UPDATED::: Z4M S54 Engine Hesitation - POLL
- Thread starter bertman
- Start date
I'm back from this weekend's trip, totaling about 8 hours of engine running / 400 km drive, which included all sorts of driving conditions - 180+ Km/h highway speeds, steady 110 Km/h straight sections, mountain twisted roads and about 3 hours spent in traffic jams (less than 20 Km/h average).
I am glad to report that there's still no hesitation at all. I am glad that I can finally drive the car off smoothly, from a full stop.
I summed up 640 Km (400 miles) since I replaced the throttle actuator TPS, and there's no sign of hesitation coming back.
Maybe I should add more miles before claiming out that it's definitely fixed, but I am almost sure it is.
I guess that it would now be a good time for some other member of this board to buy a TPS and replace it.
Just to make sure that the TPS issue was not something particular to my Z4M. If we have a second positive feedback, then we will most likely confirm that TPS is the cause of the hesitation.
IMPORTANT: I would like to thank Karsten (user 53Fatman on this forum) from Germany for carrying over the information from the M-Forum, and to thank the unknown Germans from the respective forum who figured out the fix. They should be credited for this solution. I just replicated it, and, in my case, it worked like a charm.
I am glad to report that there's still no hesitation at all. I am glad that I can finally drive the car off smoothly, from a full stop.
I summed up 640 Km (400 miles) since I replaced the throttle actuator TPS, and there's no sign of hesitation coming back.
Maybe I should add more miles before claiming out that it's definitely fixed, but I am almost sure it is.
I guess that it would now be a good time for some other member of this board to buy a TPS and replace it.
Just to make sure that the TPS issue was not something particular to my Z4M. If we have a second positive feedback, then we will most likely confirm that TPS is the cause of the hesitation.
IMPORTANT: I would like to thank Karsten (user 53Fatman on this forum) from Germany for carrying over the information from the M-Forum, and to thank the unknown Germans from the respective forum who figured out the fix. They should be credited for this solution. I just replicated it, and, in my case, it worked like a charm.
That's great news, if I could easily remove the air intake gubbins I would have a go at this for £65 in parts and my own time in labour.
What's putting me off is getting to all those funny clips and figuring out how to release/re install them without introducing an air leak. If anyone has a step by step on stripping the air intake that would be great 8)
Did they also change the sensor on the front of the throttle bar too?
Adam
What's putting me off is getting to all those funny clips and figuring out how to release/re install them without introducing an air leak. If anyone has a step by step on stripping the air intake that would be great 8)
Did they also change the sensor on the front of the throttle bar too?
Adam
Adam, I understand your concern regarding the intake hose clamps. When I did it first time, it was quite a trouble. But as soon as I figured out how to apply the slip joint pliers on the clamps, it turned out to be very easy. You don't need to worry about air leaks, as long as you make sure they lock correctly. The clamps either lock in the correct position and ensure a proper fit of the intake manifold, or don't.
I suggest you:
- to read the TIS procedure, for example at the following link: http://tis.spaghetticoder.org/s/view.pl?1/06/29/17
- and, together with the TPS, to purchase a clamp (p/n: 11617831745). It's very cheap, and you can study how it works before you start working.
I confirm that I have not replaced the TPS located at the front of the throttle bar. I have only replaced the TPS located on the throttle actuator.
I would also say that, if this fix confirms, then the throttle actuator TPS may be considered as a wear part of the S54 Z4M engine, and may probably need to be replaced every 30,000 - 45,000 Km or so.
I suggest you:
- to read the TIS procedure, for example at the following link: http://tis.spaghetticoder.org/s/view.pl?1/06/29/17
- and, together with the TPS, to purchase a clamp (p/n: 11617831745). It's very cheap, and you can study how it works before you start working.
I confirm that I have not replaced the TPS located at the front of the throttle bar. I have only replaced the TPS located on the throttle actuator.
I would also say that, if this fix confirms, then the throttle actuator TPS may be considered as a wear part of the S54 Z4M engine, and may probably need to be replaced every 30,000 - 45,000 Km or so.
That's great work RobertRO!! and thanks bakes100 for the heads up on the discounted part
Anyone else with the problem planning on trying this out? I had my dealer test the TPS and apparently it's functioning perfectly. They reset the adaptations and replaced the MAS so it'll be a while until I know if it worked
Anyone else with the problem planning on trying this out? I had my dealer test the TPS and apparently it's functioning perfectly. They reset the adaptations and replaced the MAS so it'll be a while until I know if it worked
So, I have been having a problem with general hesitation and dipping idle when blipping the throttle.
Its got so bad that even the girlfriend noticed it
and it manifested as general bogging down when pulling away to the point where I would have to give the engine a little throttle when waiting to pull away to ensure the engine was 'ready' and not lifeless.
Also when blipping the throttle it felt a little like the engine was out of balance, almost like a small misfire on one cylinder. Car has 76k miles on the clock and has just had its second inspection 1 and valve clearances checked (within spec), car given a full bill of health.
So - following on from this thread i have tried to fault find without any throttle adaptation resetting.
Last week i brought a bottle of redex injector cleaner and put a third in on a full tank. This seemed to have some benefit as the small misfire, out of balance feeling cleared up. Although i am VERY skeptical of additives it did seem to help.
Also last week i brought 2No. TPS switches and I changed the top one at the front of the engine. I then drove the car for about 300miles (its my daily driver) and i can honestly say there was no real noticeable difference to performance or idle - still rubbish.
This weekend just gone I took some time and installed the second TPS under the intake and as suggested in this thread I cleaned the idle control valve. The ICV was pretty black and sooty but the spindle seemed to spin ok. Also whilst the intake was off i sprayed some carb cleaner in and around the throttle body openings. There was a little build up of crud in the area where the butterfly shuts and so now they are all shiny.
The results? Well after driving the car yesterday and today, probably 120miles covered, the car is definitely much, much improved. Throttle response from idle is very immediate as you would expect and on return to idle the massive bounce has totally gone. The needle now drops very slightly below the normal idle speed and then it comes up to rest. Not like the massive drop of 200-250rpm like before, its more like 25-50rpm and then its back up.
I would definitely recommend to anyone with these symptoms to go for the second TPS first and see if that makes a difference. The cleaning of the ICV is a bit of a pain as there are a few hoses that need to be removed but I think that whilst you're there its worth doing along with the throttle intakes as suggested.
Hope that helps people.
Its got so bad that even the girlfriend noticed it
and it manifested as general bogging down when pulling away to the point where I would have to give the engine a little throttle when waiting to pull away to ensure the engine was 'ready' and not lifeless.Also when blipping the throttle it felt a little like the engine was out of balance, almost like a small misfire on one cylinder. Car has 76k miles on the clock and has just had its second inspection 1 and valve clearances checked (within spec), car given a full bill of health.
So - following on from this thread i have tried to fault find without any throttle adaptation resetting.
Last week i brought a bottle of redex injector cleaner and put a third in on a full tank. This seemed to have some benefit as the small misfire, out of balance feeling cleared up. Although i am VERY skeptical of additives it did seem to help.
Also last week i brought 2No. TPS switches and I changed the top one at the front of the engine. I then drove the car for about 300miles (its my daily driver) and i can honestly say there was no real noticeable difference to performance or idle - still rubbish.
This weekend just gone I took some time and installed the second TPS under the intake and as suggested in this thread I cleaned the idle control valve. The ICV was pretty black and sooty but the spindle seemed to spin ok. Also whilst the intake was off i sprayed some carb cleaner in and around the throttle body openings. There was a little build up of crud in the area where the butterfly shuts and so now they are all shiny.
The results? Well after driving the car yesterday and today, probably 120miles covered, the car is definitely much, much improved. Throttle response from idle is very immediate as you would expect and on return to idle the massive bounce has totally gone. The needle now drops very slightly below the normal idle speed and then it comes up to rest. Not like the massive drop of 200-250rpm like before, its more like 25-50rpm and then its back up.
I would definitely recommend to anyone with these symptoms to go for the second TPS first and see if that makes a difference. The cleaning of the ICV is a bit of a pain as there are a few hoses that need to be removed but I think that whilst you're there its worth doing along with the throttle intakes as suggested.
Hope that helps people.
Need to check if I have this problem, guessing this is the part
http://www.eurocarparts.com/ecp/c/B...7fe3a68bf742c3c97873c1581f996fd7a679a6&000576
http://www.eurocarparts.com/ecp/c/B...7fe3a68bf742c3c97873c1581f996fd7a679a6&000576
Daz05 - if you want to do it the cheapest possible way then get yourself a can of carb cleaner and do the throttle bodies and the ICV for sure, i'm convinced it will help.
The only problem is, getting the intake manifold off is, well, to be honest a bit of a ball ache and whilst you are there for the sake of £40 for a TPS, you might as well change it.
Just my 2pence worth.
The only problem is, getting the intake manifold off is, well, to be honest a bit of a ball ache and whilst you are there for the sake of £40 for a TPS, you might as well change it.
Just my 2pence worth.
mad4slalom
Senior member
high po engines in the past did havelumpy tickovers and running due to hot cams etc, but is not the whole point of vanos that it constantly monitors the valve timing and engine fueling requirements and advances or retards the camshaft to give optimum performance and yet maintain driveability, with a hot cam you are stuck with that particular valve dwell and overlap so its a trade off between performsnce and drivability. :? just my understanding of it
I have replaced my TPS and cleaned the throttle bodies + ICV and about 90% of the hesitation has gone, now when I blip the throttle the initial kick is totally gone although every now and again there is a little 'fluff' but nowhere near as much as before, I may not even notice it if I wasn't looking out for it.
I am going to put some BG44K in the next tank and see if that solves it completely. Both the throttle bodies and ICV were pretty dirty.
Also a little tip for taking off the throttle body clips off, use long nosed pliers and wear a gardening glove on the hand you are using to grip the pliers, this way you can grip it harder without knackering your hand. All in all it took me about 45 mins, 20 mins of that was the cleaning.
I am going to put some BG44K in the next tank and see if that solves it completely. Both the throttle bodies and ICV were pretty dirty.
Also a little tip for taking off the throttle body clips off, use long nosed pliers and wear a gardening glove on the hand you are using to grip the pliers, this way you can grip it harder without knackering your hand. All in all it took me about 45 mins, 20 mins of that was the cleaning.
Yeah there are the visible hoses that clip in around the bottom of the plenum and also one right underneath which is just a push fit one that is removed reasonably easily.
All in all the job was easier than I anticipated, just make sure you remember the order you took everything off and don't rush it
All in all the job was easier than I anticipated, just make sure you remember the order you took everything off and don't rush it
I've bought a TPS, may get chance to fit this weekend. Did anyone write/photo a full walkthrough? I've seen a few pointers in this thread, and it sounds reasonably straightforward.
How did you clean the ICV? Did you remove the hoses and flush through with carb cleaner?
UPDATE: So far only done 40 miles, but the hesitation "appears" much improved. I only changed the TPS and have not cleaned the ICV or reset the adaptive throttle as yet. I wanted to see first if changing the TPS "only" made a difference.
How did you clean the ICV? Did you remove the hoses and flush through with carb cleaner?
UPDATE: So far only done 40 miles, but the hesitation "appears" much improved. I only changed the TPS and have not cleaned the ICV or reset the adaptive throttle as yet. I wanted to see first if changing the TPS "only" made a difference.
Update:
I have replaced the offending item and had a very brief test drive - the dead spot on the first inch of throttle travel has gone, its now immediate to rev up and feels very perky. 8) :evil: 
When the revs fall it no longer undershoots and its idling a little bit higher too - solid idle.
This has made is so much nicer to pull away without sputtering and bogging down.
Points to note:
The the technical instructions some the live electrical feed does not seem to fit to the plenum (unless its one of the main wires at the back which unhook without any fuss.
When you think everything has been undone and want to remove the air take box you will probably find a vent to the sump is still connected at the back underside of the airbox - now this won't come off the airbox like it suggests but instead get a helper to lift the box up and with a torch follow it down to the sump. Squeeze in the clip (similar to the retentions used on the breather pipes up top) and remove at the lower end - easy
My thottle butterflies were quite dirty and there was a hard residue along the lower edge of the butterfly. I cleaned them the best I could using a lint free cloth and a sturdy toothbrush and a can on Wynns carburettor cleaner. To open the butterflies and clean the back of them and inside where they shut pull the actuator rod down and then wedge a piece of wood near the top.
The airbox had quite a bit of oily residue inside, this was cleaned out with some cloths and petrol. The small breather hose to the sump had lots of black bits of gunk come out which couldnt have been helping things.
Since I didn't have the right tool to remove the fixings on the Idle Control Valve (ICV) pipework, I removed it and the other electrical valve its plumbed into and rinsed through with carb cleaner/petrol. A little dirt came out so I think it was worth doing. I had previously been squirting a lot of carb cleaner down the top hose so perhaps that had already cleaned it a bit.
When replacing the throttle actuator switch the screws seem a little soft so pick a good screwdriver and take your time. When replacing the new one remember to remove the green O ring as the new one comes with it already in the switch recess. Make sure the spindle is pushed home firmly. In comparision the switch that came off rotated much more loosely than the new part, it makes me wonder if the other similar switch on the front of the throttle bar could also be wearing. At 38k miles it may need preventative maintainance.
Removing/Installing the special airbox metal clips:
To remove the clips use chanel lock pliers in a wide setting and pinch the clip using the bits that stick up. You are looking to unhook the outer part of the band from the inner bit, it should ping open and hopefully wont fall down
http://zo-d.com/stuff/images/channel-lock-pliers-s.jpg[img]
First prepare some choice swear words.... lightly grease the rubber pipes which will help seat the airbox on the engine over the lip (if you look inside there is a locating lip which you want to slip into place without snagging. I used a light smear of grease.
With the clips in the starting position (~1cm back from locked, the tab will rest in the notch and be loose on the rubber pipes) rotate the clip around until you can get a the pliers onto the clip and with firm and slow pressure, gently pinch together until the clip snaps into place. Its really easy with those pliars (needlenose ones didnt have the purchase or force to make it easy) however the 4th and 5th one from the front can be tricky, turning the pliars around helped as did accessing from the gap between the metal fuel rail.
I will try and take some photos of the spare clips I bought to show the removal and fastening pliar positions (never needed them but worth buying a few to play with beforehand).
I have replaced the offending item and had a very brief test drive - the dead spot on the first inch of throttle travel has gone, its now immediate to rev up and feels very perky. 8) :evil:
When the revs fall it no longer undershoots and its idling a little bit higher too - solid idle.
This has made is so much nicer to pull away without sputtering and bogging down.
Points to note:
The the technical instructions some the live electrical feed does not seem to fit to the plenum (unless its one of the main wires at the back which unhook without any fuss.
When you think everything has been undone and want to remove the air take box you will probably find a vent to the sump is still connected at the back underside of the airbox - now this won't come off the airbox like it suggests but instead get a helper to lift the box up and with a torch follow it down to the sump. Squeeze in the clip (similar to the retentions used on the breather pipes up top) and remove at the lower end - easy
My thottle butterflies were quite dirty and there was a hard residue along the lower edge of the butterfly. I cleaned them the best I could using a lint free cloth and a sturdy toothbrush and a can on Wynns carburettor cleaner. To open the butterflies and clean the back of them and inside where they shut pull the actuator rod down and then wedge a piece of wood near the top.
The airbox had quite a bit of oily residue inside, this was cleaned out with some cloths and petrol. The small breather hose to the sump had lots of black bits of gunk come out which couldnt have been helping things.
Since I didn't have the right tool to remove the fixings on the Idle Control Valve (ICV) pipework, I removed it and the other electrical valve its plumbed into and rinsed through with carb cleaner/petrol. A little dirt came out so I think it was worth doing. I had previously been squirting a lot of carb cleaner down the top hose so perhaps that had already cleaned it a bit.
When replacing the throttle actuator switch the screws seem a little soft so pick a good screwdriver and take your time. When replacing the new one remember to remove the green O ring as the new one comes with it already in the switch recess. Make sure the spindle is pushed home firmly. In comparision the switch that came off rotated much more loosely than the new part, it makes me wonder if the other similar switch on the front of the throttle bar could also be wearing. At 38k miles it may need preventative maintainance.
Removing/Installing the special airbox metal clips:
To remove the clips use chanel lock pliers in a wide setting and pinch the clip using the bits that stick up. You are looking to unhook the outer part of the band from the inner bit, it should ping open and hopefully wont fall down
http://zo-d.com/stuff/images/channel-lock-pliers-s.jpg[img]
First prepare some choice swear words.... lightly grease the rubber pipes which will help seat the airbox on the engine over the lip (if you look inside there is a locating lip which you want to slip into place without snagging. I used a light smear of grease.
With the clips in the starting position (~1cm back from locked, the tab will rest in the notch and be loose on the rubber pipes) rotate the clip around until you can get a the pliers onto the clip and with firm and slow pressure, gently pinch together until the clip snaps into place. Its really easy with those pliars (needlenose ones didnt have the purchase or force to make it easy) however the 4th and 5th one from the front can be tricky, turning the pliars around helped as did accessing from the gap between the metal fuel rail.
I will try and take some photos of the spare clips I bought to show the removal and fastening pliar positions (never needed them but worth buying a few to play with beforehand).