Z4-forum.com

Just your opinions please guys
my 35i has just started to missfire a bit and every few days it struggles to start , it normally fires first time but every so often it takes abut 5 or 6 seconds before it starts ?

thinking it could be a coil pack ,not sure just wanted some opinions from you guys

Cheers

for what its worth.......

likely to be injectors. if it 2-3 years old and sort of 25-30K miles

does it go something like this

injectors already?!?!

Check the forum. There are a few of us on here who have suffered simerly and it was the injectors .

My HPFP failed at 6k miles.

My rear demister (new rear screen) failed at 6k miles.

My 296 rears cracked at 8k miles.

My DCT replaced at 10k miles due to vibration (which returned at 30k miles and I just can’t be bothered with).

My exhaust replaced at 15k miles due to failed flap (which has failed again).

A rear spring snapped at 20 k miles

My water pump & injectors failed at 34k miles

My valve cover cracked (plastic) at 34.5k miles.

My PCV pipe split at same time as valve cover due to injector replacement.

... and that’s just what I remember.

Car still isn’t running right... still battling... most un reliable car ever owned.

So mine has set the bar, I’m sure some of these will crop up for others in due course.

Oh yes I forgot, also got a leaking adaptive front shocks to sort...

Maniac wrote: ↑Sun Jan 21, 2018 3:19 pm My HPFP failed at 6k miles.

My rear demister (new rear screen) failed at 6k miles.

My 296 rears cracked at 8k miles.

My DCT replaced at 10k miles.

My exhaust replaced at 15k miles.

A rear spring snapped at 20 k miles

My water pump & injectors failed at 34k miles

My valve cover cracked (plastic) at 34.5k miles.

My PCV pipe split at same time as valve cover due to injector replacement.

Car still isn’t running right... still battling... most un reliable car ever owned.

So mine has set the bar, I’m sure some of these will crop up for others in due course.

With all due respect, I hope you are a minority of 1.

I’d like to keep mine a while longer, but won’t own without insurance.

I too hope others fair better but there’s a lot of failures around the N54 over all models Z4/1/3/5/X etc

I’ve had pretty much every failure known now, just the roof to fail next... give it time.

flippin heckkkk

im going to stick to my e85 3.0i for now!

Maniac wrote: ↑Sun Jan 21, 2018 3:19 pm My HPFP failed at 6k miles.

My rear demister (new rear screen) failed at 6k miles.

My 296 rears cracked at 8k miles.

My DCT replaced at 10k miles due to vibration (which returned at 30k miles and I just can’t be bothered with).

My exhaust replaced at 15k miles due to failed flap (which has failed again).

A rear spring snapped at 20 k miles

My water pump & injectors failed at 34k miles

My valve cover cracked (plastic) at 34.5k miles.

My PCV pipe split at same time as valve cover due to injector replacement.

... and that’s just what I remember.

Car still isn’t running right... still battling... most un reliable car ever owned.

So mine has set the bar, I’m sure some of these will crop up for others in due course.

Oh yes I forgot, also got a leaking adaptive front shocks to sort...

I've recently created a a thread about a similar problem on my car..
viewtopic.php?f=45&t=102980&p=1503981#p1503981

what I've learnt is misfire can be caused by three things.

• Spark Plug

• Coil Pack

• Injector

They should be replaced in that order - cheapest to most expensive.

If you can identify which cylinder is problematic, the first thing to do is swap the spark plug and coil with another cylinder.
If the misfire moves to the new cylinder then its plug or coil that's faulty. £10 for a plug, £20 for a coil. Takes 10 mins to fit. Ideally you would replace all 6.
If the misfire is still on the same cylinder then the injector is faulty. A bit more expensive at £102 and it must be coded to the car.

I find the best way to read codes is probably the "C110 Code Reader"
I've also got the android app torque and a bluetooth OBDII reader, but it doesn't seem capable of clearing 'pending' fault codes. Which is a problem with misfires as they always seem to be logged as pending.
Carly for BMW is a very good app, but you need to purchase both the app and USB cable.

part number for replacements;
Spark plugs - BOSCH ZGR6STE2
Coil pack - Eldor 12138657273 or Delphi GN10571 (newer N55 engine uses this)
Injector - 13538648937 £102 from BMW direct. These cant be reconditioned/cleaned/rebuilt, so be wary of anything cheaper.

Further note on Injectors.
They have a revision, or 'index' number. The picture of mine below are index 7.
All new injectors are index 12.
Index 10 or lower cant be mixed with 11 or higher in the same bank. Banks are 1,2,3 and 4,5,6.
I have a misfire in bank 1, so I need to replace injectors in cylinder 1, 2 and 3. Ideally you would replace all 6.
After fitting the injector must be coded to the car - The factory tests each injector and stamps it with its exact flow rate, the car must be programmed with this so that it doesn't over/under fuel.
You can do this yourself with ISTA, or INPA - loads of guides on how to set these up so wont go into it here.



Hope that helps!

So i've changed the coil packs but got the wrong plugs as the right ones have like a torx fitting on them
but it is still the same missfire
but the start up seems to be fine now
the start up problem seemed to start when the service light came on also the parking sensors came up with a fault and since i have cleared the service warning they have sorted themselves out ??????? wtf do you think bmw code things like this to make you take the car to them so they can get more money from us also little things like odd spark plugs so we cant do maintenence on our cars
just a thought ???
and thanks for the replies i know it will be the injectors as there the most expensive lol

My misfire used to disappear for days, I’m sure it was relative to what cylinder valves were open.

Ie if the leak was on injector 1 and the engine came to rest with these valves open, then the extra leaked fuel would evaporate from the cylinder. If it came to rest with the same valves closed, then no evatoration / ventilation happened.

Finally when I convinced my dealer it was this sort of fault, they left the car for a day or two and pulled the injectors and found 2 with wet tips which evidenced fuel let by. Try it.