Cylinder 5 misfire problem & troubleshooting

Y

Yamiuchi

Member
 Colchester, Essex
Hi All, happy new year,

Got an intermittent problem since I have had the car a few years now (3.0i 2003) with cylinder 5 causing a misfire. I have replaced all of the coil packs & spark plugs on the car at least twice, and I am now pretty sure its not a coil pack/spark plug problem.

I got the misfire recently so swapped coil pack 5 with coil pack 6 and still getting the misfire on cylinder 5.

Symptoms are the misfire, engine management light comes on. Switch engine off and restart misfire usually goes away and car runs ok, after a few trips engine management light goes off and the normal misfire code is left in ecu.

At the end of journeys sometimes when i have switched the car off go to get out and the car beeps at me 5 times which i can only assume is something to do with cylinder 5 misfire. I have lived with it until now but need to get it sorted as getting fed up with it.

I have been browsing the web and I now need to troubleshoot this cause as the colder weather is causing the issue to happen a bit more, so in doing some reading people are saying to look at:

fuel filter
fuel pump
fuel injector
MAF sensor
Cam Sensor

had the fuel filter changed since having the car and misfire was there already so doubt its that one.

this link seems interesting http://www.bimmerfest.com/forums/showthread.php?t=500419

couple of other bits:

Also been told by an indy that a clunk noise from the rear diff looks like it needs replacing. I have already done the grease fix on the forum with no effect. :headbang:


any help appreciated.
 
Had it checked by 2 different mechanics and its always cylinder 5 that has the misfire, I'm that confident that I have all the tools to take off the cover and a spare coil pack in the boot in case the problem creeps up and restarting doesn't fix it, replace number 5 and away we go.
 
When we are talking about M54 first thing to check is vacuum leaks.
First do that smoke vacuum test. Many garages have this kind of equipment and it is not expensive test.

https://www.youtube.com/watch?v=FfiQ7qWiG-M



In fact M54 coil problems are not common. Vacuum leaks are. Engine shuts down that cylinder which runs incorrectly and usually fault code will be misfire. I would bet that problem is not spark plug or coil. If the problem is coil pack it is easy to diagnose just swap two coil packs like cylinder 5 and cylinder 1, if fault moves to cylinder 1 then replace coil pack.
 
check spark plugs, then injectors and do a completion test on cylinder 5 this should show up the problem, my guess injector.
 
thanks for ideas, will give them a go, I was thinking injector possibly also.

will let you know how i get on. :thumbsup:
 
i have a set of injectors lying around somewhere as i have uprated ones for the supercharger. if you need any.
 
Ooooo Cool, what you looking for for those injectors please?

Is it an easy install for new injectors or is it a exhaust manifold off job?

tried looking around on-line and couldn't see a guide or pics anywhere. Going to get hold of a wiring loom as well to eliminate that problem in case its that.

The z4 will be back to its former glory!
 
Ive never seen injector fail on one of these engines..

More common is an HVA sticking.

Does it usually occur from cold start?
 
The misfire does seem more likely to happen when its been cold /damp but in the past I have done a 40 min journey stopped to get some petrol and then its started misfiring again , on a lovely sunny day :x

what is the HVA?
 
Ok update on original post:

Have replaced all fuel injectors, too soon to see if misfire is still happening.

But noticeable difference straight away is acceleration seems a lot smoother, and sitting at idle the needle jumped around a little bit, doesn't do that anymore.

On other side, have sourced a replacement rear diff, will get that fitted in a couple of months.

Just replaced runflats with standards. Whoa what a difference!
 
How do you guys pull the coil out? I've tried a couple of times on a 2.5si and it's so hard I could not pull 4 out of 6.
 
Yamiuchi said:
Ok update on original post:

Have replaced all fuel injectors, too soon to see if misfire is still happening.

But noticeable difference straight away is acceleration seems a lot smoother, and sitting at idle the needle jumped around a little bit, doesn't do that anymore.

On other side, have sourced a replacement rear diff, will get that fitted in a couple of months.

Just replaced runflats with standards. Whoa what a difference!
Click to expand...
Taken a while, but it sounds like your getting there. Fingers crossed, enjoy :driving: :thumbsup:
 
buzyg said:
Yamiuchi said:
Ok update on original post:

Have replaced all fuel injectors, too soon to see if misfire is still happening.

But noticeable difference straight away is acceleration seems a lot smoother, and sitting at idle the needle jumped around a little bit, doesn't do that anymore.

On other side, have sourced a replacement rear diff, will get that fitted in a couple of months.

Just replaced runflats with standards. Whoa what a difference!
Click to expand...
Taken a while, but it sounds like your getting there. Fingers crossed, enjoy :driving: :thumbsup:
Click to expand...
I don't think it did take a while, the poster above you revived a 3 year old thread
 
Nictrix said:
buzyg said:
Yamiuchi said:
Ok update on original post:

Have replaced all fuel injectors, too soon to see if misfire is still happening.

But noticeable difference straight away is acceleration seems a lot smoother, and sitting at idle the needle jumped around a little bit, doesn't do that anymore.

On other side, have sourced a replacement rear diff, will get that fitted in a couple of months.

Just replaced runflats with standards. Whoa what a difference!
Click to expand...
Taken a while, but it sounds like your getting there. Fingers crossed, enjoy :driving: :thumbsup:
Click to expand...
I don't think it did take a while, the poster above you revived a 3 year old thread
Click to expand...
:lol:
I blame the newbie. :) :thumbsup:
 
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