hoses stop a really thorough clean. I did not disassemble it further than shown in the pictures, although I was tempted to do so.
It would be easy to disassemble it further; just use a flat blade screwdriver to lever up and open the metal clip holding the rubber pipe on each side of the idle control valve and then remove the pipes.
You would then have full access to the idle valve itself and the removed pipework.
When reassembling, just use a couple of decent quality jubilee clips instead of the clips you prize off.
In this instance, I left it as shown in the picture with the pipework connected. I used 3/4 of a can of Carb / Intake Cleaner using the small tube nozzle attachment, poked it down each rubber pipe and blasted a load in there:
I then rocked the valve slightly from side to side so the liquid kept flowing through the valve. Then turned the valve around so the liquid came out the other pipe. I kept doing this until the liquid flowed freely and was not so dirty in colour. It came out black for the first few goes.
I used Wynns Air Intake and Carb Cleaner Spray to start with and then ran out. The local motor factors unfortunately did not have another can so I got the Valvoline shown above. I preferred the Wynns stuff and would recommend this over the Valvoline.
Just driven the car again and it is brilliant now. Also, interestingly my idle is now higher on a cold start than previously so something is now working differently post clean up.
The car now idles at 1200RPM now on a cold start whereas before the clean it was 1000RPM. Warm idle is unchanged at 800RPM.
NB. Anyone attempting this or something similar, please make sure that your ignition is off and kept off until everything is reconnected. If you switch on the ignition before the air flow meter is reconnected for example, you will immediately have a fault logged in the DME and the engine management light will come on, requiring a reset to put it off again.
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Anonymous
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Something further I have noticed is that the car now behaves differently on the over-run.
When you are in gear and off the throttle, the engine braking is as it was down to 1100RPM upon which the behavior is now different to how it was before.
Before the clean up the level of engine braking would be the same from 1500RPM down to the 800RPM idle speed. Now the engine braking has reduced significantly under 1100RPM.
I believe this to be related to the idle control system functioning differently now. Probably DME drives the idle control valve to open as the engine revs come down to prevent a stall and then retracts it quickly to bring the engine speed down to the desired idle speed. The DME fueling MAP would obviously be expecting this behavior and fuel accordingly.
I think this has finally cracked this annoying issue. I would not have thought it likely that such a nasty flat spot / hesitation could be resolved through a clean up. I don't know what was actually causing it because I cleaned the idle control system pipework, throttle bodies and injector ends.
To clarify what I did and the outcomes:
Updating the DME to the latest software version resolved the unruly warm up behavior and noticeably improved general driveability for me.
Cleaning up the intake system as detailed above has completely eradicated what was an annoying flat spot / hesitation issue transferring from overrun at low RPM (less than 1100RPM) to moderate throttle. It would feel for a second like the car was going to break down before the car lurched forwards as if it had been hit up the ars3. Very unpleasant and embarrassing with passengers. If you revved the car in neutral, it would also sound and feel a little bit like a misfire / very slight hesitation when stabbing the throttle from idle.
I am very happy. The car now runs brilliantly. There is no sign of the hesitation on the overrun nor when revving the car in neutral. It is like having a different car.
When you are in gear and off the throttle, the engine braking is as it was down to 1100RPM upon which the behavior is now different to how it was before.
Before the clean up the level of engine braking would be the same from 1500RPM down to the 800RPM idle speed. Now the engine braking has reduced significantly under 1100RPM.
I believe this to be related to the idle control system functioning differently now. Probably DME drives the idle control valve to open as the engine revs come down to prevent a stall and then retracts it quickly to bring the engine speed down to the desired idle speed. The DME fueling MAP would obviously be expecting this behavior and fuel accordingly.
I think this has finally cracked this annoying issue. I would not have thought it likely that such a nasty flat spot / hesitation could be resolved through a clean up. I don't know what was actually causing it because I cleaned the idle control system pipework, throttle bodies and injector ends.
To clarify what I did and the outcomes:
Updating the DME to the latest software version resolved the unruly warm up behavior and noticeably improved general driveability for me.
Cleaning up the intake system as detailed above has completely eradicated what was an annoying flat spot / hesitation issue transferring from overrun at low RPM (less than 1100RPM) to moderate throttle. It would feel for a second like the car was going to break down before the car lurched forwards as if it had been hit up the ars3. Very unpleasant and embarrassing with passengers. If you revved the car in neutral, it would also sound and feel a little bit like a misfire / very slight hesitation when stabbing the throttle from idle.
I am very happy. The car now runs brilliantly. There is no sign of the hesitation on the overrun nor when revving the car in neutral. It is like having a different car.
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Anonymous
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BMWZ4MC said:
I have looked around and could not see anything. They are set up differently though, for example the E46 has a different, older engine management system.
The Z4M apparently has engine management derived from the S85 engine - M5 and M6 V10 motor.
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Anonymous
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Lower said:
I am very pleased to report that after 500 miles the car is absolutely perfect.
The hesitation / flat spot / low RPM overrun to throttle kangaroo which is described above is totally gone.I am not entirely sure what the actual problem was, I think it is either related to the idle by pass valve system or perhaps the ends of the fuel injectors.
In any case, the clean up I described above is a solution to it. If I were to do it again, I would remove the idle by-pass rubber piping from the valve itself so you are able to thoroughly clean the valve body itself. You would then need a couple of (decent quality) jubilee clips to re-assemble as the BMW fixings are one time fix, throw away jobbies.
It may be worth the original poster updating the thread because it has the clean up down as a non-solution to this issue. For me it was the cure.
For the record, as you will see in this thread, I also replaced both TPS's to try and cure this issue but the symptoms came back shortly after (adaptation reset likely gave short term fix).
I am very happy with the car now. Anyone who has this issue, get it sorted because it really does ruin the drive of the car.
sniffer said:
Thanks for the update
I have been following this thread closely since mine also suffers from this hesitation issue every now en then. Already replaced both TPSs which like you said improved it a bit but not fully cured the issue, your write up gives me hope again
Last time I didn't clean the idle control valve since I didn't want to damage the original hose clips, but now its off to shops for some decent clips and re-do the job.
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Anonymous
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Rene_Z4MC said:sniffer said:
Thanks for the update
I have been following this thread closely since mine also suffers from this hesitation issue every now en then. Already replaced both TPSs which like you said improved it a bit but not fully cured the issue, your write up gives me hope again
Last time I didn't clean the idle control valve since I didn't want to damage the original hose clips, but now its off to shops for some decent clips and re-do the job.
Hi Rene,
I spent a lot of time using the WYNNS Intake Cleaner to clean not only the idle control valve but the throttle valves and inlet throats (when throttle valves held at WOT as shown in my pictures).
By the end, the throats and both sides of the throttle butterflies were gleaming clean. It is quite possible that the tips of the fuel injector(s) which are pointing into the throats were given a thorough clean in the process.
I took off the idle control valve this afternoon and flushed it through with carb cleaner. I didn't clean anything else.
I'm pleased to report that my flat spot has also gone and the slight hesitation on blipping the throttle has also gone
I'll have to wait until Tuesday morning to find out if the rough running around 2k revs when the engine is cold has gone but otherwise it feels like a new engine!
Not to hard a job either. Removing the clips on the inlets is the hardest but I managed to get them all off and reuse them using sniffers slip grips technique.
If this fix sticks (and I think it will) I would like to buy sniffer a beer
I'm pleased to report that my flat spot has also gone and the slight hesitation on blipping the throttle has also gone
I'll have to wait until Tuesday morning to find out if the rough running around 2k revs when the engine is cold has gone but otherwise it feels like a new engine!
Not to hard a job either. Removing the clips on the inlets is the hardest but I managed to get them all off and reuse them using sniffers slip grips technique.
If this fix sticks (and I think it will) I would like to buy sniffer a beer
A
Anonymous
Guest
If you did not clean anything else up and only worked on the idle control valve, that must be the actual root cause of this issue.
I was unsure because I cleaned up everything including the ends of the fuel injectors so although I thought it could have been the idle control valve I could not be 100 percent sure this was the ultimate cause.
What is this rough running issue? Mine had a cold running issue which made the car behave nastily until the coolant temperature was up above 50 degrees c. (I can see this through my Intravee). Coolant gets to 50 degrees c within two or three minutes, so quite quick and then the issue would go away.
Mine was like a jerkiness misfire kangaroo type feeling when being in gear and on the throttle accelerating. This was resolved for me by the DME update I did.
I subsequently stumbled upon a BMW PUMA case for the S54 Z4M which was about poor cold running and the fix was DME software update.
I was unsure because I cleaned up everything including the ends of the fuel injectors so although I thought it could have been the idle control valve I could not be 100 percent sure this was the ultimate cause.
What is this rough running issue? Mine had a cold running issue which made the car behave nastily until the coolant temperature was up above 50 degrees c. (I can see this through my Intravee). Coolant gets to 50 degrees c within two or three minutes, so quite quick and then the issue would go away.
Mine was like a jerkiness misfire kangaroo type feeling when being in gear and on the throttle accelerating. This was resolved for me by the DME update I did.
I subsequently stumbled upon a BMW PUMA case for the S54 Z4M which was about poor cold running and the fix was DME software update.
That was exactly i why i cleaned the idle control valve in isolation. My butterflies were pretty clean and the injector tips looked like new. The idle bypass rail was a bit dirty but certainly not blocked in any way. However, a few reasonable sized lumps of muck came out of the idle control valve with some pretty dirty solvent at first.
The rough running issue is exactly the same as you describe. Rough idle and a really lumpy spot arount 2k revs until the engine warmed a little. It disappeared when the ecu had all its adaptions cleared but came back after 1000 miles or so. I'd speculate that the DME didn't fix the problem, just cleared all the adaptions likewise.
I didn't clear the adaptions when i cleaned the idle control valve, but the rough running when cold problem seemed to have gone. I'll know for sure when i go to work on tuesday morning when the car has been standing all night.
It's quite possible that the idle control valve has been sticking in the open position and therefore messing up the air/fuel ratio. That would explain a lot....
The rough running issue is exactly the same as you describe. Rough idle and a really lumpy spot arount 2k revs until the engine warmed a little. It disappeared when the ecu had all its adaptions cleared but came back after 1000 miles or so. I'd speculate that the DME didn't fix the problem, just cleared all the adaptions likewise.
I didn't clear the adaptions when i cleaned the idle control valve, but the rough running when cold problem seemed to have gone. I'll know for sure when i go to work on tuesday morning when the car has been standing all night.
It's quite possible that the idle control valve has been sticking in the open position and therefore messing up the air/fuel ratio. That would explain a lot....
Car ran perfectly again this morning from cold and perfectly when warm.
If it stays as it is i shall be really happy.
Even when the engine was warm it used to feel like the engine needed to 'take a breath' before giving the power when i put my foot down if the revs were below 2k. That feeling has totally gone. Driving around town is much easier too as the engine responds to the slightest press of the throttle with no hesitation. I would occasionally stall the engine when manoeuvring because i'd press the accelerator very gently to get a slight increase in revs and use the clutch at the same time. Sometimes the clutch would bite just as the engine hesitated and it would stall.
I'm really pleased. I've had this problem since i got the car 2 years ago, tried various fixes and ended up driving round the problem. At the moment it feels like a new car. If the improvement isn't sustained i think i'll be fitting a new idle control valve.
If it stays as it is i shall be really happy.
Even when the engine was warm it used to feel like the engine needed to 'take a breath' before giving the power when i put my foot down if the revs were below 2k. That feeling has totally gone. Driving around town is much easier too as the engine responds to the slightest press of the throttle with no hesitation. I would occasionally stall the engine when manoeuvring because i'd press the accelerator very gently to get a slight increase in revs and use the clutch at the same time. Sometimes the clutch would bite just as the engine hesitated and it would stall.
I'm really pleased. I've had this problem since i got the car 2 years ago, tried various fixes and ended up driving round the problem. At the moment it feels like a new car. If the improvement isn't sustained i think i'll be fitting a new idle control valve.
Sounds good! Really happy to hear that a solution finally appears to be found. Mine does not do it anymore but i've had a LOT of things replaced and cleaned by my mechanic during my recent rod-bearings troubles (and even prior to that), so i simply did not know which of the many things he did had the desirable effect...