Misfiring/Juddering/Lurching Under Acceleration

[Snoop D]

Hi again,

So following on from my previous thread( https://z4-forum.com/forum/viewtopic.php?f=2&t=117868 ), I now have ANOTHER problem

Some quick background info:

2003 Z4 3.0i SMG
Car was last properly driven in November 2014 - has been stored off road on my drive since, but I did however move it out this summer and it drove fine...
Tickety/Tapping noise as described in my previous thread has now quietened down after I did an oil change last week.
Yesterday I added 50/50 coolant/de-ionised water mix to radiator reservoir tank until full. Oil level was fine too.
Had to add fuel with one of those green carry containers as it had no fuel in it since (got around £7.50 worth of fuel in)

Planned on taking the car out for a long drive yesterday as suggested by many members on here just to get the new oil fully circulated. Fuel light was on again but above the last marker so I decided to go to the nearest petrol station. On the way, I noticed the car started juddering/misfiring and was feeling hesitant to pull away under light acceleration. Engine light and EML light came on. I tried putting it in sport mode just to see if it'd make any difference, no change. I turned back home and it progressively got worse. Parked up in my drive and it cut out itself. I started it up again and it was idling rough like as if it's running on only 2 cylinders lol. Revs were very lightly going up and down at idle.

I'm thinking it may be poor fuel or spark plug/ignition coil related. I'll first try adding more fuel (I'll give Shell V-Power a shot this time). If that fails I'll get a code reader and check the coilpacks/sparkplugs and try switching them over.

Does anyone else have any experience on this? And is there a definitive way of checking fouled ignition coils (i.e. with a multimeter?)

It's strange that this happened all of a sudden and the engine lights came on. It was all fine then about 5-10 mins into a drive it started running like a bag of s**t.

Any help would be greatly appreciated!

 

[Jl-c]

May be water in the fuel that will have been at the bottom of the tank, sucked through and now it's trying to run on it! If you can remove the fuel line from the end of the rail and run the fuel pump and collect it in a jar for a look see?

 

[Snoop D]

May be water in the fuel that will have been at the bottom of the tank, sucked through and now it's trying to run on it! If you can remove the fuel line from the end of the rail and run the fuel pump and collect it in a jar for a look see?

Thanks for your reply. This could be possible as I did remove the oil filler cap yesterday and noticed some mayo/yellow gunk on the cap, i.e. water condensation in the oil. So it may possibly be in the fuel tank too. Anyone know which fuel line I should be removing to check? (pic will be helpful).

Before I go ahead and add fuel in, can I get away with adding as much fuel in (diluting the water condensation) or should I not start it again?

Thanks again.

 

[Jl-c]

Hose you need to remove. Car cold obviously as you may spray fuel about. If you are not totally happy doing this I suggest you get a mechanic in!

 

[Snoop D]

So I just put Shell V-Power in, just less than half showing on the fuel gauge and started it up and idled for 5 mins. Still sounds and runs like a bag of s**t, misfiring and revs unstable around 800-1200rpm.

Is there an easy/definite way of checking for a bad coilpack (i.e. measuring with a multimeter?). I'm going to take them out, swap them over to another cylinder and see if there's any change.

Thanks!

 

[skelters]

Have you had a diagnostics done on the car at all?

If you did then what error codes did it throw up?

If not you need to get a diagnostics check done. There'll be someone near with Carly probably.

Check on the Carly thread.

What's the mileage and when were the plugs last changed?

It does sound like a Coil Pack issue but best to get a diagnostic done in case there are any other issues. Maybe order one Coil Pack and try changing to the new one on each cylinder.

 

[ph001]

Change out the coil packs for sure. Forget everything else until you have done thus.

 

[Snoop D]

Have you had a diagnostics done on the car at all?

If you did then what error codes did it throw up?

If not you need to get a diagnostics check done. There'll be someone near with Carly probably.

Check on the Carly thread.

What's the mileage and when were the plugs last changed?

It does sound like a Coil Pack issue but best to get a diagnostic done in case there are any other issues. Maybe order one Coil Pack and try changing to the new one on each cylinder.

Hi, thanks for your message. Unfortunately I don't have my scan tool with me at the moment (left it at my friends garage a few weeks back) so I'm unable to post fault codes on here. Mileage is 102k, I bought the car in 2014 with 98k so don't know when the plugs were changed. I did remove them today however, they looked OK-ish, they were BMW R3 Bosch branded. They weren't heavily sooted, most of them were grey-ish in colour from the tip (tiny tiny white deposits) - hard to explain, I'll try get some pics up tomorrow. I'll clean them all with brake cleaner and wire brush and put them back in.

I totally agree, its very ambiguous at this stage with no code reader and fault codes at hand. I'll need to get my scan tool back and see what codes I get...

Cheers!

 

[Snoop D]

Change out the coil packs for sure. Forget everything else until you have done thus.

Hi there, I had the car started and pulled the connection for each of the ignition coils one at a time. Each one I pulled out, the idle would change sound. So this would suggest that all the coil packs are working fine? I also tested each coilpack with a multimeter. I connected the probes to left and right pins (ignored the top pin on the coil) and got a reading of 0.00 ohms. If there was a fault with the coilpacks the reading would show 1 (infinite resistance) or a very low resistance value?

So I ruled out the coilpacks and checked the spark plugs. I'm not too sure on these (I'll post pics of them) but I'll clean them with brake cleaner and wire brush before putting them back in. I also removed the fuel pump fuses and carried out a compression test, first time cranking the engine over I got just under 120psi straight away on cylinder 1. I tried it the second time but it would take A LOT of cranks to build up a pressure reading? Highest reading I managed to get was 90psi - I could have kept cranking it for longer and it may have went to 120psi again.
Anyways, moved to cylinder 2. Turned the key to ignition then tried cranking the engine over again. NOTHING. It wouldn't crank over now, turn the key and nothing happens - I can only hear a little relay like sound, that's it. I checked the ignition starter fuses and they were fine.
I'm suspecting the battery is low after cranking the engine over repeatedly. The Bosch battery is brand new, just bought it last week and had it on charge before installing, all the interior lights and windows and instrument cluster work fine though. Measured the voltage at the battery terminals and I was getting around 12.20V. Is this enough to crank the car?

Its one thing after the other and it beginning to piss me off now! :headbang:

 

[ph001]

I would expect 12.2V to be enough to crank the car but it’s nowhere near fully charged (that would be around 12.6V). Don’t forget that cranking the engine draws around 200A so that would flatten a fully charged battery in around 20 minutes. Also bear in mind that the starter motor is not designed to be run continuously as it gets very hot. I wouldn’t be cranking it for more than 30secs without a few minutes rest in between for it to cool down.

So first thing to do is get a charger back on it over night and try again next day. If it still doesn’t fire it could de a sticking starter solenoid (lay a piece of 2x2 wood on it and tap it with a mallet), a faulty ignition switch, or a burnt out coil on the starter

Back to your misfire problem...the coil packs can get moisture inside then which causes them to break down at high voltage so I’m not sure you can conclude anything by measuring them with a meter.

As said above, you are stabbing in the dark a little until you pull those codes and as the car has been stood for 5 years it could be many things, but I’d certainly be starting with coil packs.

Other commonish issues with M54 is a split intake hose or knackered DISA valve. The fact that it was left for so long without exercise does worry me a little...just hope that the mayo you are seeing in the oil hasn’t gunked up a feed anywhere and caused engine damage, so I can see why you wanted to check compression, although I still think that’s fairly unlikely

 

[AveZ4coop]

TBH if you cannot scan the codes, if I were you I would change plugs and coils now. A full set is less than £150 and will probably cure the problem. It is very easy to spend a lot more money than this on a battery, a starter, etc.... ,and if it is a coil or plug you will still have to pay the money anyway. Your symptoms sound like a coil pack is failing, and if one is, the others will not be far behind.

I hope you get it sorted soon.

 

[AC5L4T3R]

Had this happen on my old Astra 10 odd years ago, replaced the coilpack and the problem went away.

 

[Snoop D]

OK, so a little update...

Still waiting on my friend to bring my scan tool back! But had a further look at the problems again.

Regarding the non-start/crank issue I reported earlier - which just came out of the blue (all electrics working - lights, windows, radio, wiper etc, but nothing on the third turn of the key, just a little quiet click noise). I had a search around on this forum and tried the famous 'hammer tap' technique. Hit the top and side of the starter motor with a wooden block and hammer. Battery at 12.2V. It cranked over this time! lol. (Didn't start obviously as I had pulled the fuel pump fuses out as I was doing a compression test earlier...)

Finished completing the compression test as it's good to know anyways. Got around 110-120psi on all six. So can rule this out now.

Removed spark plugs and got photos of them as promised earlier. Gave them a good clean with brass wire brush and brake cleaner - came out okayish.

Pics of each spark plug below:

Spark plug 1:





Spark Plug 2:





Spark Plug 3:




Spark Plug 4:




Spark Plug 5:

 

[Snoop D]

Spark Plug 6:





I then cleaned all the spark plugs. They all looked more or less like this...





Re-installed them and tightened down to correct torque spec and connected all the coilpacks back up.

Went to start the car now, but nothing happened again - no cranking. Battery was reading 12.2V but I attached a jump starter pack to it anyways just in case. Gave the starter motor LOTS of hard taps with a hammer, wooden block and prybar at many different angles, tried it again with someone in the car cranking it over while I tap the motor, but it just wouldn't turn over again! It did change noise a few times - struggling to start - so it must be a faulty starter motor now. Can these be removed and cleaned out with isopropyl alcohol/electrical cleaner? Or is a brand new one my only option? If so, wheres the best place to buy from? Also, is there a How-To guide for the starter motor? As I'm hopeless at using forum search tools.

It's obvious now that this is first priority as I can't start the car now to check if the misfire has changed...

All help is greatly appreciated!

Thanks again!

 

[lucasxdiniz]

Went to start the car now, but nothing happened again - no cranking. Battery was reading 12.2V but I attached a jump starter pack to it anyways just in case. Gave the starter motor LOTS of hard taps with a hammer, wooden block and prybar at many different angles, tried it again with someone in the car cranking it over while I tap the motor, but it just wouldn't turn over again! It did change noise a few times - struggling to start - so it must be a faulty starter motor now. Can these be removed and cleaned out with isopropyl alcohol/electrical cleaner? Or is a brand new one my only option? If so, wheres the best place to buy from? Also, is there a How-To guide for the starter motor? As I'm hopeless at using forum search tools.

I wrote this how to on how to change the starter motor on the N52 engine, I am sure it's going to be pretty much the same process on the M54.

https://z4-forum.com/forum/viewtopic.php?f=34&t=116463

Although the electrodes in your spark plugs look alright, the amount of filth on them surprised me. I would personally change the plugs & coil packs as preventive maintenance (which will also cure your mis-firing I bet).

 

[Jl-c]

" Although the electrodes in your spark plugs look alright, the amount of filth on them surprised me. I would personally change the plugs & coil packs as preventive maintenance (which will also cure your mis-firing I bet). "

I agree, I would throw those plugs and replace them, they aren't expensive after all.