|
|
08-30-2023, 09:59 PM | #1 |
Enlisted Member
18
Rep 37
Posts |
Octane issues
I have a 2009 30i 6 speed manual no engine mods. I've found that if I use 91 octane my engine will randomly throw a CEL and run rough sometimes it will go away if I turn engine off and back on. When this occurs to combat this I drive at a higher RPM to keep the engine from dying at idle. Reading the engine shows missfire in different cylinders. When I return to 93+ which is found at Shell and other gas stations the engine returns to normal, I clear the faults and it will not have any issues anymore. Does anyone know what would cause this behavior as everywhere I've read I should be able to use 91 to 94 octane gas.
|
08-31-2023, 03:15 AM | #2 |
Captain
220
Rep 810
Posts
Drives: E89 Atacama Yellow 35is
Join Date: May 2022
Location: Scotland..God’s own country
|
Could be many things…
The inlets could be coked up with unburmt oil etc State of the plugs?
__________________
Much modified 2011 Atacama Yellow 35is…previously a much modified 2012 Atacama Yellow 20i MSport
Change history here… https://www.dropbox.com/s/8h1vabklgz...0List.pdf?dl=0 Build thread here… https://z4-forum.com/forum/viewtopic.php?t=131886 |
Appreciate
0
|
08-31-2023, 05:08 PM | #4 |
Private First Class
52
Rep 119
Posts |
How many miles is on your Z4 30i? I believe your engine is the non-turbo n54.
I’d start with the spark plugs, and possibly the coils aren’t up to snuff. It seems odd that 91 octane would cause issues versus 93 octane. I replaced the fuel injectors on my 35i in 2020 because a couple of them were leaking gas into the cylinder. I bought new index 12 injectors and found the existing injectors were index 5’s.
__________________
2009 BMW Z4 35i
2009 Infiniti EX35 Journey AWD 2017 Lincoln MKC AWD |
Appreciate
0
|
08-31-2023, 05:13 PM | #5 | |
Colonel
1000
Rep 2,287
Posts |
Quote:
Start there. |
|
Appreciate
0
|
08-31-2023, 05:23 PM | #6 |
Captain
220
Rep 810
Posts
Drives: E89 Atacama Yellow 35is
Join Date: May 2022
Location: Scotland..God’s own country
|
Apologies if it’s a 30i then it’s a N52 engine which does not suffer from coked inlets..plugs n coils are the main items..
__________________
Much modified 2011 Atacama Yellow 35is…previously a much modified 2012 Atacama Yellow 20i MSport
Change history here… https://www.dropbox.com/s/8h1vabklgz...0List.pdf?dl=0 Build thread here… https://z4-forum.com/forum/viewtopic.php?t=131886 |
Appreciate
0
|
08-31-2023, 06:09 PM | #7 |
Private First Class
52
Rep 119
Posts |
No apologies needed as I’m not well informed on anything other than the n54. And even then there is always something new to learn.
__________________
2009 BMW Z4 35i
2009 Infiniti EX35 Journey AWD 2017 Lincoln MKC AWD |
Appreciate
0
|
09-01-2023, 09:35 PM | #8 |
Enlisted Member
18
Rep 37
Posts |
Thanks for responses! It has 110k on the clock, N52 engine pulled codes and getting various P030X - Cylinder 1 or 3 or 6 Missfire. I've replaced all coil packs a year ago with OEM. I haven't pulled plugs yet. I'm starting to think that after many years my N52 can't handle anything besides 93 octane.
|
Appreciate
0
|
09-03-2023, 05:44 PM | #9 |
New Member
3
Rep 25
Posts |
I've got a new for me s30i (2011) and so have been studying the owner's manual trying to figure the electrics out. I just read today that our engines will work down to 87 octane so I find it surprising that 91 fails in yours.
I'm also surprised that 91 and 93 are available in the same area. My understanding is that in the US, the highest pump octane in general circulation is 93 or 91 in high altitudes where the engine running 93 can comfortably run 91. Have you duplicated this or is it a one time occurance? |
Appreciate
0
|
Post Reply |
Bookmarks |
|
|