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N52 hesitation, stuttering, jerking, surging etc

Discuss problems you have had or are having with your Z4
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propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Thu Oct 25, 2018 9:53 am

ph001 wrote: Thu Oct 25, 2018 9:32 am
propaintballa wrote: Thu Oct 25, 2018 8:40 am Did you manage to look at my latest video and see how your lambda data respond to revving?
Yep - very similar. Not saying I understand why they don't swing around like they should, must be an INPA thing as I'm fairly certain they would with a scope on them.

Your batt volts look good so I think if the Valvetronic values check out OK you need to continue down the list:

1) Observe O2 sensor voltages in INPA
2) Fit new battery
3) Replace coil packs and plugs
4) Replace EGR valve and check pipes to sump for blockages
5) Replace / inspect second DISA valve
6) Replace valvetronic motor
7) Have VANOS unit stripped and inspected.
I think you might be right. So I checked the Valvetronic screen which looks pretty similar to yours, the only thing I noticed which looked odd was that my expected airmass (top right) was bouncing up and down by about 6 when at idle, but not when at 2000rpm. Have attached the screenshots :)
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ph001
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N52 hesitation, stuttering, jerking, surging etc

Post by ph001 » Thu Oct 25, 2018 10:39 am

Hmmm, yeh your calculated air mass is about 28% different to mine at idle. I'm really not too sure what that calculation represents though as the value is higher at idle than at 2000rpm so I think we can conclude a lower value is more air. We must remember that we are comparing a 3.0l car to a 2.5l one so I guess that makes sense then.

As you say, can't see anything else particularly unusual there, although mine wasn't bouncing around.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Thu Oct 25, 2018 11:00 am

ph001 wrote: Thu Oct 25, 2018 10:39 am Hmmm, yeh your calculated air mass is about 28% different to mine at idle. I'm really not too sure what that calculation represents though as the value is higher at idle than at 2000rpm so I think we can conclude a lower value is more air. We must remember that we are comparing a 3.0l car to a 2.5l one so I guess that makes sense then.

As you say, can't see anything else particularly unusual there, although mine wasn't bouncing around.
This makes sense. Would be extremely handy for the car to throw a relevant code! I might just have to bit the bullet and try new coils, which I think are most likely at this point. If not, then spark plugs and go from there. I don't want to do both at the same time as I would like to know what's actually causing the problem!

Do you know if it is possible to have a faulty coil that doesn't appear faulty when doing the "unplugging test"? As in, unplugging each coil one by one as the engine is running to see if the action of unplugging it changes the engine behaviour. As I have done this and the revs are affected for all of them.

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N52 hesitation, stuttering, jerking, surging etc

Post by ph001 » Thu Oct 25, 2018 11:58 am

propaintballa wrote: Thu Oct 25, 2018 11:00 am This makes sense. Would be extremely handy for the car to throw a relevant code! I might just have to bit the bullet and try new coils, which I think are most likely at this point. If not, then spark plugs and go from there. I don't want to do both at the same time as I would like to know what's actually causing the problem!

Do you know if it is possible to have a faulty coil that doesn't appear faulty when doing the "unplugging test"? As in, unplugging each coil one by one as the engine is running to see if the action of unplugging it changes the engine behaviour. As I have done this and the revs are affected for all of them.
Totally agree on doing the coils first. Aged / worn plug gaps manifest as a misfire at >50% load, typically at around the rpm where peak torque is made. It's very characteristic. You can also get them breaking down electrically around the ceramic of course which is a similar symptom to a dodgy coil pack. That's pretty rare though.

In terms of the coil unplugging test - that is really only effective if the coil pack is permanently faulty. More often than not they go intermittent at specific loads which gives the misfire / poor running.

BMW had no problem at all taking all 6 back from me when I was playing around with the M3. It's not like they get particularly dirty or marked when trying them and they just came in individual boxes which had a folded flap so the packaging was completely undamaged.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Thu Oct 25, 2018 12:04 pm

ph001 wrote: Thu Oct 25, 2018 11:58 am
propaintballa wrote: Thu Oct 25, 2018 11:00 am This makes sense. Would be extremely handy for the car to throw a relevant code! I might just have to bit the bullet and try new coils, which I think are most likely at this point. If not, then spark plugs and go from there. I don't want to do both at the same time as I would like to know what's actually causing the problem!

Do you know if it is possible to have a faulty coil that doesn't appear faulty when doing the "unplugging test"? As in, unplugging each coil one by one as the engine is running to see if the action of unplugging it changes the engine behaviour. As I have done this and the revs are affected for all of them.
Totally agree on doing the coils first. Aged / worn plug gaps manifest as a misfire at >50% load, typically at around the rpm where peak torque is made. It's very characteristic. You can also get them breaking down electrically around the ceramic of course which is a similar symptom to a dodgy coil pack. That's pretty rare though.

In terms of the coil unplugging test - that is really only effective if the coil pack is permanently faulty. More often than not they go intermittent at specific loads which gives the misfire / poor running.

BMW had no problem at all taking all 6 back from me when I was playing around with the M3. It's not like they get particularly dirty or marked when trying them and they just came in individual boxes which had a folded flap so the packaging was completely undamaged.
Great info, thank you so much for your help so far! I have ordered a new set of coils from OPIE. They only stocked Bosch, not the Delphi coils which I believe are supplied now, but for just under £100 for a full set, I can't complain too much. Will still check the price of them from BMW just in case they're similar, I doubt it though.

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N52 hesitation, stuttering, jerking, surging etc

Post by ph001 » Thu Oct 25, 2018 12:16 pm

propaintballa wrote: Thu Oct 25, 2018 12:04 pm Great info, thank you so much for your help so far! I have ordered a new set of coils from OPIE. They only stocked Bosch, not the Delphi coils which I believe are supplied now, but for just under £100 for a full set, I can't complain too much. Will still check the price of them from BMW just in case they're similar, I doubt it though.
That's a great price. Has to be worth it just to eliminate them from the equation. I'd like to think you could sell brand new Bosch coil packs on Ebay for £15 ech if it comes to that.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Thu Oct 25, 2018 1:34 pm

ph001 wrote: Thu Oct 25, 2018 12:16 pmThat's a great price. Has to be worth it just to eliminate them from the equation. I'd like to think you could sell brand new Bosch coil packs on Ebay for £15 ech if it comes to that.
I thought the same thing! Really hoping the coils are the issue. Have to wait a week or so for them to turn up though, which is less than ideal. I'll have to keep you updated as and when anything happens!

propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Mon Oct 29, 2018 7:03 pm

Right then! Some good news and some bad news... More good than bad though. So got my new coils today and got them installed this evening. I took the opportunity to inspect the plugs and make sure they were torqued correctly (I torqued to 25Nm). I have just taken the car out for a quick spin, will go for a longer drive this evening, but idle is a lot better and generally the car feels a lot smoother, especially at those troublesome RPMs. I do not feel the issue is completely remedied though, however, it could have something to do with the plugs and the story they may tell.

I have attached some pics of them, and to me (I am no expert on reading plugs) but they look oil fouled. Could this have something to do with the amount of oil I found in the intake manifold? Weird though as there doesn't really seem to be any sign of it burning oil. Regardless of the larger issue that might be present, it does look like a new set of plugs would likely be beneficial. When reinstalling, I cleaned off the threads as I didn't want to blast the plugs off and find they were the issue all along.

Anyone care to voice an opinion on this? Thanks all! Getting there!
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N52 hesitation, stuttering, jerking, surging etc

Post by Smartbear » Mon Oct 29, 2018 7:27 pm

Hi, I found when my si started to use oil it was fouling the plugs closest to the bulkhead the most which I presume is linked to the position the ccv is plumbed into the inlet manifold?
Rob
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e89 Sdrive 20i, plenty of mumbo & good economy-the thinking bears z4
e89 Sdrive 30i, this ones busted, pass me another...
e85 3.0si sold

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ph001
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N52 hesitation, stuttering, jerking, surging etc

Post by ph001 » Mon Oct 29, 2018 8:53 pm

Plugs don’t look good. I’d replace them and then sort your EGR valve issue asap.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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propaintballa
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N52 hesitation, stuttering, jerking, surging etc

Post by propaintballa » Mon Oct 29, 2018 9:17 pm

ph001 wrote: Mon Oct 29, 2018 8:53 pm Plugs don’t look good. I’d replace them and then sort your EGR valve issue asap.
Been looking for any info on EGR issues or even just the existence of it on this model and I can't find anything. Might it be more to do with CCV as mentioned below? Also wondering whether it could be a remnant from before I had the valve cover gasket changed.
Smartbear wrote: Mon Oct 29, 2018 7:27 pm Hi, I found when my si started to use oil it was fouling the plugs closest to the bulkhead the most which I presume is linked to the position the ccv is plumbed into the inlet manifold?
Rob
Oh right, was there an actual issue in the end? Blocked CCV or similar? I'll have to check my oil level to see if it is actually using oil.

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N52 hesitation, stuttering, jerking, surging etc

Post by Smartbear » Mon Oct 29, 2018 10:59 pm

propaintballa wrote: Mon Oct 29, 2018 9:17 pm
ph001 wrote: Mon Oct 29, 2018 8:53 pm Plugs don’t look good. I’d replace them and then sort your EGR valve issue asap.
Been looking for any info on EGR issues or even just the existence of it on this model and I can't find anything. Might it be more to do with CCV as mentioned below? Also wondering whether it could be a remnant from before I had the valve cover gasket changed.
Smartbear wrote: Mon Oct 29, 2018 7:27 pm Hi, I found when my si started to use oil it was fouling the plugs closest to the bulkhead the most which I presume is linked to the position the ccv is plumbed into the inlet manifold?
Rob
Oh right, was there an actual issue in the end? Blocked CCV or similar? I'll have to check my oil level to see if it is actually using oil.
I blamed a partially blocked ccv system as after flushing it through with sea foam several times matters improved to normal levels.
Rob
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e89 Sdrive 20i, plenty of mumbo & good economy-the thinking bears z4
e89 Sdrive 30i, this ones busted, pass me another...
e85 3.0si sold

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N52 hesitation, stuttering, jerking, surging etc

Post by ph001 » Tue Oct 30, 2018 8:19 am

Sorry for confusion...yes I meant CCV.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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N52 hesitation, stuttering, jerking, surging etc

Post by jack07 » Sat Nov 03, 2018 12:41 pm

Cost you nothing to remove and inspect the plugs.Distrust people who say they have been changed and have a look.Buy 2 coil packs and swap about if the plugs were ok.Good luck
:driving: :thumbsup: :) This is the car I've been waiting for http://s611.photobucket.com/user/markhorner100/albums

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N52 hesitation, stuttering, jerking, surging etc

Post by jack07 » Sat Nov 03, 2018 12:43 pm

Doh! Just seen plugs,sorry :(
:driving: :thumbsup: :) This is the car I've been waiting for http://s611.photobucket.com/user/markhorner100/albums

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