need some help with a mystery misfire

383vett · 04-21-2020, 12:07 PM

Just wondering, did you take the valve cover off?

chknlytle · 04-22-2020, 04:34 PM

Quote:

Originally Posted by 383vett

Just wondering, did you take the valve cover off?

No, I haven't removed the valve cover. Although, I know it's been removed at one point as the valve cover gasket was replaced before I purchased it. At minimum 13k miles ago.

383vett · 04-23-2020, 11:41 AM

Quote:

Originally Posted by chknlytle

No, I haven't removed the valve cover. Although, I know it's been removed at one point as the valve cover gasket was replaced before I purchased it. At minimum 13k miles ago.

I replaced the valve cover gasket a few months ago. There is a one way valve on the inside of the cover that I broke when I was reinstalling it. Upon startup, the car ran funky and threw codes including maf sensor issues. A new cover took care of that. I was thinking possibly you might have the same issue. Good luck.

chknlytle · 04-26-2020, 05:49 PM

Update: driven about 70 miles and 5 hours of run time, and it hasn't had any major misfiring. There was a hiccup twice and I feel when at idle at a stop could be smoother but I don't think a non-enthusiast would notice. I'm glad its drivable now but still scratching my head as to why only now its running fine, after replacing all those spark plugs...

Something new that has come up is I'm getting a code for valvetronic servo motor now. It's intermittent so I'll just leave it be.

TwinSnailz · 04-26-2020, 07:41 PM

Not sure if you have gotten yourself an ISTA software yet but there’s a adaptation reset for the valvetronic. Then you do a -run in - test which I believe it relearn it back.
My wife x3 had the worst rough idle ever that never threw any code. Since i had all the time in the world now, i was messing around and this made the idle smooth as butter.

chknlytle · 05-03-2020, 03:19 AM

Another update, cel is on for misfire cylinder 4. Lol I’m at 101 miles now.

Haven’t been able to look into it yet, but I guess you can see why it’s so frustrating. Cylinder 4 hadn’t given any problems in the past.

chknlytle · 05-09-2020, 08:52 PM

update: I monitored low fuel pressure and the readings are stuck on 101.01 psi under ALL conditions. Even at KOEO. So either a bad low pressure sensor or bad wiring.

Can anyone help with a part number for this sensor? I'm only finding the sensor for the high side.

deeLow · 05-10-2020, 07:02 AM

Quote:

Originally Posted by chknlytle

update: I monitored low fuel pressure and the readings are stuck on 101.01 psi under ALL conditions. Even at KOEO. So either a bad low pressure sensor or bad wiring.

Can anyone help with a part number for this sensor? I'm only finding the sensor for the high side.

How did you monitor the LPFP?

I think I'm chasing something just like you.

chknlytle · 05-10-2020, 04:04 PM

my scan tool has the capability to look at live data at the sensor

Marty in NY · 05-23-2020, 08:13 AM

Quote:

Originally Posted by chknlytle

my scan tool has the capability to look at live data at the sensor

chknlytle did you see this post? .. .. https://x3.xbimmers.com/forums/showthread.php?t=1504218 .. he had similar issues as you and he solved it.

04-21-2020, 12:07 PM	#23
383vett Major 626 Rep 1,044 Posts Drives: 2018 X3 M40i, 2012 X3 Xdrive35 Join Date: Aug 2012 Location: Moraga, California iTrader: (0)	Just wondering, did you take the valve cover off? __________________ 2016 Z06 Vette, 10.53@132 1984 Vette, 406, 10.23@131 2021 SQ5
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04-26-2020, 05:49 PM	#26
chknlytle Private 17 Rep 64 Posts Drives: X3 35i M Sport Join Date: Dec 2017 Location: Oahu iTrader: (0)	Update: driven about 70 miles and 5 hours of run time, and it hasn't had any major misfiring. There was a hiccup twice and I feel when at idle at a stop could be smoother but I don't think a non-enthusiast would notice. I'm glad its drivable now but still scratching my head as to why only now its running fine, after replacing all those spark plugs... Something new that has come up is I'm getting a code for valvetronic servo motor now. It's intermittent so I'll just leave it be.
	Appreciate 0 Quote

04-26-2020, 07:41 PM	#27
TwinSnailz First Lieutenant 75 Rep 357 Posts Drives: 2011 X5//M Join Date: Nov 2009 Location: IL iTrader: (0)	Not sure if you have gotten yourself an ISTA software yet but there’s a adaptation reset for the valvetronic. Then you do a -run in - test which I believe it relearn it back. My wife x3 had the worst rough idle ever that never threw any code. Since i had all the time in the world now, i was messing around and this made the idle smooth as butter.
	Appreciate 0 Quote

05-03-2020, 03:19 AM	#28
chknlytle Private 17 Rep 64 Posts Drives: X3 35i M Sport Join Date: Dec 2017 Location: Oahu iTrader: (0)	Another update, cel is on for misfire cylinder 4. Lol I’m at 101 miles now. Haven’t been able to look into it yet, but I guess you can see why it’s so frustrating. Cylinder 4 hadn’t given any problems in the past.
	Appreciate 0 Quote

05-09-2020, 08:52 PM	#29
chknlytle Private 17 Rep 64 Posts Drives: X3 35i M Sport Join Date: Dec 2017 Location: Oahu iTrader: (0)	update: I monitored low fuel pressure and the readings are stuck on 101.01 psi under ALL conditions. Even at KOEO. So either a bad low pressure sensor or bad wiring. Can anyone help with a part number for this sensor? I'm only finding the sensor for the high side.
	Appreciate 0 Quote

05-10-2020, 04:04 PM	#31
chknlytle Private 17 Rep 64 Posts Drives: X3 35i M Sport Join Date: Dec 2017 Location: Oahu iTrader: (0)	my scan tool has the capability to look at live data at the sensor
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