Z4 Coupe - Sudden Misfire - Q. about coils

T

TameRacingDriver

Member
 Newcastle Upon Tyne
Hi all,

I was driving back the other day, and I put my foot down a little - not WOT or anything, and suddenly the car seemed to be misfiring and was seriously down on power, engine light came on.

Limped her home, and stopped the engine and restarted. Was back to normal.

So I've been doing lots of reading and it would seem like a likely cause is a dodgy coil.

I'm currently waiting for my OBD reader to arrive I bought from ebay to see what error codes may have been thrown up.

In the meantime, I've been looking at ECP and when I put my reg no in I am offered a choice of 3 different Bosch coils; I am wondering which one to get as I've been reading that some coils that some members have tried to fit have not fitted correctly The three options listed below:-

http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110187&1&4a10021abf02a695f1dab9bd91ee37c4af7f0d65&000197
http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110227&1&152bd1f7c94f6519ecd6d6f36aa85d5274c14285&000197
http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110237&1&9b7d5e328686459aa6cd243a90d387aad3927cb0&000197

So, IF I have to replace one or more coils, which is it I should be buying?

Also, is it best just to fix the faulty one or replace them all - when I've read some say they'll only replace the faulty one but others say you may as well replace them all since when one is gone, the others aren't too far behind?

The Sparks were replaced 20K miles ago, should these be OK?

I'm no mechanic but I'm not totally alien to getting my hands dirty, so will I need any special tools to fit these?

Thanks for any help you can give :)
 
No special tools needed just push in pull out. Find which one is not working by lifting the hinged lock at the top. When you do this you will lose that cylinder so when the engine noise doesn't change that's the one you need to replace. :thumbsup:
 
TameRacingDriver said:
Hi all,

I was driving back the other day, and I put my foot down a little - not WOT or anything, and suddenly the car seemed to be misfiring and was seriously down on power, engine light came on.

Limped her home, and stopped the engine and restarted. Was back to normal.

So I've been doing lots of reading and it would seem like a likely cause is a dodgy coil.

I'm currently waiting for my OBD reader to arrive I bought from ebay to see what error codes may have been thrown up.

In the meantime, I've been looking at ECP and when I put my reg no in I am offered a choice of 3 different Bosch coils; I am wondering which one to get as I've been reading that some coils that some members have tried to fit have not fitted correctly The three options listed below:-

http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110187&1&4a10021abf02a695f1dab9bd91ee37c4af7f0d65&000197
http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110227&1&152bd1f7c94f6519ecd6d6f36aa85d5274c14285&000197
http://www.eurocarparts.com/ecp/c/BMW_Z4+Coupe_3.0_2007/p/car-parts/ignition1/engine-parts/ignition-coil/?413110237&1&9b7d5e328686459aa6cd243a90d387aad3927cb0&000197

So, IF I have to replace one or more coils, which is it I should be buying?

Also, is it best just to fix the faulty one or replace them all - when I've read some say they'll only replace the faulty one but others say you may as well replace them all since when one is gone, the others aren't too far behind?

The Sparks were replaced 20K miles ago, should these be OK?

I'm no mechanic but I'm not totally alien to getting my hands dirty, so will I need any special tools to fit these?

Thanks for any help you can give :)
Click to expand...


Sorry the first coil is the one you want.
 
Cheers, handy to know - however I think at this stage the problem is intermittent (it happened for the first time the last time I drove it, and I've not driven it since) so it might not happen when I'm troubleshooting, so hopefully the OBD+Torque can point me in the right direction.

Thanks for pointing out the correct coil :)

I'll upload whatever I find from torque on here if I'm not sure (quite likely haha).
 
i would only replace the duff one, the others could go on for years with no issues just as easily as a new one could fail after a few months...
Its one of lifes imponderable quandries.
regards
 
Cheers Smartbear - I am a bit skint at the moment, so I'll just try finding and replacing the duff one, if thats what it is. I've just received my BT OBD reader off the 'bay so I can give it a go later or tomorrow when I have more time.
 
So I hooked up the OBD reader to the torque app, and it threw up the following codes:-

Current Fault - P1553 - Powertrain

Pending Fault - P0301 - Cylinder 1 Misfire Detected

A quick search seems to suggest the VANOS Solenoid, which can be cleaned, but ideally replaced? And I'm wondering, would that potentially cause the misfire in Cylinder 1?
 
Today I've took the solenoids out and cleaned them with electrical contact cleaner, let them dry, and swapped coil cylinder 1 with 2. Took it for a good workout and got back, no error codes as yet. Will keep an eye on it. Thanks to those who helped :)
 
Thanks for reporting back having done the work - Good to know what resolves these sort of issues! :)
 
The problem has re-occurred, so I am guessing that whatever I did was either temporary or it was just pure luck / coincidence that it happened again.

I first noticed something was up when I was accelerating in 4th, and got a very noticeable and sudden flat-spot / hesitation at about 3,000 rpm. My girlfriend didn't notice anything being wrong, but I mentioned that I thought something was up.

So I tried to replicate it to show her, and after a couple of times, engine light came on and car was lumpy and down on power. I turned the engine off and back on which got rid of the engine light and I was able to drive home slowly, with no further issues.

When I got back, I plugged the OBD reader in again but this time I got NO ERROR CODES. :roll:

Now again, this may be coincidence, but I accidentally left the OBD reader plugged into the car overnight. The next day when I tried to start the car, it wouldn't start first time (almost as if the battery was flat). Luckily it started second time and so I took it for a good run - again no issues, but I didn't give it full throttle or anything (though I did let the revs get up to about 6000).

With no error codes to go on, I'm a little stumped. Anyone got any ideas? Otherwise, I'm sure the issue will be back and this time I've got everything at the ready to plug in when it does. I'll keep the thread updated.
 
I had the symptoms you describe recently and the same issue with the intermittent fault code despite emissions light. I can 90% guarantee its the coil in cylinder 1. The fault will get logged again eventually, then just swap the coil. The trick to making it appear is high gear low revs heavy throttle, that way you put the engine under heavy load which draws out the fault in ignition.
 
Hi Jimbob. Thanks for your post. It does seem to happen the way you describe. As it happens, I've now got a new coil from ECP, so I'm just waiting to see which cylinder it is :)

I thought about changing the spark plugs too since they're only a tenner a pop.
 
Just wanted to report back that it looks like Jimbob, you were bang on the money with your theory!

I'd originally swapped cylinder 1 and 2, but ultimately, although I was unable to get any error codes, the car definitely wasn't running 100%, with very noticeable hesitation in the acceleration.

So, I thought I'll just give this new coil a try, so swapped the one from cylinder 2 (originally in #1) with the brand new one, and I've just come back from an 80 mile drive (wasn't meant to be THAT long), the car has a new lease of life, smoother, quicker and no hesitation any more.

:thumbsup: Cheers Jimbob, was a good shout that!
 
You must log in or register to reply here.
Back
Top Bottom