Engine misfire carly code P0302

sharpyboy · Post by **sharpyboy** » Mon Mar 23, 2020 1:43 pm

Hi Guys

As the title suggests i took my zed out to have a new tyre fitted and on the way back i noticed it running rough and a yellow engine warning light came on. I stopped and restarted the car and the engine warning light stayed off but the rough running continued so when i got home and plugged Carly in and it came up with a PO302 code which i think is misfire in cylinder 2. This could be spark plug/loose connection orignition coil so i wondered if there was any way to determine the exact item that needs looking at/replacing. Anybody else had this? is it common with zeds or BMW's? Any special tools needed to remove coil packs or spark plugs?

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Any advice welcome, something to do while i'm social isolating

Chris_D · Post by **Chris_D** » Mon Mar 23, 2020 2:16 pm

Swap a coilpack around and see if it makes any difference. If not, swap 2 plugs around. Process of elimination.
If that doesn't change the issue start checking condition of leads and other potential sources.
I'm banking on your plug being fouled. Check for sooty carbon deposit on head or oil on threads and head.

No special tools needed as the coils just pull out after flipping the tab up.
But make sure you use a plug tool with a fixed head, not just a ratchet and extension and head as the head will just pull off and get trapped in the plug tube when you try to pull out the plug. Don't ask me how I know this.

sharpyboy · Post by **sharpyboy** » Mon Mar 23, 2020 6:25 pm

Chris_D wrote: ↑Mon Mar 23, 2020 2:16 pm Swap a coilpack around and see if it makes any difference. If not, swap 2 plugs around. Process of elimination.
If that doesn't change the issue start checking condition of leads and other potential sources.
I'm banking on your plug being fouled. Check for sooty carbon deposit on head or oil on threads and head.

No special tools needed as the coils just pull out after flipping the tab up.
But make sure you use a plug tool with a fixed head, not just a ratchet and extension and head as the head will just pull off and get trapped in the plug tube when you try to pull out the plug. Don't ask me how I know this.

Thanks, I have just started the car up and it appears to be running OK, will do a test drive tomorrow and then check under the bonnet/hood for loose connections and do coil swap/ ug swap if needed, thanks Chris_D

sharpyboy · Post by **sharpyboy** » Tue Mar 24, 2020 5:34 pm

Well checked the car this afternoon and the misfire is back so cleared the codes in Carly and swapped the coil pack from 1 to 2, sprayed wd40 in the coil pack sockets and started the car to see if the fault moved with the coil position and all was clear, no fault again. So I will leave till tomorrow and see if the misfire is still fixed and take it for a run to check if the fault is back I'll check which cylinder it's on.

-Tom- · Post by **-Tom-** » Tue Mar 24, 2020 7:20 pm

Checked the plugs yet? I just lost my words when I pulled this out of my Mini Cooper S today (20k miles of use )

Believe it or not, that was for a misfire only under load with a temporary EML when it did so. P0302 code also up, although this was cylinder 1 and 2 was fine

sharpyboy · Post by **sharpyboy** » Wed Mar 25, 2020 12:51 am

-Tom- wrote: ↑Tue Mar 24, 2020 7:20 pm Checked the plugs yet? I just lost my words when I pulled this out of my Mini Cooper S today (20k miles of use )

Believe it or not, that was for a misfire only under load with a temporary EML when it did so. P0302 code also up, although this was cylinder 1 and 2 was fine

Wow that's a large plug gap

I haven't checked my plugs yet as I need one of those thin plug tools as the one I have from previous cars will not fit.

baconJazz · Post by **baconJazz** » Wed Mar 25, 2020 1:20 am

Exactly the same thing happened to me last week. Took it to BMW and a misfire was flagged up in cylinder 5. They did the coil swap for a migration test ,but still an issue with cylinder 5 . Changed all plugs at a cost of £187 and the car now drives better than it ever has in the 6 months I've owned it.. Job done.

noiseboy72 · Post by **noiseboy72** » Wed Mar 25, 2020 10:06 pm

I had this the other day - It went down to 5 cylinders and ran as rough as a fat lass from Ormskirk.

I put the scanner on it and it came up with Misfire Cylinder 5. Plugs are only 10 months old and it's only done 12K on them, so I'm fairly certain they are fine.

Reset and erased the fault and it's been fine since, but I will be keeping an eye.

Ewazix · Post by **Ewazix** » Thu Mar 26, 2020 5:57 pm

-Tom- wrote: ↑Tue Mar 24, 2020 7:20 pm Checked the plugs yet? I just lost my words when I pulled this out of my Mini Cooper S today (20k miles of use )

Believe it or not, that was for a misfire only under load with a temporary EML when it did so. P0302 code also up, although this was cylinder 1 and 2 was fine

Hi Tom, you need to watch that on the Cooper S, drastic plug burning is a common problem and can indicate some serious engine damage is in progress. Best case is the plug being the wrong grade, otherwise it's a lean burn /pre-ignition problem caused by a faulty injector or possibly the common coking problem (hot coke deposits in the burn chamber pre-ignite the charge) either can overheat the cylinder, piston crown and valve seats causing potentially expensive damage. You may be hearing 'pinking' under load? My old S had the issue and was repaired under warranty catching it in time before a big re-build was required.

-Tom- · Post by **-Tom-** » Thu Mar 26, 2020 6:04 pm

Ewazix wrote: ↑Thu Mar 26, 2020 5:57 pm
-Tom- wrote: ↑Tue Mar 24, 2020 7:20 pm Checked the plugs yet? I just lost my words when I pulled this out of my Mini Cooper S today (20k miles of use )

Believe it or not, that was for a misfire only under load with a temporary EML when it did so. P0302 code also up, although this was cylinder 1 and 2 was fine
Hi Tom, you need to watch that on the Cooper S, drastic plug burning is a common problem and can indicate some serious engine damage is in progress. Best case is the plug being the wrong grade, otherwise it's a lean burn /pre-ignition problem caused by a faulty injector or possibly the common coking problem (hot coke deposits in the burn chamber pre-ignite the charge) either can overheat the cylinder, piston crown and valve seats causing potentially expensive damage. You may be hearing 'pinking' under load? My old S had the issue and was repaired under warranty catching it in time before a big re-build was required.

Thank you! I’m really unsure what to do with it, my man maths means the car has to run the rest of the year with no major bills; otherwise I should have leased something

They’re great little cars, but chasing Problems on them really is an expensive minefield isn’t it.

I’m going to give it a full service and replace the extremely leaky rocker cover gasket. Then maybe a de-coke in order.

Sorry for the off topic OP. Any joy yet ?

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