Number 5 cylinder data graph???

[Naylz]

Got this on my code reader, all the other cylinders seem to give figures nicely within the -200 to 200 range, but number 5 cylinder is doing this.?? So I tried swapping the coil from number six cylinder but the graph stayed the same for number 5. So this rules out the coils, stupidly I didn’t think to swap plugs to see if that made a difference. So I will try that tomorrow not unless anyone on here knows of any other reason why this is happening.

 

[Naylz]

Oh just realised I took a photo of the plug from number 5 cylinder (was checking the part number) am I right in thinking that gap is a bit big?

 

[buzyg]

Does look rather wide. :?

Have a read here...

https://z4-forum.com/forum/viewtopic.php?t=83158

 

[wonkydonkey]

Comparing and swapping spark plugs tomorrow should shine some light on proceedings

 

[Naylz]

Yes seems you could drive a bus through that gap, will try swapping plugs tomorrow

 

[Naylz]

Update: tried swapping the plugs about today, another dumb question are the cylinders numbered from the front of the vehicle, 1 being front and 6 being nearest steering wheel? Or the other way around?? Any way I swapped what I thought was 5 with 2, tried just the coil part swapped= no change then just the plugs= no change and then both= no change. So I'm now at a loss?? I was guessing the reader graph of -200 to 200 was somekind of performance reading of that plug/coil and now I'm not so sure? As the vehicle is new to me I am going to renew the plugs anyway and see if that changes anything. My idle is a little bit bobbly although my reader says the idle should be 700rpm and the (idle) graph in fairness doesn't deviate too much, maybe +/- 20rpm at most. Am I just being paranoid for no reason? Ah well, I'm off to crawl underneath it now to try and locate anything loose, it does sound like bits are trying to fall off when going over bumpy road surfaces (ps my other vehicle is a Landrover defender and bits literally do detach from that )

 

[Lance]

1 is at the front, 6 near the screen.

 

[Naylz]

Having spent most f the day beneath my Z4 I have found, 1x heat shield bracket broken ( now fixed), rear drivers side bumper corner only held in position by the wheel arch liner ( previous owner must have had a bump and not fixed it, now fixed) and I noticed a tiny bit of play in the driveshaft passenger side where it comes out of the rear diff, (not sure if that's normal, going to drop diff oil and renew and see what's in the old oil)...oh and the MOT advisory of excessively deteriorated anti roll bar dust cover ( was the top end of the tie rod, new ones ordered), also removed the rubber drain plug things from the rear wheel arches, both were very blocked with crud, amazing really as the roof motor was renewed and repositioned into the boot by the dealer before I bought it so why they didn't unblock the drains is beyond me.

Yes I'm getting the bug for Z4's

 

[propaintballa]

Weirdly I have this too, I posted about it a few months back in my thread you've posted in before. For some reason the pictures aren't working, but this is the post.

Okay so quick update, if this counts as one, other than my bloody sunroof now randomly opening, I have stumbled upon a new bit of info from my OBD reader.

Within the "smooth running" live data, cylinder 5 appears to be running waaayyyyy out of the parameters listed (-200 to 200). -200 to 200 what exactly, I am not sure, but the values seemed to peak at ~-3000 (picture below). The rest seem to be around (-)50, +-50 or so.

Seeing as I have replaced coils and plugs within the last couple of months, my thoughts are now with the injector. Of course it could still be anything, could be valve or cylinder related, however I find the latter options highly unlikely... Any thoughts on the likelihood of an injector problem? When I have time, I could try swapping injector positions and see if the rough running follows.

The only problem I have with this diagnosis is that I have listened to the injectors for the solenoid function and they all seem the same to activate consistently and with the same volume. I have Also tried injector cleaner since I've had this problem which hasn't done anything (surprise).

I'm not sure what to make of this. I guess the only other component to swap would be an injector and see if the reading follows after that. The only other thing to note was that I also looked at rough running data via INPA but I didn't see the same reading on there as on my OBD reader.

 

[Naylz]

So I'm not alone Basically I have driven probably 900 miles since posting this, the only codes I get recurring are knock sensors 1 and 2. I've renewed plugs, swapped coils, renewed vanos solenoids (thought mine may have been originals), checked disa works as it should, new air filter. My Z4 drives great now I'm used to it, just a bit lumpy at low revs and speed but nothing too dramatic. I do average motorway miles and I'm getting 29.4mpg which I'm guessing is reasonable for the car. So I guess I'm kind of accepting it and not getting as paranoid, especially after a work colleague asked if he could borrow my code reader for his much newer regularly serviced one series 1.8d and it had two pages of fault codes and drove ok.

 

[Ewazix]

Basics are obviously fuel, spark and compression, you have looked at the first two so I'd compression test all cylinders to make sure No 5 isn't down. It might be worth running a quality injector cleaner through the system and whipping out the plugs after a good run to compare the colour and deposits. Since your knock sensors are also showing codes maybe try a tank of Tesco 99 or Vpower etc. After that I'd be thinking injector as you mentioned.

 

[propaintballa]

So I just explored this some more. Obviously take these results with a pinch of salt being that we obviously have different cars, the difference is that I have cause to believe there is something wrong with mine. For those who don't know I have a rough idle and hesitation/stuttering at low RPM.

So I just took the injectors out to inspect them, all looked fine. checked the wiring harness and couldn't see anything obvious. Left the fuel rail pressurised whilst they were out to see if any were leaky, all seemed good there. Checked resistance of all of them and they were all within ~.3 ohms or so of each other. Swapped my injector 5 with injector 1 to see whether this weird rough running followed and it stayed with cylinder 5.

I guess you can probably rule out any injector issues too at this point!

 

[Ewazix]

Weird thing if you google misfire on No5 on these engines, there are loads of reports! Apart from several being coils, very few seem to get resolved easily but some have solved it by replacing the Camshaft Position Sensor on the Intake side. Worth doing some more research